/*
* Copyright (c) 2009-2010 Lockheed Martin Corporation
*
* 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 org.eurekastreams.commons.server;
import java.util.List;
/**
* Round robin through collection of items.
*
* @param <T>
* Type of items.
*/
public class RoundRobinRotator<T> implements Rotator<T>
{
/**
* List of item to rotate through.
*/
private List<T> items;
/**
* Size of list.
*/
private int size;
/**
* Running index.
*/
private int index;
/**
* Sync lock object.
*/
private Object lock = new Object();
/**
* Constructor.
*
* @param inItems
* List of item to rotate through.
*/
public RoundRobinRotator(final List<T> inItems)
{
items = inItems;
size = items.size();
index = 0;
}
/**
* Round robin through collection of items.
*
* @return Next item.
*/
@Override
public T getNext()
{
synchronized (lock)
{
T result = items.get(index);
index = ++index == size ? 0 : index;
return result;
}
}
}