/*

 * Copyright 2000-2007 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;

import java.io.ObjectInputStream;

import java.io.IOException;

import java.io.InvalidObjectException;

/**

 *

 * This class implements an IP Socket Address (IP address + port number)

 * It can also be a pair (hostname + port number), in which case an attempt

 * will be made to resolve the hostname. If resolution fails then the address

 * is said to be <I>unresolved</I> but can still be used on some circumstances

 * like connecting through a proxy.

 * <p>

 * It provides an immutable object used by sockets for binding, connecting, or

 * as returned values.

 * <p>

 * The <i>wildcard</i> is a special local IP address. It usually means "any"

 * and can only be used for <code>bind</code> operations.

 *

 * @see java.net.Socket

 * @see java.net.ServerSocket

 * @since 1.4

 */

public class InetSocketAddress extends SocketAddress {

    /* The hostname of the Socket Address

     * @serial

     */

    private String hostname = null;

    /* The IP address of the Socket Address

     * @serial

     */

    private InetAddress addr = null;

    /* The port number of the Socket Address

     * @serial

     */

    private int port;

    private static final long serialVersionUID = 5076001401234631237L;

    private InetSocketAddress() {

    }

    /**

     * Creates a socket address where the IP address is the wildcard address

     * and the port number a specified value.

     * <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   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside the specified

     * range of valid port values.

     */

    public InetSocketAddress(int port) {

        this(InetAddress.anyLocalAddress(), port);

    }

    /**

     *

     * Creates a socket 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   addr    The IP address

     * @param   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside the specified

     * range of valid port values.

     */

    public InetSocketAddress(InetAddress addr, int port) {

        if (port < 0 || port > 0xFFFF) {

            throw new IllegalArgumentException("port out of range:" + port);

        }

        this.port = port;

        if (addr == null)

            this.addr = InetAddress.anyLocalAddress();

        else

            this.addr = addr;

    }

    /**

     *

     * Creates a socket address 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>

     * If there is a security manager, its <code>checkConnect</code> method

     * is called with the host name as its argument to check the permissiom

     * to resolve it. This could result in a SecurityException.

     * <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   hostname the Host name

     * @param   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside the range

     * of valid port values, or if the hostname parameter is <TT>null</TT>.

     * @throws SecurityException if a security manager is present and

     *                           permission to resolve the host name is

     *                           denied.

     * @see     #isUnresolved()

     */

    public InetSocketAddress(String hostname, int port) {

        if (port < 0 || port > 0xFFFF) {

            throw new IllegalArgumentException("port out of range:" + port);

        }

        if (hostname == null) {

            throw new IllegalArgumentException("hostname can't be null");

        }

        try {

            addr = InetAddress.getByName(hostname);

        } catch(UnknownHostException e) {

            this.hostname = hostname;

            addr = null;

        }

        this.port = port;

    }

    /**

     *

     * Creates an unresolved socket address from a hostname and a port number.

     * <p>

     * No attempt will be made to resolve the hostname into an InetAddress.

     * 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   host    the Host name

     * @param   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside

     *                  the range of valid port values, or if the hostname

     *                  parameter is <TT>null</TT>.

     * @see     #isUnresolved()

     * @return  a <code>InetSocketAddress</code> representing the unresolved

     *          socket address

     * @since 1.5

     */

    public static InetSocketAddress createUnresolved(String host, int port) {

        if (port < 0 || port > 0xFFFF) {

            throw new IllegalArgumentException("port out of range:" + port);

        }

        if (host == null) {

            throw new IllegalArgumentException("hostname can't be null");

        }

        InetSocketAddress s = new InetSocketAddress();

        s.port = port;

        s.hostname = host;

        s.addr = null;

        return s;

    }

    private void readObject(ObjectInputStream s)

        throws IOException, ClassNotFoundException {

        s.defaultReadObject();

        // Check that our invariants are satisfied

        if (port < 0 || port > 0xFFFF) {

            throw new InvalidObjectException("port out of range:" + port);

        }

        if (hostname == null && addr == null) {

            throw new InvalidObjectException("hostname and addr " +

                                             "can't both be null");

        }

    }

    /**

     * Gets the port number.

     *

     * @return the port number.

     */

    public final int getPort() {

        return port;

    }

    /**

     *

     * Gets the <code>InetAddress</code>.

     *

     * @return the InetAdress or <code>null</code> if it is unresolved.

     */

    public final InetAddress getAddress() {

        return addr;

    }

    /**

     * Gets the <code>hostname</code>.

     * Note: This method may trigger a name service reverse lookup if the

     * address was created with a literal IP address.

     *

     * @return  the hostname part of the address.

     */

    public final String getHostName() {

        if (hostname != null)

            return hostname;

        if (addr != null)

            return addr.getHostName();

        return null;

    }

    /**

     * Returns the hostname, or the String form of the address if it

     * doesn't have a hostname (it was created using a literal).

     * This has the benefit of <b>not</b> attemptimg a reverse lookup.

     *

     * @return the hostname, or String representation of the address.

     * @since 1.7

     */

    public final String getHostString() {

        if (hostname != null)

            return hostname;

        if (addr != null) {

            if (addr.hostName != null)

                return addr.hostName;

            else

                return addr.getHostAddress();

        }

        return null;

    }

    /**

     * Checks whether the address has been resolved or not.

     *

     * @return <code>true</code> if the hostname couldn't be resolved into

     *          an <code>InetAddress</code>.

     */

    public final boolean isUnresolved() {

        return addr == null;

    }

    /**

     * 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() {

        if (isUnresolved()) {

            return hostname + ":" + port;

        } else {

            return addr.toString() + ":" + port;

        }

    }

    /**

     * 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 address as

     * this object.

     * <p>

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

     * address if both the InetAddresses (or hostnames if it is unresolved) and port

     * numbers are equal.

     * If both addresses are unresolved, then the hostname & the port number

     * are compared.

     *

     * Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are

     * considered equal.

     *

     * @param   obj   the object to compare against.

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

     *          <code>false</code> otherwise.

     * @see java.net.InetAddress#equals(java.lang.Object)

     */

    public final boolean equals(Object obj) {

        if (obj == null || !(obj instanceof InetSocketAddress))

            return false;

        InetSocketAddress sockAddr = (InetSocketAddress) obj;

        boolean sameIP = false;

        if (this.addr != null)

            sameIP = this.addr.equals(sockAddr.addr);

        else if (this.hostname != null)

            sameIP = (sockAddr.addr == null) &&

                this.hostname.equalsIgnoreCase(sockAddr.hostname);

        else

            sameIP = (sockAddr.addr == null) && (sockAddr.hostname == null);

        return sameIP && (this.port == sockAddr.port);

    }

    /**

     * Returns a hashcode for this socket address.

     *

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

     */

    public final int hashCode() {

        if (addr != null)

            return addr.hashCode() + port;

        if (hostname != null)

            return hostname.toLowerCase().hashCode() + port;

        return port;

    }

}