com.hazelcast.util.ConcurrencyUtil Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2015, Hazelcast, Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.util;
import java.util.concurrent.ConcurrentMap;
/**
* Utility methods to getOrPutSynchronized and getOrPutIfAbsent in a thread safe way
* from ConcurrentMap with a ConstructorFunction.
*/
public final class ConcurrencyUtil {
private ConcurrencyUtil() {
}
public static V getOrPutSynchronized(ConcurrentMap map, K key,
final Object mutex, ConstructorFunction func) {
if (mutex == null) {
throw new NullPointerException();
}
V value = map.get(key);
if (value == null) {
synchronized (mutex) {
value = map.get(key);
if (value == null) {
value = func.createNew(key);
map.put(key, value);
}
}
}
return value;
}
public static V getOrPutIfAbsent(ConcurrentMap map, K key, ConstructorFunction func) {
V value = map.get(key);
if (value == null) {
value = func.createNew(key);
V current = map.putIfAbsent(key, value);
value = current == null ? value : current;
}
return value;
}
}