practice | Java并发编程与高并发解决方案：http : //coding.imooc.com/class/195.html | Pub Sub library
kandi X-RAY | practice Summary
kandi X-RAY | practice Summary
Java并发编程与高并发解决方案：Java开发企业级权限管理系统：
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Top functions reviewed by kandi - BETA
- The sql session factory bean
- The dynamic datasource
- Main entry point for testing
- Wait for thread to finish
- Process the http request
- Configures the pool configuration
- Return the result as a map
- Run the thread
- Get the target table name
- Bean view servlet
- Entry point
- Main entry point
- Before switching DS
- The example
- Shortcut for testing
- Main program
- Entry point for testing purposes
- Test program
- Computes the total number of tasks
- Main program
- Main method
- Main entry point
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Trending Discussions on practice
QUESTION
Not really sure what caused this but most likely exiting the terminal while my rails server which was connected to PostgreSQL database was closed (not a good practice I know but lesson learned!)
I've already tried the following:
- Rebooting my machine (using MBA M1 2020)
- Restarting PostgreSQL using homebrew
brew services restart postgresql - Re-installing PostgreSQL using Homebrew
- Updating PostgreSQL using Homebrew
- I also tried following this link but when I run
cd Library/Application\ Support/Postgresterminal tells me Postgres folder doesn't exist, so I'm kind of lost already. Although I have a feeling that deleting postmaster.pid would really fix my issue. Any help would be appreciated!
ANSWER
Answered 2022-Jan-13 at 15:19My original answer only included the troubleshooting steps below, and a workaround. I now decided to properly fix it via brute force by removing all clusters and reinstalling, since I didn't have any data there to keep. It was something along these lines, on my Ubuntu 21.04 system:
QUESTION
Wanted to implement type safe matrix multiplication in Haskell. Defined the following:
...ANSWER
Answered 2022-Feb-18 at 09:08This is essentially what singletons are there for. That's a value-level witness for a typeclass that gives you access to this (conceptually reduntant) information that every number can in fact be described in the standard form. A minimal implementation:
QUESTION
I was looking for the canonical implementation of MergeSort on Haskell to port to HOVM, and I found this StackOverflow answer. When porting the algorithm, I realized something looked silly: the algorithm has a "halve" function that does nothing but split a list in two, using half of the length, before recursing and merging. So I thought: why not make a better use of this pass, and use a pivot, to make each half respectively smaller and bigger than that pivot? That would increase the odds that recursive merge calls are applied to already-sorted lists, which might speed up the algorithm!
I've done this change, resulting in the following code:
...ANSWER
Answered 2022-Jan-27 at 19:15Your split splits the list in two ordered halves, so merge consumes its first argument first and then just produces the second half in full. In other words it is equivalent to ++, doing redundant comparisons on the first half which always turn out to be True.
In the true mergesort the merge actually does twice the work on random data because the two parts are not ordered.
The split though spends some work on the partitioning whereas an online bottom-up mergesort would spend no work there at all. But the built-in sort tries to detect ordered runs in the input, and apparently that extra work is not negligible.
QUESTION
How to memory-map a PCI Base Address Register (BAR) from a PCIDriverKit driver (DEXT) to a userspace application?
Memory-mapping from a driver extension to an application can be accomplished by implementing the IOUserClient::CopyClientMemoryForType in the user client subclass (on the driver side) and then calling IOConnectMapMemory64 (from the user-space application side). This has been very nicely and thoroughly explained in this related answer.
The only missing bit is getting an IOMemoryDescriptor corresponding to the desired PCI BAR in order to return it from the CopyClientMemoryForType implementation.
Asked another way, given the following simplified code, what would be the implementation of imaginaryFunctionWhichReturnsTheBARBuffer?
ANSWER
Answered 2022-Jan-16 at 17:01Turns out IOPCIDevice::_CopyDeviceMemoryWithIndex was indeed the function needed to implement this (but the fact that it's private is still an inconvenient).
Bellow is some sample code showing how this could be implemented (the code uses MyDriver for the driver class name and MyDriverUserClient for the user client).
Relevant sections from MyDriver.cpp implementation:
QUESTION
I'd like to abstract some of my GitHub Actions with a reusable workflow.
In order to do this, I need to call my newly defined callable workflow in the format {owner}/{repo}/{path}/{filename}@{ref}
e.g. (from the docs)
...ANSWER
Answered 2021-Oct-20 at 23:55It's as you said: It can't be done at the moment as Github Actions doesn't support expressions with uses attributes.
There is no workaround (yet?) because the workflow interpreter (that also checks the workflow syntax when you push the workflow to the repository) can't get the value from the expression at that moment.
It could maybe work if the workflow was recognized by the interpreter, but it doesn't event appear on the Actions tab as it's considered invalid.
For the moment, you can only use tag, branch ref or commit hash after the @ symbol, the same way you use any action.
QUESTION
Consider the following:
...ANSWER
Answered 2021-Dec-30 at 08:54If you look closely at the specification of ranges::size in [range.prim.size], except when the type of R is the primitive array type, ranges::size obtains the size of r by calling the size() member function or passing it into a free function.
And since the parameter type of transform() function is reference, ranges::size(r) cannot be used as a constant expression in the function body, this means we can only get the size of r through the type of R, not the object of R.
However, there are not many standard range types that contain size information, such as primitive arrays, std::array, std::span, and some simple range adaptors. So we can define a function to detect whether R is of these types, and extract the size from its type in a corresponding way.
QUESTION
For an IOS application, I have a stack that gets called in my tab navigator. I am trying to navigate from a bottom tab screen to a screen in the stack but I am getting the following error.
undefined is not an object (evaluating '_this.props.navigation.navigate')
I would like to render the bottom tab across all screens. I am noticing this causes some interesting issues with goBack() as well in other places.
How can I navigate from the bottom tab screen to a stack screen?
Is the current implementation a bad practice?
I have provided this demo as well as the following code below. I think it is related to prop passing.
...ANSWER
Answered 2021-Dec-21 at 06:07I think that you need to wrap your component withNavigation HOC https://reactnavigation.org/docs/4.x/with-navigation/
That's because your component not directly from the component Navigator, so they don't have this.props.navigation, to make your component have navigation props in Class Component, you need to wrap your component using withNavigation HOC
example:
QUESTION
I'm studying for the final exam for my introduction to C++ class. Our professor gave us this problem for practice:
...Explain why the code produces the following output:
120 200 16 0
ANSWER
Answered 2021-Dec-13 at 20:55It does not default to zero. The sample answer is wrong. Undefined behaviour is undefined; the value may be 0, it may be 100. Accessing it may cause a seg fault, or cause your computer to be formatted.
As to why it's not an error, it's because C++ is not required to do bounds checking on arrays. You could use a vector and use the at function, which throws exceptions if you go outside the bounds, but arrays do not.
QUESTION
I have the following basic architecture:
For reasons I don't want to get into, I want to allow the client to fetch data from either server if they so choose. If they don't care then the load balancer will decide for them.
Is there a best practice for designing the API request?
I've come up with a few options:
- Add an optional query string parameter:
ANSWER
Answered 2021-Dec-15 at 16:48Just create the public domain name for the servers that you allow client to call it directly and then configure the DNS such that it can route the request to them or to the load balancer depending on the domain name of the HTTP request.
For example, you may have the following domain names for the servers:
api.example.comfor the load balancerapi-server1.example.comfor Server1api-server2.example.comfor Server2
Then ask the clients to choose which servers to use by configuring the corresponding domain name in the API call.
One of the real-life example is Mixpanel API. You can see that they have two kind of the servers to let the API client to choose which to use through different domain names.
QUESTION
I work for an org that has a number of internal packages that were created many years ago. These are in the form of package zip archives that were compiled on Windows on R 3.x. Therefore, they can't be installed on R 4.x, and can't be used on Macs or Linux either without being recompiled. So everyone in the entire org is stuck on R 3.6 until this is resolved. I don't have access to the original package source files. They are lost to time....
I want to take these packages, extract the code and data, and update them for modern best practices (roxygen, GitHub repos, testthat etc.). What is the best way of doing this? I have a fair amount of experience with package development. I have already tackled one. I started a new RStudio package project, and going function by function, copying the function code to a new script file, getting and reformatting the help from the help browser as roxygen docs. I've done the same for any internal hidden functions that i could find (via pkg_name::: mostly) , and also the internal datasets. That is all fairly straightforward, but very time consuming. It builds ok, but I haven't yet tested the actual functionality of the code.
I'm currently stuck because there are a couple of standardGeneric method functions for custom S4 class objects. I am completely unfamiliar with these and haven't been able to figure out how to copy them over. Viewing the source code they are wrapped in new() with "standardGeneric" as the first argument (plus a lot more obviously), as opposed to just being a simple function definition for all the other functions. Any help with how to recreate or copy these over would be very welcome.
But maybe I am going about this the wrong way in the first place. I haven't been able to find any helpful suggestions about how to "back engineer" R package source files from a compiled version.
Anyone any ideas?
...ANSWER
Answered 2021-Nov-15 at 15:23Check out if this works in R 3.6.
Below script can automate least part of your problem by writing all function sources into separate and appropriately named .R files. This code will also take care of hidden functions.
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You can use practice 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 practice 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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