JetBrains Xodus is a Java transactional schema-less embedded database used by JetBrains YouTrack and JetBrains Hub.
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README.md

official JetBrains project TeamCity (build status) Maven Central License Pure Java + Kotlin Stack Overflow

JetBrains Xodus is a transactional schema-less embedded database that is written in Java and Kotlin. It was initially developed for JetBrains YouTrack, an issue tracking and project management tool. Xodus is also used in JetBrains Hub, the user management platform for JetBrains' team tools, and in some internal JetBrains projects.

  • Xodus is transactional and fully ACID-compliant.
  • Xodus is highly concurrent. Reads are completely non-blocking due to MVCC and true snapshot isolation.
  • Xodus is schema-less and agile. It does not require schema migrations or refactorings.
  • Xodus is embedded. It does not require installation or administration.
  • Xodus is written in pure Java and Kotlin.
  • Xodus is free and licensed under Apache 2.0.

Hello Worlds!

To start using Xodus, define dependencies:

<!-- in Maven project -->
<dependency>
    <groupId>org.jetbrains.xodus</groupId>
    <artifactId>xodus-openAPI</artifactId>
    <version>1.2.3</version>
</dependency>
// in Gradle project
dependencies {
    compile 'org.jetbrains.xodus:xodus-openAPI:1.2.3'
}

Read more about managing dependencies.

There are three different ways to deal with data, which results in three different API layers: Environments, Entity Stores and Virtual File Systems.

Environments

Add dependency on org.jetbrains.xodus:xodus-environment:1.2.3.

final Environment env = Environments.newInstance("/home/me/.myAppData");
env.executeInTransaction(new TransactionalExecutable() {
    @Override
    public void execute(@NotNull final Transaction txn) {
        final Store store = env.openStore("Messages", StoreConfig.WITHOUT_DUPLICATES, txn);
        store.put(txn, StringBinding.stringToEntry("Hello"), StringBinding.stringToEntry("World!"));
    }
});
env.close();

Entity Stores

Add dependency on org.jetbrains.xodus:xodus-entity-store:1.2.3.

final PersistentEntityStore entityStore = PersistentEntityStores.newInstance("/home/me/.myAppData");
entityStore.executeInTransaction(new StoreTransactionalExecutable() {
    @Override
    public void execute(@NotNull final StoreTransaction txn) {
        final Entity message = txn.newEntity("Message");
        message.setProperty("hello", "World!");
    }
});
entityStore.close();

Virtual File Systems

Add dependency on org.jetbrains.xodus:xodus-vfs:1.2.3.

final Environment env = Environments.newInstance("/home/me/.myAppData");
final VirtualFileSystem vfs = new VirtualFileSystem(env);
env.executeInTransaction(new TransactionalExecutable() {
    @Override
    public void execute(@NotNull final Transaction txn) {
        final File file = vfs.createFile(txn, "Messages");
        try (DataOutputStream output = new DataOutputStream(vfs.writeFile(txn, file))) {
            output.writeUTF("Hello ");
            output.writeUTF("World!");
        }
    }
});
vfs.shutdown();
env.close(); 

Building from Source

Gradle is used to build, test, and publish. JDK 1.8 is required. To build the project, run:

./gradlew build

To assemble JARs and skip running tests, run:

./gradlew assemble

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