org.rocksdb.ClockCache 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: 0.1.0-RC.5

Show newest version

// Copyright (c) 2011-present, 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;

/**
 * Similar to {@link LRUCache}, but based on the CLOCK algorithm with
 * better concurrent performance in some cases
 */
public class ClockCache extends Cache {

  /**
   * Create a new cache with a fixed size capacity.
   *
   * @param capacity The fixed size capacity of the cache
   */
  public ClockCache(final long capacity) {
    super(newClockCache(capacity, -1, false));
  }

  /**
   * Create a new cache with a fixed size capacity. The cache is sharded
   * to 2^numShardBits shards, by hash of the key. The total capacity
   * is divided and evenly assigned to each shard.
   * numShardBits = -1 means it is automatically determined: every shard
   * will be at least 512KB and number of shard bits will not exceed 6.
   *
   * @param capacity The fixed size capacity of the cache
   * @param numShardBits The cache is sharded to 2^numShardBits shards,
   *     by hash of the key
   */
  public ClockCache(final long capacity, final int numShardBits) {
    super(newClockCache(capacity, numShardBits, false));
  }

  /**
   * Create a new cache with a fixed size capacity. The cache is sharded
   * to 2^numShardBits shards, by hash of the key. The total capacity
   * is divided and evenly assigned to each shard. If strictCapacityLimit
   * is set, insert to the cache will fail when cache is full.
   * numShardBits = -1 means it is automatically determined: every shard
   * will be at least 512KB and number of shard bits will not exceed 6.
   *
   * @param capacity The fixed size capacity of the cache
   * @param numShardBits The cache is sharded to 2^numShardBits shards,
   *     by hash of the key
   * @param strictCapacityLimit insert to the cache will fail when cache is full
   */
  public ClockCache(final long capacity, final int numShardBits,
      final boolean strictCapacityLimit) {
    super(newClockCache(capacity, numShardBits, strictCapacityLimit));
  }

  private native static long newClockCache(final long capacity,
      final int numShardBits, final boolean strictCapacityLimit);
  @Override protected final native void disposeInternal(final long handle);
}