/*
 * Copyright (C) 2005 Alfresco, Inc.
 *
 * Licensed under the Mozilla Public License version 1.1 
 * with a permitted attribution clause. You may obtain a
 * copy of the License at
 *
 *   http://www.alfresco.org/legal/license.txt
 *
 * 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.alfresco.filesys.server;

import java.io.*;
import java.net.*;

/**
 * Java Socket Based Packet Handler Class
 * 
 * @author GKSpencer
 */
public abstract class SocketPacketHandler implements PacketHandlerInterface {

	//	Socket to read/write to/from

	private Socket m_socket;

	// Input/output streams for receiving/sending data

	private DataInputStream m_in;
	private DataOutputStream m_out;

	/**
	 * Class constructor
	 * 
	 * @param socket Socket
	 * @param protocol String
	 * @exception IOException
	 */
	protected SocketPacketHandler(Socket socket) throws IOException {
		m_socket = socket;

		//	Open the input/output streams

		m_in = new DataInputStream(m_socket.getInputStream());
		m_out = new DataOutputStream(m_socket.getOutputStream());
	}

	/**
	 * Return the protocol name
	 * 
	 * @return String
	 */
	public abstract String getProtocolName();

	/**
	 * Return the number of bytes available for reading without blocking
	 * 
	 * @return int
	 * @exception IOException
	 */
	public int availableBytes() throws IOException {
		if (m_in != null)
			return m_in.available();
		return 0;
	}

	/**
	 * Read a packet of data
	 * 
	 * @param pkt byte[]
	 * @param offset int
	 * @param maxLen int
	 * @return int
	 * @exception IOException
	 */
	public int readPacket(byte[] pkt, int offset, int maxLen) throws IOException {

		//	Read a packet of data

		if (m_in != null)
			return m_in.read(pkt, offset, maxLen);
		return 0;
	}

	/**
	 * Write a packet of data
	 * 
	 * @param pkt byte[]
	 * @param offset int
	 * @param len int
	 * @exception IOException
	 */
	public void writePacket(byte[] pkt, int offset, int len) throws IOException {

		//	Output the raw packet

		if (m_out != null) {

			synchronized (m_out) {
				m_out.write(pkt, offset, len);
			}
		}
	}

	/**
	 * Close the packet handler
	 */
	public void closePacketHandler() {

		//	Close the socket

		if (m_socket != null) {
			try {
				m_socket.close();
			} catch (Exception ex) {
			}
			m_socket = null;
		}

		//	Close the input stream

		if (m_in != null) {
			try {
				m_in.close();
			} catch (Exception ex) {
			}
			m_in = null;
		}

		//	Close the output stream

		if (m_out != null) {
			try {
				m_out.close();
			} catch (Exception ex) {
			}
			m_out = null;
		}
	}

	/**
	 * Return the socket
	 * 
	 * @return Socket
	 */
	protected final Socket getSocket() {
		return m_socket;
	}
}