org.rocksdb.AbstractImmutableNativeReference Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of rocksdbjni Show documentation

RocksDB fat jar that contains .so files for linux32 and linux64 (glibc and musl-libc), jnilib files for Mac OSX, and a .dll for Windows x64.

There is a newer version: 8.9.1.2

Show newest version

// Copyright (c) 2016, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root directory).

package org.rocksdb;

import java.util.concurrent.atomic.AtomicBoolean;

/**
 * Offers functionality for implementations of
 * {@link AbstractNativeReference} which have an immutable reference to the
 * underlying native C++ object
 */
//@ThreadSafe
public abstract class AbstractImmutableNativeReference
    extends AbstractNativeReference {

  /**
   * A flag indicating whether the current {@code AbstractNativeReference} is
   * responsible to free the underlying C++ object
   */
  protected final AtomicBoolean owningHandle_;

  protected AbstractImmutableNativeReference(final boolean owningHandle) {
    this.owningHandle_ = new AtomicBoolean(owningHandle);
  }

  @Override
  public boolean isOwningHandle() {
    return owningHandle_.get();
  }

  /**
   * Releases this {@code AbstractNativeReference} from  the responsibility of
   * freeing the underlying native C++ object
   * 
   * This will prevent the object from attempting to delete the underlying
   * native object in {@code close()}. This must be used when another object
   * takes over ownership of the native object or both will attempt to delete
   * the underlying object when closed.
   * 

   * When {@code disOwnNativeHandle()} is called, {@code close()} will
   * subsequently take no action. As a result, incorrect use of this function
   * may cause a memory leak.
   * 
   */
  protected final void disOwnNativeHandle() {
    owningHandle_.set(false);
  }

  @Override
  public void close() {
    if (owningHandle_.compareAndSet(true, false)) {
      disposeInternal();
    }
  }

  /**
   * The helper function of {@link AbstractImmutableNativeReference#close()}
   * which all subclasses of {@code AbstractImmutableNativeReference} must
   * implement to release their underlying native C++ objects.
   */
  protected abstract void disposeInternal();
}