Alexei | DEPRECATED - An Image Processing Interface for Android | Computer Vision library

 by   thiagokimo Java Version: 1.4 License: Apache-2.0

kandi X-RAY | Alexei Summary

Alexei is a Java library typically used in Artificial Intelligence, Computer Vision applications. Alexei has no bugs, it has no vulnerabilities, it has build file available, it has a Permissive License and it has low support. You can download it from GitHub, Maven.
A type-safe interface of image processing algorithms.
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                      kandi-support Support

                        summary
                        Alexei has a low active ecosystem.
                        summary
                        It has 182 star(s) with 35 fork(s). There are 9 watchers for this library.
                        summary
                        It had no major release in the last 12 months.
                        summary
                        There are 1 open issues and 2 have been closed. On average issues are closed in 110 days. There are no pull requests.
                        summary
                        It has a neutral sentiment in the developer community.
                        summary
                        The latest version of Alexei is 1.4
                        Alexei Support
                          Best in #Computer Vision
                            Average in #Computer Vision
                            Alexei Support
                              Best in #Computer Vision
                                Average in #Computer Vision

                                  kandi-Quality Quality

                                    summary
                                    Alexei has 0 bugs and 0 code smells.
                                    Alexei Quality
                                      Best in #Computer Vision
                                        Average in #Computer Vision
                                        Alexei Quality
                                          Best in #Computer Vision
                                            Average in #Computer Vision

                                              kandi-Security Security

                                                summary
                                                Alexei has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
                                                summary
                                                Alexei code analysis shows 0 unresolved vulnerabilities.
                                                summary
                                                There are 0 security hotspots that need review.
                                                Alexei Security
                                                  Best in #Computer Vision
                                                    Average in #Computer Vision
                                                    Alexei Security
                                                      Best in #Computer Vision
                                                        Average in #Computer Vision

                                                          kandi-License License

                                                            summary
                                                            Alexei is licensed under the Apache-2.0 License. This license is Permissive.
                                                            summary
                                                            Permissive licenses have the least restrictions, and you can use them in most projects.
                                                            Alexei License
                                                              Best in #Computer Vision
                                                                Average in #Computer Vision
                                                                Alexei License
                                                                  Best in #Computer Vision
                                                                    Average in #Computer Vision

                                                                      kandi-Reuse Reuse

                                                                        summary
                                                                        Alexei releases are available to install and integrate.
                                                                        summary
                                                                        Deployable package is available in Maven.
                                                                        summary
                                                                        Build file is available. You can build the component from source.
                                                                        summary
                                                                        Installation instructions, examples and code snippets are available.
                                                                        Alexei Reuse
                                                                          Best in #Computer Vision
                                                                            Average in #Computer Vision
                                                                            Alexei Reuse
                                                                              Best in #Computer Vision
                                                                                Average in #Computer Vision
                                                                                  Top functions reviewed by kandi - BETA
                                                                                  kandi has reviewed Alexei and discovered the below as its top functions. This is intended to give you an instant insight into Alexei implemented functionality, and help decide if they suit your requirements.
                                                                                  • Calculate the most common color of an image
                                                                                    • Get the most common color from the histogram
                                                                                    • Determine if the RGB array is gray
                                                                                    • Get RGB array from a pixel value
                                                                                  • Calculate the sum of colors for the given bitmap
                                                                                    • Get the pixel matrix from a bitmap
                                                                                    • Reduce an image to a certain number of colors
                                                                                  • Create the drawer view
                                                                                    • Select an drawer item
                                                                                  • Calculate the calculation
                                                                                  • Calculates the bitmap
                                                                                  • This method performs the calculation
                                                                                  • Get actual path from Uri
                                                                                  • Initializes the drawer instance
                                                                                  • Show the calculation
                                                                                  • Gets the defaultCalculator to use
                                                                                  Get all kandi verified functions for this library.
                                                                                  Get all kandi verified functions for this library.

                                                                                  Alexei Key Features

                                                                                  DEPRECATED - An Image Processing Interface for Android

                                                                                  Alexei Examples and Code Snippets

                                                                                  No Code Snippets are available at this moment for Alexei.
                                                                                  Community Discussions

                                                                                  Trending Discussions on Alexei

                                                                                  Cmake does not see OpenCL
                                                                                  chevron right
                                                                                  Javascript arrays email substring into full name, firstname and lastname
                                                                                  chevron right
                                                                                  what happens if we pass threads in executorService execute call in Java multithreading
                                                                                  chevron right
                                                                                  process name (comm) as key for BPF map
                                                                                  chevron right
                                                                                  version name set to Text widget -> Failed assertion: pos 10: 'data != null'
                                                                                  chevron right
                                                                                  Iterating over dataset using GSON parser
                                                                                  chevron right
                                                                                  Simple reverse navigation in datomic
                                                                                  chevron right

                                                                                  QUESTION

                                                                                  Cmake does not see OpenCL
                                                                                  Asked 2022-Mar-17 at 15:32

                                                                                  I am trying to install OpenCL for BEAGLE. First, I have downloaded intel_sdk_for_opencl_applications_2020.3.494.tar.gz from here. Then I unzipped it & run install.sh. Installation was successful. I have BEAGLE installed so I have decided to go to build folder in beagle-lib & run cmake -DCMAKE_INSTALL_PREFIX:PATH=$HOME .. in order to go on to run make install but I get the next message:

                                                                                  -- JAVA_HOME=
                                                                                  -- JNI_INCLUDE_DIRS=/usr/lib/jvm/java/include;/usr/lib/jvm/java/include/linux;/usr/lib/jvm/java/include
                                                                                  -- JNI_LIBRARIES=/usr/lib/jvm/java/lib/libjawt.so;/usr/lib/jvm/java/lib/server/libjvm.so
                                                                                  -- Not using libtools for plugins
                                                                                  -- Could NOT find OpenCL (missing: OpenCL_LIBRARY OpenCL_INCLUDE_DIR)
                                                                                  CUDA_TOOLKIT_ROOT_DIR not found or specified
                                                                                  -- Could NOT find CUDA (missing: CUDA_TOOLKIT_ROOT_DIR CUDA_NVCC_EXECUTABLE CUDA_INCLUDE_DIRS CUDA_CUDART_LIBRARY)
                                                                                  -- Configuring done
                                                                                  -- Generating done
                                                                                  -- Build files have been written to: /export/home/rinkman/beagle-lib/build
                                                                                  

                                                                                  I have tried to set variables both environmental & shell to

                                                                                  OpenCL_LIBRARY=~/intel/system_studio_2020/opencl/SDK/include/CL/cl.h

                                                                                  OpenCL_INCLUDE_DIR=True

                                                                                  But the result of running cmake is the same. I have verified that variables were set up right. So I cannot understand what is wrong. I want to use OpenCL framework in BEAGLE when I am running BEAST 2 software. Please, could anyone help with this?

                                                                                  P.S. I am a noviciate in Linux.

                                                                                  My result of running beast -beagle-info:

                                                                                                          BEAST v2.6.6, 2002-2021
                                                                                               Bayesian Evolutionary Analysis Sampling Trees
                                                                                                         Designed and developed by
                                                                                   Remco Bouckaert, Alexei J. Drummond, Andrew Rambaut & Marc A. Suchard
                                                                                  
                                                                                                     Centre for Computational Evolution
                                                                                                           University of Auckland
                                                                                                         r.bouckaert@auckland.ac.nz
                                                                                                          alexei@cs.auckland.ac.nz
                                                                                  
                                                                                                     Institute of Evolutionary Biology
                                                                                                          University of Edinburgh
                                                                                                             a.rambaut@ed.ac.uk
                                                                                  
                                                                                                      David Geffen School of Medicine
                                                                                                   University of California, Los Angeles
                                                                                                             msuchard@ucla.edu
                                                                                  
                                                                                                        Downloads, Help & Resources:
                                                                                                             http://beast2.org/
                                                                                  
                                                                                    Source code distributed under the GNU Lesser General Public License:
                                                                                                     http://github.com/CompEvol/beast2
                                                                                  
                                                                                                             BEAST developers:
                                                                                     Alex Alekseyenko, Trevor Bedford, Erik Bloomquist, Joseph Heled,
                                                                                   Sebastian Hoehna, Denise Kuehnert, Philippe Lemey, Wai Lok Sibon Li,
                                                                                  Gerton Lunter, Sidney Markowitz, Vladimir Minin, Michael Defoin Platel,
                                                                                            Oliver Pybus, Tim Vaughan, Chieh-Hsi Wu, Walter Xie
                                                                                  
                                                                                                                 Thanks to:
                                                                                            Roald Forsberg, Beth Shapiro and Korbinian Strimmer
                                                                                  
                                                                                  
                                                                                  --- BEAGLE RESOURCES ---
                                                                                  
                                                                                  0 : CPU
                                                                                      Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALERS_RAW SCALERS_LOG VECTOR_SSE VECTOR_NONE THREADING_NONE PROCESSOR_CPU FRAMEWORK_CPU
                                                                                  

                                                                                  One on my computer with Windows for comparison:

                                                                                                          BEAST v2.6.6, 2002-2021
                                                                                               Bayesian Evolutionary Analysis Sampling Trees
                                                                                                         Designed and developed by
                                                                                   Remco Bouckaert, Alexei J. Drummond, Andrew Rambaut & Marc A. Suchard
                                                                                  
                                                                                                     Centre for Computational Evolution
                                                                                                           University of Auckland
                                                                                                         r.bouckaert@auckland.ac.nz
                                                                                                          alexei@cs.auckland.ac.nz
                                                                                  
                                                                                                     Institute of Evolutionary Biology
                                                                                                          University of Edinburgh
                                                                                                             a.rambaut@ed.ac.uk
                                                                                  
                                                                                                      David Geffen School of Medicine
                                                                                                   University of California, Los Angeles
                                                                                                             msuchard@ucla.edu
                                                                                  
                                                                                                        Downloads, Help & Resources:
                                                                                                             http://beast2.org/
                                                                                  
                                                                                    Source code distributed under the GNU Lesser General Public License:
                                                                                                     http://github.com/CompEvol/beast2
                                                                                  
                                                                                                             BEAST developers:
                                                                                     Alex Alekseyenko, Trevor Bedford, Erik Bloomquist, Joseph Heled,
                                                                                   Sebastian Hoehna, Denise Kuehnert, Philippe Lemey, Wai Lok Sibon Li,
                                                                                  Gerton Lunter, Sidney Markowitz, Vladimir Minin, Michael Defoin Platel,
                                                                                            Oliver Pybus, Tim Vaughan, Chieh-Hsi Wu, Walter Xie
                                                                                  
                                                                                                                 Thanks to:
                                                                                            Roald Forsberg, Beth Shapiro and Korbinian Strimmer
                                                                                  
                                                                                  
                                                                                  --- BEAGLE RESOURCES ---
                                                                                  
                                                                                  0 : CPU
                                                                                      Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALERS_RAW SCALERS_LOG VECTOR_SSE VECTOR_NONE THREADING_NONE PROCESSOR_CPU FRAMEWORK_CPU
                                                                                  
                                                                                  1 : NVIDIA GeForce 940MX
                                                                                      Global memory (MB): 2048
                                                                                      Clock speed (Ghz): 1.19
                                                                                      Number of cores: 384
                                                                                      Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH COMPUTATION_ASYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALERS_RAW SCALERS_LOG VECTOR_NONE THREADING_NONE PROCESSOR_GPU FRAMEWORK_CUDA
                                                                                  
                                                                                  2 : Intel(R) HD Graphics 620 (OpenCL 2.1 )
                                                                                      Global memory (MB): 3219
                                                                                      Clock speed (Ghz): 1.00
                                                                                      Number of compute units: 24
                                                                                      Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH COMPUTATION_ASYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALERS_RAW SCALERS_LOG VECTOR_NONE THREADING_NONE PROCESSOR_GPU FRAMEWORK_OPENCL
                                                                                  
                                                                                  3 : Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz (OpenCL 2.1 (Build 10))
                                                                                      Global memory (MB): 8067
                                                                                      Clock speed (Ghz): 2.50
                                                                                      Number of compute units: 4
                                                                                      Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH COMPUTATION_ASYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALERS_RAW SCALERS_LOG VECTOR_NONE THREADING_NONE PROCESSOR_CPU FRAMEWORK_OPENCL
                                                                                  

                                                                                  ANSWER

                                                                                  Answered 2022-Mar-17 at 14:59
                                                                                  Could NOT find OpenCL (missing: OpenCL_LIBRARY OpenCL_INCLUDE_DIR)
                                                                                  

                                                                                  This means that the CMake variables OpenCL_LIBRARY and OpenCL_INCLUDE_DIR are missing, because OpenCL could not be found.

                                                                                  Setting those two as environment variables changes nothing.

                                                                                  You need to tell CMake where things are, if they are not installed in standard directories (as seems to be the case with your OpenCL installation).

                                                                                  Try adding -DOCL_ROOT=path/to/base/of/your/OpenCL to your call to CMake for a package-specific hint, or -DCMAKE_LIBRARY_PATH=path/to/... to make CMake search in that path (in addition to standard paths) for any package it might be looking for. Make sure you cleaned away all cached files beforehand, so that CMake runs clean and does not use cached values.

                                                                                  Source https://stackoverflow.com/questions/71511678

                                                                                  QUESTION

                                                                                  Javascript arrays email substring into full name, firstname and lastname
                                                                                  Asked 2021-Feb-19 at 13:24
                                                                                        I know my questions are similar to other questions but I could not figure it. 
                                                                                  

                                                                                  I am practicing javascript. I have arrays of emails. from that email I want to get three out puts of strings fullname, firstname and lastname inside one map function. I can able to get output first name by reading one stack-overflow questions. I am able get full name by I get output john.doe, I want johndoe. Could not figure it out last name doe.

                                                                                  My example email address is like this: john.doe@co.uk

                                                                                  My expected output is

                                                                                  firstname: 'john'

                                                                                  fullname: johndoe

                                                                                  lastname: doe

                                                                                  This is my code

                                                                                  const Names = (emails) => {
                                                                                    emails.map(i => {
                                                                                      console.log("firstname", i.substring(0, i.indexOf(".")));
                                                                                      console.log("fullname", i.substring(0, i.lastIndexOf("@")));
                                                                                      console.log("lastname");
                                                                                    })
                                                                                  };
                                                                                  
                                                                                  Names(emails)
                                                                                  

                                                                                  const emails = [
                                                                                    "peter.pittman@taitos.com",
                                                                                    "ayden.reed@starkindustries.ss",
                                                                                    "kiefer.franks@amazonia.hk",
                                                                                    "oz.mcguire@tortelloni.zw",
                                                                                    "ellisandro.noble@bluthhousing.party",
                                                                                    "alyas.briggs@taitos.ninja",
                                                                                    "windsor.raymond@hungryhungyhippopottumoses.co.uk",
                                                                                    "daniyal.brock@hungryhungyhippopottumoses.ug",
                                                                                    "samatar.benson@duffbeer.org",
                                                                                    "jaime.freeman@gringottsbank.li",
                                                                                    "aaron.pace@starkindustries.org",
                                                                                    "guerin.mcgowan@taitos.li",
                                                                                    "believe.cote@virtucon.hk",
                                                                                    "abdalroof.ray@oscorp.co.uk",
                                                                                    "blake.barrett@tortelloni.org",
                                                                                    "bradlie.brooks@dundermifflin.ug",
                                                                                    "rayyan.garza@tortelloni.ug",
                                                                                    "declan.wood@dundermifflin.ug",
                                                                                    "tymon.blackburn@oscorp.com",
                                                                                    "joash.duffy@wonkaindustries.ug",
                                                                                    "aleksander.ford@umbrellacorporation.fi",
                                                                                    "jaida.colon@macrosloft.se",
                                                                                    "jevan.jensen@lospolloshermanos.zw",
                                                                                    "abubakar.palmer@dundermifflin.org",
                                                                                    "cator.joyce@lospolloshermanos.org",
                                                                                    "valen.henry@gringottsbank.co.uk",
                                                                                    "taylor-jay.blackburn@wonkaindustries.ug",
                                                                                    "leonardo.mcfadden@goldenstatuettes.co.uk",
                                                                                    "noel.schneider@hungryhungyhippopottumoses.co.uk",
                                                                                    "will.osborne@tasavallanpresidentti.com",
                                                                                    "arda.aguilar@oscorp.fi",
                                                                                    "omri.walls@virtucon.ug",
                                                                                    "lliam.briggs@tortelloni.se",
                                                                                    "kris.lester@amazonia.fi",
                                                                                    "skye.soto@wonkaindustries.se",
                                                                                    "dermot.vang@goldenstatuettes.com",
                                                                                    "cruiz.simmons@cookykitchens.co.uk",
                                                                                    "tymoteusz.riley@tortelloni.fi",
                                                                                    "kaidyn.hays@aperaturescience.party",
                                                                                    "apisai.fletcher@oscorp.co.uk",
                                                                                    "kedrick.mcfadden@cookykitchens.com",
                                                                                    "archibald.elliott@gringottsbank.hk",
                                                                                    "kjae.hurley@umbrellacorporation.com",
                                                                                    "tymon.nielsen@hungryhungyhippopottumoses.fi",
                                                                                    "james.dejesus@amazonia.party",
                                                                                    "reno.silva@gringottsbank.ug",
                                                                                    "tayyib.brooks@taitos.ss",
                                                                                    "cormack.alexander@duffbeer.ss",
                                                                                    "obieluem.guerra@umbrellacorporation.party",
                                                                                    "hector.moran@dundermifflin.co.uk",
                                                                                    "logan.parrish@wonkaindustries.com",
                                                                                    "robin.rivers@starkindustries.zw",
                                                                                    "albie.spence@tasavallanpresidentti.hk",
                                                                                    "qasim.schwartz@duffbeer.zw",
                                                                                    "aodhan.cooper@tasavallanpresidentti.org",
                                                                                    "eassan.hobbs@lospolloshermanos.org",
                                                                                    "parkash.juarez@wonkaindustries.party",
                                                                                    "teos.horton@haxhoont.se",
                                                                                    "kuba.larsen@duffbeer.ninja",
                                                                                    "eisa.beard@umbrellacorporation.li",
                                                                                    "hamza.french@starkindustries.org",
                                                                                    "sung.randall@taitos.ss",
                                                                                    "samir.bond@virtucon.org",
                                                                                    "conlyn.mckee@goldenstatuettes.com",
                                                                                    "thiago.hooper@starkindustries.com",
                                                                                    "demetrius.holland@macrosloft.zw",
                                                                                    "uchenna.oneill@hungryhungyhippopottumoses.zw",
                                                                                    "windsor.steele@hungryhungyhippopottumoses.fi",
                                                                                    "keiryn.macias@tasavallanpresidentti.org",
                                                                                    "kehinde.allen@cookykitchens.hk",
                                                                                    "yuri.ramirez@macrosloft.zw",
                                                                                    "ruan.perez@umbrellacorporation.org",
                                                                                    "dyllon.young@dundermifflin.zw",
                                                                                    "lockey.mcmahon@goldenstatuettes.fi",
                                                                                    "lyndsay.haynes@goldenstatuettes.ninja",
                                                                                    "dareh.grimes@macrosloft.co.uk",
                                                                                    "veeran.vinson@cookykitchens.fi",
                                                                                    "jayke.schroeder@lospolloshermanos.org",
                                                                                    "aronas.berry@bluthhousing.li",
                                                                                    "jonothan.donaldson@gringottsbank.zw",
                                                                                    "kenzeigh.weber@umbrellacorporation.se",
                                                                                    "cesare.huber@tasavallanpresidentti.com",
                                                                                    "uzair.harris@virtucon.ninja",
                                                                                    "kelan.yates@taitos.co.uk",
                                                                                    "thomson.gonzales@bluthhousing.co.uk",
                                                                                    "keaton.green@umbrellacorporation.hk",
                                                                                    "jazeb.kinney@duffbeer.co.uk",
                                                                                    "ronald.flores@starkindustries.hk",
                                                                                    "alastair.moses@umbrellacorporation.se",
                                                                                    "ogheneochuko.ratliff@aperaturescience.se",
                                                                                    "kenton.conley@gringottsbank.ninja",
                                                                                    "kashif.trujillo@bluthhousing.hk",
                                                                                    "saghun.ayers@taitos.hk",
                                                                                    "kamil.eaton@lospolloshermanos.org",
                                                                                    "bailee.henson@goldenstatuettes.li",
                                                                                    "alexei.stanton@haxhoont.li",
                                                                                    "basher.clarke@taitos.li",
                                                                                  ]
                                                                                  
                                                                                  
                                                                                  
                                                                                  const Names = (emails) => {
                                                                                    emails.map(i => {
                                                                                      console.log("firstname", i.substring(0, i.indexOf(".")));
                                                                                      console.log("fullname", i.substring(0, i.lastIndexOf("@")));
                                                                                      console.log("lastname");
                                                                                    })
                                                                                  };
                                                                                  
                                                                                  Names(emails)

                                                                                  ANSWER

                                                                                  Answered 2021-Feb-19 at 05:44

                                                                                  For fullname, you cane use replace(".", "") to remove the '.' So for fullname it can be: i.substring(0, i.lastIndexOf("@")).replace(".", "")

                                                                                  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace

                                                                                  Source https://stackoverflow.com/questions/66272298

                                                                                  QUESTION

                                                                                  what happens if we pass threads in executorService execute call in Java multithreading
                                                                                  Asked 2020-Oct-08 at 11:47

                                                                                  See these two examples:

                                                                                  EXAMPLE 1

                                                                                  public static void main(String[] args) throws InterruptedException {
                                                                                  
                                                                                  ExecutorService executorService = Executors.newCachedThreadPool();
                                                                                          
                                                                                          Thread thread1 = new Thread(new Runnable() {
                                                                                              @Override
                                                                                              public void run() {
                                                                                                  //work
                                                                                                  for (int i = 0 ; i < 5 ; i++){
                                                                                                      try {
                                                                                                          Thread.sleep(1000);
                                                                                                      } catch (InterruptedException e) {
                                                                                                          e.printStackTrace();
                                                                                                      }
                                                                                                  }
                                                                                              }
                                                                                          });
                                                                                          executorService.execute(thread1);
                                                                                          executeService.shutdown();
                                                                                  }
                                                                                  

                                                                                  EXAMPLE 2

                                                                                  public static void main(String[] args) throws InterruptedException {
                                                                                  
                                                                                          ExecutorService executorService = Executors.newCachedThreadPool();
                                                                                  
                                                                                          executorService.execute(new Runnable() {
                                                                                              @Override
                                                                                              public void run() {
                                                                                                  //work
                                                                                                  for (int i = 0 ; i < 5 ; i++){
                                                                                                      try {
                                                                                                          Thread.sleep(1000);
                                                                                                      } catch (InterruptedException e) {
                                                                                                          e.printStackTrace();
                                                                                                      }
                                                                                                  }
                                                                                              }
                                                                                          });
                                                                                          executeService.shutdown();
                                                                                      }
                                                                                  

                                                                                  Results are the same in both cases but a friend of mine from StackOverflow alexei-kaigorodov (in this question) said in a comment that

                                                                                  "executorService is an alternative to treads. There is no sense to put threads in executorService. First, create Runnable, and then either put it as a parameter to a thread and start that thread or submit that runnable to an executorService."

                                                                                  I hope I am clear with my question, so please tell me the difference in passing runnable to ExecuteService vs. passing thread to ExecutableService.

                                                                                  ANSWER

                                                                                  Answered 2020-Oct-08 at 11:47

                                                                                  Thread implements Runnable so the excutor service will accept it as a simple Runnable, and thus calls the Thread.run() method.

                                                                                  Which means that the Thread itself will never be started, unless you call its start() method yourself, in which case the result is definetely undefined.

                                                                                  So you could say the snippets behave the same, you're only passing a Runnable to the ExecutorService and that then executes it by calling the Runnable.run() method.

                                                                                  Source https://stackoverflow.com/questions/64261592

                                                                                  QUESTION

                                                                                  process name (comm) as key for BPF map
                                                                                  Asked 2020-Apr-25 at 20:39

                                                                                  I've been trying to design a tool wherein I can do per-process tracing, but this implies that I need a key for each process so that I can store key-value map pairings for each process. I instinctually don't like using structs or strings as keys, and for a while I was considering how to access inode values for their use as keys. However there are numerous examples that use structures or strings as hashmap keys, and Alexei suggested that process names will be commonly used as a key. That said, I am unable to get a basic implementation of such a hashmap to work. Within the BPF program, the tracepoint isn't able to find the associated value with the process_name key. Perhaps I'm comparing memory locations and not the string literals as intended? Is there something going on under the hood with c_types that creates a mismatch between the keys?

                                                                                  from bcc import BPF
                                                                                  from bcc.utils import printb
                                                                                  from bcc.syscall import syscall_name, syscalls
                                                                                  from ctypes import *
                                                                                  
                                                                                  b = BPF(text = """
                                                                                  
                                                                                  struct procName {
                                                                                      char name[16];
                                                                                  };
                                                                                  
                                                                                  BPF_HASH(attempt, struct procName, u32);
                                                                                  
                                                                                  TRACEPOINT_PROBE(raw_syscalls, sys_exit)
                                                                                  {
                                                                                      u32 *val;
                                                                                      struct procName hKey;
                                                                                      bpf_get_current_comm(hKey.name,16);
                                                                                      val = attempt.lookup(&hKey);
                                                                                  
                                                                                      if (val)
                                                                                      {
                                                                                          bpf_trace_printk("Hello world, I have value %d!\\n", *val);
                                                                                      }
                                                                                  
                                                                                      return 0;
                                                                                  }
                                                                                  """)
                                                                                  
                                                                                  class procName(Structure):
                                                                                      _fields_ = [("name", (c_char_p*16))]
                                                                                  
                                                                                  myFirst = procName(('p','y','t','h','o','n','\0'))
                                                                                  trialUpload[myFirst] = c_int(10)
                                                                                  
                                                                                  while 1:
                                                                                      try:
                                                                                          (task, pid, cpu, flags, ts, msg) = b.trace_fields()
                                                                                      except KeyboardInterrupt:
                                                                                          print("Detaching")
                                                                                          exit()
                                                                                      print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
                                                                                  

                                                                                  ANSWER

                                                                                  Answered 2020-Apr-25 at 20:39

                                                                                  The error in the original code has nothing to do with BCC & BPF and lies within my implemention of ctypes. For starters --

                                                                                  class procName(Structure):
                                                                                      _fields_ = [("name", (c_char_p*16))]
                                                                                  

                                                                                  creates a structure with the field "name". In the above definition, name will be of type *char[16] when I want a char[16]. Second, while this

                                                                                  myFirst = procName(('p','y','t','h','o','n','\0'))
                                                                                  

                                                                                  might work, its not the best practice initialization. This is the correct approach --

                                                                                  class procName(Structure):
                                                                                      _fields_ = [("name", (c_char*16))]
                                                                                  
                                                                                  s = "python"
                                                                                  
                                                                                  mySecond = procName()
                                                                                  mySecond.name = s
                                                                                  

                                                                                  Thus, the full program incorporating a process_name based key and implementation of such to pass data from python is then..

                                                                                  from bcc import BPF
                                                                                  from bcc.utils import printb
                                                                                  from bcc.syscall import syscall_name, syscalls
                                                                                  import ctypes
                                                                                  from ctypes import *
                                                                                  
                                                                                  b = BPF(text = """
                                                                                  
                                                                                  #include 
                                                                                  
                                                                                  struct procName {
                                                                                      char name[16];
                                                                                  };
                                                                                  
                                                                                  BPF_HASH(attempt, struct procName, u32);
                                                                                  
                                                                                  TRACEPOINT_PROBE(raw_syscalls, sys_exit)
                                                                                  {
                                                                                      u32 *myVal;
                                                                                      struct procName key;
                                                                                      bpf_get_current_comm(&(key.name),16);
                                                                                  
                                                                                      myVal = attempt.lookup(&key);
                                                                                  
                                                                                      if (myVal)
                                                                                      {
                                                                                          bpf_trace_printk("values: %d\\n", *myVal);
                                                                                      }
                                                                                  
                                                                                      return 0;
                                                                                  
                                                                                  }
                                                                                  """)
                                                                                  
                                                                                  class procName(Structure):
                                                                                      _fields_ = [("name", (c_char*16))]
                                                                                  
                                                                                  trialUpload = b["attempt"]
                                                                                  
                                                                                  s = "python"
                                                                                  
                                                                                  mySecond = procName()
                                                                                  mySecond.name = s
                                                                                  trialUpload[mySecond] = c_int(5)
                                                                                  
                                                                                  while 1:
                                                                                      try:
                                                                                          (task, pid, cpu, flags, ts, msg) = b.trace_fields()
                                                                                      except KeyboardInterrupt:
                                                                                          print("Detaching")
                                                                                          exit()
                                                                                      print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))
                                                                                  

                                                                                  Source https://stackoverflow.com/questions/61415843

                                                                                  QUESTION

                                                                                  version name set to Text widget -> Failed assertion: pos 10: 'data != null'
                                                                                  Asked 2020-Mar-23 at 16:35

                                                                                  android studio 3.6

                                                                                  I want to set version name to Text widget.

                                                                                  here my snippet:

                                                                                  import 'package:flutter/cupertino.dart';
                                                                                  import 'package:flutter/material.dart';
                                                                                  import 'package:package_info/package_info.dart';
                                                                                  import 'constants.dart' as Constants;
                                                                                  
                                                                                  class SignInForm extends StatefulWidget {
                                                                                    @override
                                                                                    State createState() {
                                                                                      return new _SignInFormState();
                                                                                    }
                                                                                  }
                                                                                  
                                                                                  class _SignInFormState extends State {
                                                                                    final _formKey = GlobalKey();
                                                                                    String _textVersion;
                                                                                  
                                                                                    @override
                                                                                    Widget build(BuildContext context) {
                                                                                      PackageInfo.fromPlatform().then((PackageInfo packageInfo) {
                                                                                        _textVersion =
                                                                                            "ver" + packageInfo.version + "(" + packageInfo.buildNumber + ")";
                                                                                      });
                                                                                  
                                                                                      return Scaffold(
                                                                                          appBar: new AppBar(
                                                                                              centerTitle: true,
                                                                                              title: new Text('Sign in',
                                                                                                  style: TextStyle(fontWeight: FontWeight.bold))),
                                                                                          body: new Container(
                                                                                              child: new Text(_textVersion)));
                                                                                    }
                                                                                  }
                                                                                  

                                                                                  in logcat I get error:

                                                                                  I/flutter: ════════════════════════════════════════════════════════════════════════════════════════════════════
                                                                                  I/flutter: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
                                                                                  I/flutter: The following assertion was thrown building SignInForm(dirty, state: _SignInFormState#61fee):
                                                                                  I/flutter: A non-null String must be provided to a Text widget.
                                                                                  I/flutter: 'package:flutter/src/widgets/text.dart':
                                                                                  I/flutter: Failed assertion: line 302 pos 10: 'data != null'
                                                                                  I/flutter: The relevant error-causing widget was:
                                                                                  I/flutter:   SignInForm file:///home/alexei/dev/Tango-flutter/ios-flutter/lib/main.dart:19:19
                                                                                  I/flutter: When the exception was thrown, this was the stack:
                                                                                  I/flutter: #2      new Text (package:flutter/src/widgets/text.dart:302:10)
                                                                                  I/flutter: #3      _SignInFormState.build (package:flutter_sample/signinform.dart:33:24)
                                                                                  I/flutter: #4      StatefulElement.build (package:flutter/src/widgets/framework.dart:4619:28)
                                                                                  I/flutter: #5      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4502:15)
                                                                                  I/flutter: #6      StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
                                                                                  I/flutter: #7      Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
                                                                                  I/flutter: #8      ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4481:5)
                                                                                  I/flutter: #9      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4666:11)
                                                                                  I/flutter: #10     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4476:5)
                                                                                  I/flutter: ...     Normal element mounting (115 frames)
                                                                                  I/flutter: #125    Element.inflateWidget (package:flutter/src/widgets/framework.dart:3446:14)
                                                                                  I/flutter: #126    MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5947:32)
                                                                                  I/flutter: ...     Normal element mounting (238 frames)
                                                                                  I/flutter: #364    Element.inflateWidget (package:flutter/src/widgets/framework.dart:3446:14)
                                                                                  I/flutter: #365    Element.updateChild (package:flutter/src/widgets/framework.dart:3214:18)
                                                                                  I/flutter: #366    RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:1142:16)
                                                                                  I/flutter: #367    RenderObjectToWidgetElement.mount (package:flutter/src/widgets/binding.dart:1113:5)
                                                                                  I/flutter: #368    RenderObjectToWidgetAdapter.attachToRenderTree. (package:flutter/src/widgets/binding.dart:1055:17)
                                                                                  I/flutter: #369    BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2607:19)
                                                                                  I/flutter: #370    RenderObjectToWidgetAdapter.attachToRenderTree (package:flutter/src/widgets/binding.dart:1054:13)
                                                                                  I/flutter: #371    WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:935:7)
                                                                                  I/flutter: #372    WidgetsBinding.scheduleAttachRootWidget. (package:flutter/src/widgets/binding.dart:917:7)
                                                                                  I/flutter: (elided 13 frames from class _AssertionError, class _RawReceivePortImpl, class _Timer, dart:async, and dart:async-patch)
                                                                                  I/flutter: ════════════════════════════════════════════════════════════════════════════════════════════════════
                                                                                  

                                                                                  ANSWER

                                                                                  Answered 2020-Mar-23 at 14:42

                                                                                  First of all, you should not do anything costly in your build method. Second, _textVersion is null at first when you try to initialize it into the Text because the below line of code will run sometime after the Text is initialized in build.

                                                                                  _textVersion =
                                                                                            "ver" + packageInfo.version + "(" + packageInfo.buildNumber + ")";
                                                                                  

                                                                                  Move your code to the initiState method.

                                                                                  class SignInForm extends StatefulWidget {
                                                                                    @override
                                                                                    _SignInFormState createState() => _SignInFormState();
                                                                                  }
                                                                                  
                                                                                  class _SignInFormState extends State {
                                                                                    String _textVersion = "";
                                                                                  
                                                                                    @override
                                                                                    void initState() {
                                                                                      PackageInfo.fromPlatform().then((PackageInfo packageInfo) {
                                                                                        setState(() {
                                                                                          _textVersion =
                                                                                              "ver" + packageInfo.version + "(" + packageInfo.buildNumber + ")";
                                                                                        });
                                                                                      });
                                                                                      super.initState();
                                                                                    }
                                                                                  
                                                                                    @override
                                                                                    Widget build(BuildContext context) {
                                                                                      return Scaffold(
                                                                                          appBar: new AppBar(
                                                                                              centerTitle: true,
                                                                                              title: new Text('Sign in',
                                                                                                  style: TextStyle(fontWeight: FontWeight.bold))),
                                                                                          body: new Container(child: new Text(_textVersion)));
                                                                                    }
                                                                                  }
                                                                                  

                                                                                  Or you can also create and call another async function from initState, since initState cannot be marked async.

                                                                                   @override
                                                                                    void initState() {
                                                                                      getVersion();
                                                                                      super.initState();
                                                                                    }
                                                                                  
                                                                                    void getVersion() async{
                                                                                      final packageInfo= await PackageInfo.fromPlatform();
                                                                                        setState(() {
                                                                                          _textVersion =
                                                                                              "ver" + packageInfo.version + "(" + packageInfo.buildNumber + ")";
                                                                                        });
                                                                                    }
                                                                                  

                                                                                  Source https://stackoverflow.com/questions/60815048

                                                                                  QUESTION

                                                                                  Iterating over dataset using GSON parser
                                                                                  Asked 2020-Mar-23 at 10:38

                                                                                  I am writing a GSON (Java) parser for the CORD19 dataset https://pages.semanticscholar.org/coronavirus-research of about 40K scientific papers which have been made open for everyone. I want to iterate over the JSON tree using GSON and convert them to HTML. In particular I want to iterate over the entries of the JsonObject elements.

                                                                                  Q1: If anyone has already written an F/OSS CORD19 parser in GSON or other Java parser I'd be delighted.

                                                                                  My specific problem is to iterate over the fields (entries) of a JsonObject.

                                                                                  Data (heavily snipped, but hopefully parsable if snips removed):

                                                                                  {
                                                                                      "paper_id": "b801b7f92cff2155d98f0e3404229c67b60e2f9f",
                                                                                      "metadata": {
                                                                                          "title": "Realtime 2-5A kinetics suggests interferons \u03b2 and \uf06c evade global arrest of translation by RNase L",
                                                                                          "authors": [
                                                                                              {
                                                                                                  "first": "Alisha",
                                                                                                  "middle": [],
                                                                                                  "last": "Chitrakar",
                                                                                                  "suffix": "",
                                                                                                  "affiliation": {},
                                                                                                  "email": ""
                                                                                              },
                                                                                              ... SNIPPED
                                                                                              {
                                                                                                  "first": "Alexei",
                                                                                                  "middle": [],
                                                                                                  "last": "Korennykh",
                                                                                                  "suffix": "",
                                                                                                  "affiliation": {},
                                                                                                  "email": "akorenny@princeton.edu"
                                                                                              }
                                                                                          ]
                                                                                      },
                                                                                      "abstract": [
                                                                                          {
                                                                                              "text": "Cells of all mammals recognize double-stranded RNA (dsRNA) as a foreign material. ...",
                                                                                              "cite_spans": [],
                                                                                              "ref_spans": [],
                                                                                              "section": "Abstract"
                                                                                          },
                                                                                  ... SNIPPED
                                                                                          {
                                                                                              "text": "The 2-5A system is also a surveillance pathway for ...",
                                                                                              "cite_spans": [],
                                                                                              "ref_spans": [],
                                                                                              "section": "Abstract"
                                                                                          }
                                                                                      ],
                                                                                      "body_text": [
                                                                                          {
                                                                                              "text": "Interferons IFNs of type I (\uf061 and \u03b2) and type III ...",
                                                                                              "cite_spans": [],
                                                                                              "ref_spans": [],
                                                                                              "section": "Introduction"
                                                                                          },
                                                                                          {
                                                                                              "text": "To evaluate how the nuclear envelope ...",
                                                                                              "cite_spans": [
                                                                                                  {
                                                                                                      "start": 382,
                                                                                                      "end": 384,
                                                                                                      "text": "50",
                                                                                                      "ref_id": null
                                                                                                  }
                                                                                              ],
                                                                                              "ref_spans": [],
                                                                                              "section": "Diffusion calculations"
                                                                                          }
                                                                                      ],
                                                                                      "bib_entries": {
                                                                                          "BIBREF0": {
                                                                                              "ref_id": "b0",
                                                                                              "title": "Higher-order substrate recognition of eIF2alpha by the RNA-dependent protein kinase PKR",
                                                                                              "authors": [
                                                                                                  {
                                                                                                      "first": "A",
                                                                                                      "middle": [
                                                                                                          "C"
                                                                                                      ],
                                                                                                      "last": "Dar",
                                                                                                      "suffix": ""
                                                                                                  },
                                                                                  ... SNIPPED
                                                                                                  {
                                                                                                      "first": "F",
                                                                                                      "middle": [],
                                                                                                      "last": "Sicheri",
                                                                                                      "suffix": ""
                                                                                                  }
                                                                                              ],
                                                                                              "year": 2005,
                                                                                              "venue": "Cell",
                                                                                              "volume": "122",
                                                                                              "issn": "",
                                                                                              "pages": "887--900",
                                                                                              "other_ids": {}
                                                                                          },
                                                                                          "BIBREF1": {
                                                                                              "ref_id": "b1",
                                                                                              "title": "Increased nuclease activity in cells treated with pppA2'p5'A2'p5' A",
                                                                                              "authors": [
                                                                                                  {
                                                                                                      "first": "A",
                                                                                                      "middle": [
                                                                                                          "G"
                                                                                                      ],
                                                                                                      "last": "Hovanessian",
                                                                                                      "suffix": ""
                                                                                                  },
                                                                                                  ... SNIPPED
                                                                                                  {
                                                                                                      "first": "L",
                                                                                                      "middle": [],
                                                                                                      "last": "Montagnier",
                                                                                                      "suffix": ""
                                                                                                  }
                                                                                              ],
                                                                                              "year": 1979,
                                                                                              "venue": "Proc Natl Acad Sci U S A",
                                                                                              "volume": "76",
                                                                                              "issn": "",
                                                                                              "pages": "3261--3266",
                                                                                              "other_ids": {}
                                                                                          },
                                                                                          "BIBREF2": {
                                                                                              "ref_id": "b2",
                                                                                              "title": "Interferon action--sequence specificity of the ppp(A2'p)nA-dependent ribonuclease",
                                                                                              "authors": [
                                                                                                  {
                                                                                                      "first": "D",
                                                                                                      "middle": [
                                                                                                          "H"
                                                                                                      ],
                                                                                                      "last": "Wreschner",
                                                                                                      "suffix": ""
                                                                                                  },
                                                                                                  ... SNIPPED
                                                                                                  {
                                                                                                      "first": "I",
                                                                                                      "middle": [
                                                                                                          "M"
                                                                                                      ],
                                                                                                      "last": "Kerr",
                                                                                                      "suffix": ""
                                                                                                  }
                                                                                              ],
                                                                                              "year": 1981,
                                                                                              "venue": "Nature",
                                                                                              "volume": "289",
                                                                                              "issn": "",
                                                                                              "pages": "414--421",
                                                                                              "other_ids": {}
                                                                                          },
                                                                                          ... SNIPPED
                                                                                          "BIBREF47": {
                                                                                              "ref_id": "b47",
                                                                                              "title": "Size-dependent DNA mobility in cytoplasm and nucleus",
                                                                                              "authors": [
                                                                                                  {
                                                                                                      "first": "G",
                                                                                                      "middle": [
                                                                                                          "L"
                                                                                                      ],
                                                                                                      "last": "Lukacs",
                                                                                                      "suffix": ""
                                                                                                  }
                                                                                              ],
                                                                                              "year": 2000,
                                                                                              "venue": "J Biol Chem",
                                                                                              "volume": "275",
                                                                                              "issn": "",
                                                                                              "pages": "1625--1634",
                                                                                              "other_ids": {}
                                                                                          },
                                                                                          "BIBREF48": {
                                                                                              "ref_id": "b48",
                                                                                              "title": "Modeling transmembrane transport through cell membrane wounds created by acoustic cavitation",
                                                                                              "authors": [
                                                                                                  {
                                                                                                      "first": "V",
                                                                                                      "middle": [],
                                                                                                      "last": "Zarnitsyn",
                                                                                                      "suffix": ""
                                                                                                  },
                                                                                                  ... SNIPPED
                                                                                                  {
                                                                                                      "first": "M",
                                                                                                      "middle": [
                                                                                                          "R"
                                                                                                      ],
                                                                                                      "last": "Prausnitz",
                                                                                                      "suffix": ""
                                                                                                  }
                                                                                              ],
                                                                                              "year": 2008,
                                                                                              "venue": "Biophys J",
                                                                                              "volume": "95",
                                                                                              "issn": "",
                                                                                              "pages": "4124--4162",
                                                                                              "other_ids": {}
                                                                                          }
                                                                                      },
                                                                                      ... SNIPPED
                                                                                      "back_matter": [
                                                                                          {
                                                                                              "text": "We are grateful to Prof. Bonnie Bassler (Princeton University) for All NS All NS NS ** All ****",
                                                                                              "cite_spans": [],
                                                                                              "ref_spans": [],
                                                                                              "section": "Acknowledgments:"
                                                                                          }
                                                                                      ]
                                                                                  }
                                                                                  

                                                                                  There is a schema on the CORD-19 site, but entries such as BIBREF1 ... BIBREF48 vary in number over each data set. (Q what is the precise name for a BIBREF object - entry? Child?)

                                                                                  My current code is:

                                                                                      @Test
                                                                                      public void testReadJSON() {
                                                                                  
                                                                                          File jsonFile = new File(BIORXIV_MEDRXIV, "b801b7f92cff2155d98f0e3404229c67b60e2f9f.json");
                                                                                          JsonObject oo = null;
                                                                                          try {
                                                                                              String resultsJsonString = IOUtils.toString(new FileInputStream(jsonFile), "UTF-8");
                                                                                              JsonParser parser = new JsonParser();
                                                                                              oo = (JsonObject) parser.parse(resultsJsonString);
                                                                                  
                                                                                          } catch (Exception e) {
                                                                                              throw new RuntimeException("Cannot read CORD19 file: "+jsonFile, e);
                                                                                          }
                                                                                  
                                                                                          String paperId = oo.get("paper_id").getAsString();
                                                                                          System.out.println("id: "+paperId);
                                                                                  
                                                                                          JsonElement metadata = oo.get("metadata");
                                                                                          JsonObject metadataObject = metadata.getAsJsonObject();
                                                                                          String title = metadataObject.get("title").getAsString();
                                                                                          System.out.println("title: "+title);
                                                                                  
                                                                                          JsonElement authorsObject = metadataObject.get("authors");
                                                                                          System.out.println("Auth: "+authorsObject);
                                                                                          JsonArray authors = authorsObject.getAsJsonArray();
                                                                                          for (int i = 0; i < authors.size(); i++) {
                                                                                              System.out.println(authors.get(i));
                                                                                          }
                                                                                  
                                                                                          JsonElement abstrakt = oo.get("abstract");
                                                                                          System.out.println("abstract: "+abstrakt);
                                                                                          JsonArray texts = abstrakt.getAsJsonArray();
                                                                                          for (int i = 0; i < texts.size(); i++) {
                                                                                              System.out.println(texts.get(i));
                                                                                          }
                                                                                  
                                                                                          JsonElement bodyText = oo.get("body_text");
                                                                                          System.out.println("bodyText: "+bodyText);
                                                                                          texts = bodyText.getAsJsonArray();
                                                                                          for (int i = 0; i < texts.size(); i++) {
                                                                                              System.out.println(texts.get(i));
                                                                                          }
                                                                                  
                                                                                          JsonElement bibEntries = oo.get("bib_entries");
                                                                                          System.out.println("bibEntries: "+bibEntries.getClass()+bibEntries);
                                                                                          JsonObject obj = bibEntries.getAsJsonObject();
                                                                                          // WHAT TO WRITE HERE?
                                                                                  
                                                                                      }
                                                                                  
                                                                                  }
                                                                                  

                                                                                  (Additional Q. I am learning Java8 so would appreciate answers in Java8 streams as well as Java7)

                                                                                  (Additional Q. [I would not normally "advertise" on Stack Overflow, but these are not normal times, and think this will help save lives, and provide opportunities for Stack Overflow members to contribute skills] I have set up volunteer projects to hack this dataset. I have had many years of extracting knowledge from scientific papers and believe that the existing papers may contain valuable pointers to new scientific knowledge.

                                                                                  Also - does Stack Overflow have a way of collecting expertise that can be re-used specifically for COVID-19?

                                                                                  ANSWER

                                                                                  Answered 2020-Mar-23 at 09:59

                                                                                  GSON's JsonObject offers the entrySet() method for iterating the contents.

                                                                                  for(Map.Entry entry : obj.entrySet()) {
                                                                                      String key = entry.getKey();     // BIBREF0
                                                                                      JsonElement value = entry.getValue();   // details, can be cast to JsonObject
                                                                                      processBibRef((JsonObject)value);       // For example
                                                                                  }
                                                                                  

                                                                                  Streams won't help much here, but separate methods for subelements should be used to structure the code better, as in the example.

                                                                                  As can be seen, manually parsing JSON is cumbersome with Java, and when you're transforming JSON to for example HTML, the extra step of converting to objects makes other less typesafe languages such as Javascript more attractive.

                                                                                  Source https://stackoverflow.com/questions/60810617

                                                                                  QUESTION

                                                                                  Simple reverse navigation in datomic
                                                                                  Asked 2020-Jan-11 at 22:48

                                                                                  Learning Datomic, and having trouble with a basic case. Given a simple schema containing:

                                                                                  :club/name
                                                                                  :club/members (ref, cardinality many)
                                                                                  

                                                                                  and

                                                                                  :people/name
                                                                                  

                                                                                  So it might be populated (basically) like this:

                                                                                  [
                                                                                  {:club/name "Carpentry" :club/members [:person/name "liliana" :person/name "alexei"}]}
                                                                                  {:club/name "Taxidermy" :club/members [:person/name "karenna" :person/name "alexei"}]}
                                                                                  etc.
                                                                                  ]
                                                                                  

                                                                                  I want to do a reverse navigation to find "all the clubs 'alexei' is in". If I do this, I get only one club:

                                                                                  d/q '[:find (pull ?g [ {:club/_members [:club/name]}]) 
                                                                                         :in $ 
                                                                                         :where 
                                                                                         [?g :person/name "alexei"]
                                                                                         ]
                                                                                       (d/db conn))
                                                                                  

                                                                                  I would expect to get two hits for this example data. Am I modeling it backwards? Do I have to create a separate entity to express person-in-club?

                                                                                  Thanks much!

                                                                                  ANSWER

                                                                                  Answered 2020-Jan-11 at 22:48

                                                                                  I'm learning Datomic too, currently, I'm using Datahike because the syntax is similar & easier to dev on imo

                                                                                  Anyway I tried your example and came up with this:

                                                                                  (ns club
                                                                                    (:require [datahike.api :as d]))
                                                                                  
                                                                                  (def schema
                                                                                    [{:db/ident :person/name
                                                                                      :db/valueType :db.type/string
                                                                                      :db/cardinality :db.cardinality/one}
                                                                                     {:db/ident :club/name
                                                                                      :db/valueType :db.type/string
                                                                                      :db/cardinality :db.cardinality/one}
                                                                                     {:db/ident :club/members
                                                                                      :db/valueType :db.type/ref
                                                                                      :db/cardinality :db.cardinality/many}])
                                                                                  
                                                                                  (def database "datahike:mem://example")
                                                                                  
                                                                                  (def data
                                                                                    [{:club/name "Carpentry" :club/members [{:person/name "liliana"} {:person/name "alexei"}]}
                                                                                     {:club/name "Taxidermy" :club/members [{:person/name "karenna"} {:person/name "alexei"}]}])
                                                                                  
                                                                                  (comment
                                                                                    (d/create-database database)
                                                                                  
                                                                                    (def conn (d/connect database))
                                                                                  
                                                                                    (d/transact conn schema)
                                                                                  
                                                                                    (d/transact conn data)
                                                                                  
                                                                                    (d/q '[:find (pull ?e [{:club/_members [:club/name]}])
                                                                                           :where [?e :person/name "alexei"]]
                                                                                         @conn))
                                                                                  

                                                                                  Result:

                                                                                  ([#:club{:_members [#:club{:name "Carpentry"}]}] [#:club{:_members [#:club{:name "Taxidermy"}]}])
                                                                                  

                                                                                  Which I think is what you were looking for

                                                                                  There are two things that stand out to me in your comment that might have caused issue:

                                                                                  • Your schema says people/name but your data says person/name
                                                                                  • The club members vector in your data looks like it's mixing [ { I think you need a vector of two maps in there

                                                                                  But those issues might not be in your source code, could debug further if you'd like to share your source code

                                                                                  Hope this helps

                                                                                  Source https://stackoverflow.com/questions/59640205

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                                                                                  Vulnerabilities

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                                                                                  Install Alexei

                                                                                  You can download it from GitHub, Maven.
                                                                                  You can use Alexei like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the Alexei component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .

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