/*

 * Copyright 2005-2008 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.net;

/**

 * This class represents a Network Interface address. In short it's an

 * IP address, a subnet mask and a broadcast address when the address is

 * an IPv4 one. An IP address and a network prefix length in the case

 * of IPv6 address.

 *

 * @see java.net.NetworkInterface

 * @since 1.6

 */

public class InterfaceAddress {

    private InetAddress address = null;

    private Inet4Address broadcast = null;

    private short        maskLength = 0;

    /*

     * Package private constructor. Can't be built directly, instances are

     * obtained through the NetworkInterface class.

     */

    InterfaceAddress() {

    }

    /**

     * Returns an <code>InetAddress</code> for this address.

     *

     * @return the <code>InetAddress</code> for this address.

     */

    public InetAddress getAddress() {

        return address;

    }

    /**

     * Returns an <code>InetAddress</code> for the brodcast address

     * for this InterfaceAddress.

     * <p>

     * Only IPv4 networks have broadcast address therefore, in the case

     * of an IPv6 network, <code>null</code> will be returned.

     *

     * @return the <code>InetAddress</code> representing the broadcast

     *         address or <code>null</code> if there is no broadcast address.

     */

    public InetAddress getBroadcast() {

        return broadcast;

    }

    /**

     * Returns the network prefix length for this address. This is also known

     * as the subnet mask in the context of IPv4 addresses.

     * Typical IPv4 values would be 8 (255.0.0.0), 16 (255.255.0.0)

     * or 24 (255.255.255.0). <p>

     * Typical IPv6 values would be 128 (::1/128) or 10 (fe80::203:baff:fe27:1243/10)

     *

     * @return a <code>short</code> representing the prefix length for the

     *         subnet of that address.

     */

     public short getNetworkPrefixLength() {

        return maskLength;

    }

    /**

     * Compares this object against the specified object.

     * The result is <code>true</code> if and only if the argument is

     * not <code>null</code> and it represents the same interface address as

     * this object.

     * <p>

     * Two instances of <code>InterfaceAddress</code> represent the same

     * address if the InetAddress, the prefix length and the broadcast are

     * the same for both.

     *

     * @param   obj   the object to compare against.

     * @return  <code>true</code> if the objects are the same;

     *          <code>false</code> otherwise.

     * @see     java.net.InterfaceAddress#hashCode()

     */

    public boolean equals(Object obj) {

        if (!(obj instanceof InterfaceAddress)) {

            return false;

        }

        InterfaceAddress cmp = (InterfaceAddress) obj;

        if ( !(address == null ? cmp.address == null : address.equals(cmp.address)) )

            return false;

        if ( !(broadcast  == null ? cmp.broadcast == null : broadcast.equals(cmp.broadcast)) )

            return false;

        if (maskLength != cmp.maskLength)

            return false;

        return true;

    }

    /**

     * Returns a hashcode for this Interface address.

     *

     * @return  a hash code value for this Interface address.

     */

    public int hashCode() {

        return address.hashCode() + ((broadcast != null) ? broadcast.hashCode() : 0) + maskLength;

    }

    /**

     * Converts this Interface address to a <code>String</code>. The

     * string returned is of the form: InetAddress / prefix length [ broadcast address ].

     *

     * @return  a string representation of this Interface address.

     */

    public String toString() {

        return address + "/" + maskLength + " [" + broadcast + "]";

    }

}