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lmdbjava | Lightning Memory Database for Java: a low latency | Key Value Database library

 by   lmdbjava Java Version: Current License: Apache-2.0

 by   lmdbjava Java Version: Current License: Apache-2.0

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kandi X-RAY | lmdbjava Summary

lmdbjava is a Java library typically used in Database, Key Value Database applications. lmdbjava 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.
Lightning Memory Database (LMDB) for Java: a low latency, transactional, sorted, embedded, key-value store
Support
Support
Quality
Quality
Security
Security
License
License
Reuse
Reuse

kandi-support Support

  • lmdbjava has a low active ecosystem.
  • It has 595 star(s) with 91 fork(s). There are 37 watchers for this library.
  • It had no major release in the last 12 months.
  • There are 13 open issues and 136 have been closed. On average issues are closed in 30 days. There are 1 open pull requests and 0 closed requests.
  • It has a neutral sentiment in the developer community.
  • The latest version of lmdbjava is current.
lmdbjava Support
Best in #Key Value Database
Average in #Key Value Database
lmdbjava Support
Best in #Key Value Database
Average in #Key Value Database

quality kandi Quality

  • lmdbjava has 0 bugs and 0 code smells.
lmdbjava Quality
Best in #Key Value Database
Average in #Key Value Database
lmdbjava Quality
Best in #Key Value Database
Average in #Key Value Database

securitySecurity

  • lmdbjava has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
  • lmdbjava code analysis shows 0 unresolved vulnerabilities.
  • There are 0 security hotspots that need review.
lmdbjava Security
Best in #Key Value Database
Average in #Key Value Database
lmdbjava Security
Best in #Key Value Database
Average in #Key Value Database

license License

  • lmdbjava is licensed under the Apache-2.0 License. This license is Permissive.
  • Permissive licenses have the least restrictions, and you can use them in most projects.
lmdbjava License
Best in #Key Value Database
Average in #Key Value Database
lmdbjava License
Best in #Key Value Database
Average in #Key Value Database

buildReuse

  • lmdbjava releases are not available. You will need to build from source code and install.
  • Build file is available. You can build the component from source.
lmdbjava Reuse
Best in #Key Value Database
Average in #Key Value Database
lmdbjava Reuse
Best in #Key Value Database
Average in #Key Value Database
Top functions reviewed by kandi - BETA

kandi has reviewed lmdbjava and discovered the below as its top functions. This is intended to give you an instant insight into lmdbjava implemented functionality, and help decide if they suit your requirements.

  • This method will throw exceptions for error messages .
  • Compare two buffers .
  • Extract native library .
  • Executes the timer for the specified duration .
  • Returns information about this environment .
  • Compare two byte arrays .
  • Put multiple elements into the map .
  • Executes the iterator operation .
  • Searches for the field with the given name .
  • Returns the set of all available flags .

lmdbjava Key Features

Lightning Memory Database (LMDB) for Java: a low latency, transactional, sorted, embedded, key-value store

LMDB Java retrieve all values with same key

copy iconCopydownload iconDownload
  @Test
  public void dupSortKeyRange() {

    final Dbi<ByteBuffer> db = env.openDbi(DB_1, MDB_CREATE, MDB_DUPSORT);

    try (Txn<ByteBuffer> txn = env.txnWrite()) {
      db.put(txn, bb(5), bb(6));
      db.put(txn, bb(5), bb(7));
      db.put(txn, bb(5), bb(8));
      db.put(txn, bb(6), bb(9));
      txn.commit();
    }

    try (Txn<ByteBuffer> txn = env.txnRead()) {
      ByteBuffer key = bb(5);

      List<Integer> keyValues = new ArrayList<>();
      CursorIterator<ByteBuffer> cursor = db.iterate(txn, KeyRange.closed(key, key));
      for (CursorIterator.KeyVal<ByteBuffer> kv : cursor.iterable()) {
        ByteBuffer value = kv.val().get(new byte[kv.val().remaining()]);
        keyValues.add(value.getInt(0));
      }

      assertEquals(3, keyValues.size(), 0);
      assertTrue(keyValues.containsAll(Arrays.asList(6, 7, 8)));
    }
  }

Using lmdbjava in Clojure

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Env<T>  open(File path, int mode, EnvFlags... flags)
(.open (.setMaxDbs (.setMapSize (Env/create) 10485760) 1) path (into-array org.lmdbjava.EnvFlags []))
-----------------------
Env<T>  open(File path, int mode, EnvFlags... flags)
(.open (.setMaxDbs (.setMapSize (Env/create) 10485760) 1) path (into-array org.lmdbjava.EnvFlags []))

Akka 2.5 Distributed Data on Docker + Alpine Linux

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akka.cluster.sharding.distributed-data.durable.keys = []

Community Discussions

Trending Discussions on lmdbjava
  • How do I open a LMDB database in Java?
  • LMDB Java retrieve all values with same key
  • Using lmdbjava in Clojure
  • Akka 2.5 Distributed Data on Docker + Alpine Linux
Trending Discussions on lmdbjava

QUESTION

How do I open a LMDB database in Java?

Asked 2019-Nov-19 at 20:27

I am trying to open a LMDB database using its Java API.

This is my Database class:

import java.io.File;
import java.nio.ByteBuffer;
import java.nio.file.Paths;
import org.lmdbjava.Dbi;
import static org.lmdbjava.DbiFlags.MDB_CREATE;
import org.lmdbjava.Env;
import org.lmdbjava.Txn;

public class Database {

    private String dbName;
    private String dbDirectoryName;
    private File dbDirectory;
    private Env<ByteBuffer> dbEnvironment;
    private Dbi<ByteBuffer> db;

    public Database(String _dbDirectoryName, String _dbName) {

        dbName = _dbName;
        dbDirectoryName = _dbDirectoryName;
        dbDirectory = new File(dbDirectoryName);

        dbEnvironment = Env.create().setMapSize(1_073_741_824).setMaxDbs(1).open(dbDirectory);
        db = dbEnvironment.openDbi(dbName, MDB_CREATE);

    }        

    public void Close() {
        dbEnvironment.close();
    }


}

And my main class:

public class TestApp {

    public static void main(String[] args) {

        Database db = new Database("./data", "DB.TEST");

    }

}

I have double check that directory data exists.

I get the following error:

run:
Exception in thread "main" java.lang.NoClassDefFoundError: jnr/ffi/byref/PointerByReference
    at org.lmdbjava.Env$Builder.open(Env.java:460)
    at org.lmdbjava.Env$Builder.open(Env.java:486)
    at database.Database.<init>(Database.java:41)
    at TestApp.main(TestApp.java:25)
Caused by: java.lang.ClassNotFoundException: jnr.ffi.byref.PointerByReference
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
    ... 4 more

This test tries to follow the existing documentation for LMDB Java API:

https://github.com/lmdbjava/lmdbjava/blob/master/src/test/java/org/lmdbjava/TutorialTest.java

ANSWER

Answered 2019-Nov-19 at 09:26

Most Likely you are missing dependency, or jar file containing jnr.ffi.byref.PointerByReference class is missing from Classpath.

Check: https://javarevisited.blogspot.com/2011/08/classnotfoundexception-in-java-example.html

Depends on whichever tool you are using, add dependency to pom.xml or build.gradle or add it to classpath.

Source https://stackoverflow.com/questions/58927486

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

No vulnerabilities reported

Install lmdbjava

You can download it from GitHub.
You can use lmdbjava 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 lmdbjava 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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