/**
* Copyright 2008 Google Inc.
*
* 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.waveprotocol.wave.common.logging;
import java.util.Iterator;
import java.util.LinkedList;
/**
* A circular buffer implementation backed by a LinkedList.
*
* This is basically a linked list with a limit on the number of entries.
*
*
* @param <T>
*/
public class CircularBuffer<T> implements Iterable<T> {
private final LinkedList<T> data;
private final int maxSize;
/**
* Initializes a circular buffer with max size.
* @param maxSize
*/
public CircularBuffer(int maxSize) {
data = new LinkedList<T>();
this.maxSize = maxSize;
}
/**
* Returns the number of entries in the buffer.
*/
public int size() {
return data.size();
}
/**
* Adds an entry to the circular buffer. If the number of entries exceeds
* buffer capacity, the first added entry is replaced.
*
* @param e
*/
public void add(T e) {
data.addLast(e);
if (data.size() > maxSize) {
data.removeFirst();
}
}
/**
* {@inheritDoc}
*/
public Iterator<T> iterator() {
return data.iterator();
}
/**
* Clears the circular buffer.
*/
public void clear() {
data.clear();
}
}