/*
* Copyright (c) 2008-2013, 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;
/**
* @author mdogan 1/28/13
*/
public class
ConcurrencyUtil {
private
ConcurrencyUtil() {
}
public static <K,V> V
getOrPutSynchronized(
ConcurrentMap<K, V>
map, K
key, final
Object mutex,
ConstructorFunction<K,V>
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 <K,V> V
getOrPutIfAbsent(
ConcurrentMap<K, V>
map, K
key,
ConstructorFunction<K,V>
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;
}
}