001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.util;
019
020import java.util.concurrent.ConcurrentHashMap;
021import java.util.concurrent.locks.ReentrantReadWriteLock;
022import org.apache.yetus.audience.InterfaceAudience;
023
024@InterfaceAudience.Private
025public class IdReadWriteLockStrongRef<T> extends IdReadWriteLock<T> {
026
027  final ConcurrentHashMap<T, ReentrantReadWriteLock> map = new ConcurrentHashMap<>();
028
029  @Override
030  public ReentrantReadWriteLock getLock(T id) {
031    ReentrantReadWriteLock existing = map.get(id);
032    if (existing != null) {
033      return existing;
034    }
035
036    ReentrantReadWriteLock newLock = new ReentrantReadWriteLock();
037    existing = map.putIfAbsent(id, newLock);
038    if (existing == null) {
039      return newLock;
040    } else {
041      return existing;
042    }
043  }
044
045}