PlayBuffer.java

/*
 * RED5 Open Source Flash Server - http://code.google.com/p/red5/
 * 
 * Copyright 2006-2012 by respective authors (see below). All rights reserved.
 * 
 * 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.red5.server.stream;

import java.util.LinkedList;
import java.util.Queue;

import org.red5.server.net.rtmp.event.IRTMPEvent;
import org.red5.server.stream.message.RTMPMessage;

/**
 * A Play buffer for sending VOD.
 * The implementation is not synchronized.
 * 
 * @author The Red5 Project (red5@osflash.org)
 * @author Steven Gong (steven.gong@gmail.com)
 */
public class PlayBuffer {
	
	/**
	 * Buffer capacity
	 */
	private long capacity;

	/**
	 * Message size
	 */
	private long messageSize;

	/**
	 * Queue of RTMP messages
	 */
	private Queue<RTMPMessage> messageQueue = new LinkedList<RTMPMessage>();

	/**
	 * Create play buffer with given capacity
	 * @param capacity          Capacity of buffer
	 */
	public PlayBuffer(long capacity) {
		this.capacity = capacity;
	}

	/**
	 * Buffer capacity in bytes.
	 * 
	 * @return          Buffer capacity in bytes
	 */
	public long getCapacity() {
		return capacity;
	}

	/**
	 * Setter for capacity
	 *
	 * @param capacity  New capacity
	 */
	public void setCapacity(long capacity) {
		this.capacity = capacity;
	}

	/**
	 * Number of messages in buffer.
	 * 
	 * @return          Number of messages in buffer
	 */
	public int getMessageCount() {
		return messageQueue.size();
	}

	/**
	 * Total message size in bytes.
	 * 
	 * @return          Total message size in bytes
	 */
	public long getMessageSize() {
		return messageSize;
	}

	/**
	 * Put a message into this buffer.
	 * 
	 * @param message          RTMP message
	 * @return <tt>true</tt> indicates success and <tt>false</tt>
	 * indicates buffer is full.
	 */
	public boolean putMessage(RTMPMessage message) {
		IRTMPEvent body = message.getBody();
		if (!(body instanceof IStreamData)) {
			throw new RuntimeException("Expected IStreamData but got " + body);
		}
		int size = ((IStreamData<?>) body).getData().limit();
		if (messageSize + size > capacity) {
			return false;
		}
		messageSize += size;
		messageQueue.offer(message);
		return true;
	}

	/**
	 * Take a message from this buffer. The message count decreases.
	 * 
	 * @return <tt>null</tt> if buffer is empty.
	 */
	public RTMPMessage takeMessage() {
		RTMPMessage message = messageQueue.poll();
		if (message != null) {
			IRTMPEvent body = message.getBody();
			if (!(body instanceof IStreamData)) {
				throw new RuntimeException("Expected IStreamData but got " + body);
			}
			messageSize -= ((IStreamData<?>) body).getData().limit();
		}
		return message;
	}

	/**
	 * Peek a message but not take it from the buffer. The message count
	 * doesn't change.
	 * @return <tt>null</tt> if buffer is empty.
	 */
	public RTMPMessage peekMessage() {
		return messageQueue.peek();
	}

	/**
	 * Empty this buffer.
	 */
	public void clear() {
		messageQueue.clear();
		messageSize = 0;
	}
}