/**
* Copyright 2013-2016 Guoqiang Chen, Shanghai, China. All rights reserved.
*
* Author: Guoqiang Chen
* Email: subchen@gmail.com
* WebURL: https://github.com/subchen
*
* 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 jetbrick.util.concurrent;
import java.util.concurrent.atomic.AtomicReference;
public abstract class AtomicSafeInitializer<T> implements ConcurrentInitializer<T> {
private final AtomicReference<AtomicSafeInitializer<T>> factory = new AtomicReference<AtomicSafeInitializer<T>>();
private final AtomicReference<T> reference = new AtomicReference<T>();
@Override
public final T get() {
T result;
while ((result = reference.get()) == null) {
if (factory.compareAndSet(null, this)) {
reference.set(initialize());
}
}
return result;
}
protected abstract T initialize();
}