username.java

解决了nat穿越的问题

/*
 * This file is part of JSTUN. 
 * 
 * Copyright (c) 2005 Thomas King <[e-mail]> - All rights
 * reserved.
 * 
 * This software is licensed under either the GNU Public License (GPL),
 * or the Apache 2.0 license. Copies of both license agreements are
 * included in this distribution.
 */

package de.javawi.jstun.attribute;

import de.javawi.jstun.util.Utility;
import de.javawi.jstun.util.UtilityException;

public class Username extends MessageAttribute {
	String username;
	
	public Username() {
		super(MessageAttribute.MessageAttributeType.Username);
	}
	
	public Username(String username) {
		super(MessageAttribute.MessageAttributeType.Username);
		setUsername(username);
	}
	
	public String getUsername() {
		return username;
	}
	
	public void setUsername(String username) {
		this.username = username;
	}
	
	public byte[] getBytes() throws UtilityException {
		int length = username.length();
		// username header
		if ((length % 4) != 0) {
			length += 4 - (length % 4);
		}
		// message attribute header
		length += 4;
		byte[] result = new byte[length];
		// message attribute header
		// type
		System.arraycopy(Utility.IntegerToTwoBytes(typeToInteger(type)), 0, result, 0, 2);
		// length
		System.arraycopy(Utility.IntegerToTwoBytes(length-4), 0, result, 2, 2);
		
		// username header
		byte[] temp = username.getBytes();
		System.arraycopy(temp, 0, result, 4, temp.length);
		return result;
	}
	
	public static Username parse(byte[] data) {
		Username result = new Username();
		String username = new String(data);
		result.setUsername(username);
		return result;
	}
}