/*
* Copyright 2016 NAVER Corp.
*
* 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.navercorp.pinpoint.profiler.context.scope;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
/**
* @author Woonduk Kang(emeroad)
*/
public class ConcurrentPool<K, V> implements Pool<K, V> {
private final ConcurrentMap<K, V> pool = new ConcurrentHashMap<K, V>();
private final PoolObjectFactory<K, V> objectFactory;
public ConcurrentPool(PoolObjectFactory<K, V> objectFactory) {
if (objectFactory == null) {
throw new NullPointerException("objectFactory must not be null");
}
this.objectFactory = objectFactory;
}
@Override
public V get(K key) {
if (key == null) {
throw new IllegalArgumentException("key must not be null");
}
final V alreadyExist = this.pool.get(key);
if (alreadyExist != null) {
return alreadyExist;
}
final V newValue = this.objectFactory.create(key);
final V oldValue = this.pool.putIfAbsent(key, newValue);
if (oldValue != null) {
return oldValue;
}
return newValue;
}
}