decoderloginmessage.java

利用mina框架写的一个通信实例。初学者的一个好教程。

/*
 *   @(#) $Id: AddMessageDecoder.java 357871 2005-12-20 01:56:40Z trustin $
 *
 *   Copyright 2004 The Apache Software Foundation
 *
 *   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.apache.mina.examples.call.decode;

import org.apache.mina.common.ByteBuffer;
import org.apache.mina.examples.call.Constants;
import org.apache.mina.examples.call.message.AbstractMessage;
import org.apache.mina.examples.call.message.LoginMessage;
import org.apache.mina.protocol.ProtocolSession;
import org.apache.mina.protocol.codec.MessageDecoder;

/**
 * A {@link MessageDecoder} that decodes {@link LoginMessage}.
 * 
 * @author The Apache Directory Project
 * @version $Rev: 357871 $, $Date: 2005-12-20 10:56:40 +0900 (Tue, 20 Dec 2005) $
 */
public class DecoderLoginMessage extends DecoderAbstractMessage {

	public DecoderLoginMessage() {
		super(Constants.TYPE_LOGIN);// login message;
	}

	protected AbstractMessage decodeBody(ProtocolSession session, ByteBuffer in) {
		//System.out.println("--info DecoderLoginMessage decodeBody begin");

		// set byte order
		in.order(Constants.BYTE_ORDER);

		if (in.remaining() < Constants.BODY_LEN_LOGIN) {
			return null;
		}

		LoginMessage message = new LoginMessage();
		message.setHead_len(this.head_len);
		message.setHead_command(this.head_command);
		message.setHead_sequence(this.head_sequence);

		// set user from byte buffer
		byte[] user = new byte[Constants.LOGIN_MESSAGE_BODY_USER_LENGTH];
		in.get(user);
		message.setUser(user);// byte[51]

		// set password
		byte[] Password = new byte[Constants.LOGIN_MESSAGE_BODY_PASSWORD_LENGTH];
		in.get(Password);
		message.setPassword(Password);// byte[21]

		// set direction/version
		message.setDirection(in.getInt());// int=4
		message.setVersion(in.getInt());// int=4

		// set comment
		byte[] Comment = new byte[Constants.LOGIN_MESSAGE_BODY_COMMENT_LENGTH];
		in.get(Comment);
		message.setComment(Comment);// byte[21]

		//System.out.println("--info DecoderLoginMessage decodeBody end");
		return message;
	}

}