stunaddress.java

stun的java实现

/*
 * Stun4j, the OpenSource Java Solution for NAT and Firewall Traversal.
 *
 * Distributable under LGPL license.
 * See terms of license at gnu.org.
 */
package net.java.stun4j;

import java.net.InetSocketAddress;
import java.net.InetAddress;
import java.net.*;

/**
 * The Address class is used to define destinations to outgoing Stun Packets.
 *
 * <p>Organisation: <p> Louis Pasteur University, Strasbourg, France</p>
 * <p>Network Research Team (http://www-r2.u-strasbg.fr)</p></p>
 * @author Emil Ivov
 * @version 0.1
 */

public class StunAddress
{
    InetSocketAddress socketAddress = null;

    /**
     * Creates an address instance address from an IP address and a port number.
     * <p>
     * A valid port value is between 0 and 65535.
     * A port number of <code>zero</code> will let the system pick up an
     * ephemeral port in a <code>bind</code> operation.
     * <P>
     * A <code>null</code> address will assign the <i>wildcard</i> address.
     * <p>
     * @param	hostname	The IP address
     * @param	port	    The port number
     * @throws IllegalArgumentException if the port parameter is outside the
     * specified range of valid port values.
     */
    public StunAddress(String hostname, int port)
    {
        socketAddress = new InetSocketAddress(hostname, port);
    }

    /**
     * Creates an address instance address from a byte array containing an IP
     * address and a port number.
     * <p>
     * A valid port value is between 0 and 65535.
     * A port number of <code>zero</code> will let the system pick up an
     * ephemeral port in a <code>bind</code> operation.
     * <P>
     * A <code>null</code> address will assign the <i>wildcard</i> address.
     * <p>
     * @param	ipAddress The IP address
     * @param	port      The port number
     * @throws IllegalArgumentException if the port parameter is outside the
     * specified range of valid port values or if ipAddress is not a valid ip
     * address.
     */
    public StunAddress(byte[] ipAddress, int port)
    {

        try
        {
            socketAddress = new InetSocketAddress(InetAddress.getByAddress(
                ipAddress), port);
        }
        catch (UnknownHostException ex)
        {
            //Unknown Host - Let's skip resolution
            socketAddress = new InetSocketAddress((ipAddress[0]&0xFF) + "."
                                                   +(ipAddress[1]&0xFF) + "."
                                                   +(ipAddress[2]&0xFF) + "."
                                                   +(ipAddress[3]&0xFF) + ".",
                                                   port);
        }
    }


    /**
     * Creates an address instance from a hostname and a port number.
     * <p>
     * An attempt will be made to resolve the hostname into an InetAddress.
     * If that attempt fails, the address will be flagged as <I>unresolved</I>.
     * <p>
     * A valid port value is between 0 and 65535.
     * A port number of <code>zero</code> will let the system pick up an
     * ephemeral port in a <code>bind</code> operation.
     * <P>
     * @param	address the address itself
     * @param	port	the port number
     * @throws IllegalArgumentException if the port parameter is outside the
     * range of valid port values, or if the hostname parmeter is <TT>null</TT>.
     */
    public StunAddress(InetAddress address, int port)
    {
        socketAddress = new InetSocketAddress(address, port);
    }

    /**
     * Creates an address instance from the localhost amd a port number.
     * <p>
     * Addresses created with this constructor should be used cautiously as
     * they won't be trated as equal to address created from the localhost
     * address even though the represent the same thing. In other words - use
     * this constructor only if you're not going to compare the resulting
     * instance with other addresses.
     *
     * @param	port	the port number
     * @throws IllegalArgumentException if the port parameter is outside the
         * range of valid port values, or if the hostname parmeter is <TT>null</TT>.
     */
    public StunAddress(int port)
    {
        socketAddress = new InetSocketAddress(port);
    }


    /**
     * Returns the raw IP address of this Address object. The result is in
     * network byte order: the highest order byte of the address is in
     * getAddress()[0].
     * @return the raw IP address of this object.
     */
    public byte[] getAddressBytes()
    {
        return (socketAddress == null
                   ?null
                   :socketAddress.getAddress().getAddress());
    }

    /**
     * Returns the port number or 0 if the addres has not been initialized.
     * @return the port number.
     */
    public char getPort()
    {
        return (socketAddress == null
                   ?0
                   :(char)socketAddress.getPort());
    }

    /**
     * Returns the encapsulated InetSocketAddress instance.
     * @return the encapsulated InetSocketAddress instance.
     */
    public InetSocketAddress getSocketAddress()
    {
        return socketAddress;
    }

    /**
     * Constructs a string representation of this InetSocketAddress. This String
     * is constructed by calling toString() on the InetAddress and concatenating
     * the port number (with a colon). If the address is unresolved then the
     * part before the colon will only contain the hostname.
     *
     * @return a string representation of this object.
     */
    public String toString()
    {
        return socketAddress.toString();
    }

    /**
     * Compares this object against the specified object. The result is true if
     * and only if the argument is not null and it represents the same address
     * as this object.
     * <p/>
     * Two instances of InetSocketAddress represent the same address if both the
     * InetAddresses (or hostnames if it is unresolved) and port numbers are
     * equal.
     * <p/>
     * If both addresses are unresolved, then the hostname & the port number are
     * compared.
     * @param obj the object to compare against.
     * @return true if the objects are the same; false otherwise.
     */
    public boolean equals(Object obj)
    {
        if(!(obj instanceof StunAddress))
            return false;

        StunAddress target = (StunAddress)obj;
        if(   target.socketAddress == null
           && socketAddress ==null)
            return true;

        return socketAddress.equals(target.getSocketAddress());
    }

    /**
     * Gets the hostname.
     * @return the hostname part of the address
     */
    public String getHostName()
    {
        return socketAddress.getHostName();
    }
}