/*
* This file is part of NucleusFramework for Bukkit, licensed under the MIT License (MIT).
*
* Copyright (c) JCThePants (www.jcwhatever.com)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.jcwhatever.nucleus.utils;
/**
* Retrieve singleton instances per current thread.
*/
public class ThreadSingletons<S> extends ThreadLocal<S> {
private final ISingletonFactory<S> _factory;
/**
* Constructor.
*
* @param factory The singleton instance factory.
*/
public ThreadSingletons(ISingletonFactory<S> factory) {
PreCon.notNull(factory);
_factory = factory;
}
/**
* @throws UnsupportedOperationException
*/
@Override
public void set(S value) {
throw new UnsupportedOperationException("Cannot change singleton value.");
}
@Override
protected S initialValue() {
return _factory.create(Thread.currentThread());
}
/**
* Use by extended implementations to set value.
* @param value
*/
protected void reset(S value) {
super.set(value);
}
/**
* Singleton instance factory.
*
* @param <S> The singleton type.
*/
public interface ISingletonFactory<S> {
/**
* Create a new singleton instance.
*
* @param thread The thread the instance is being created for.
*/
S create(Thread thread);
}
}