PC World Komputer 1998 July & August/Pcwk78a98.iso/Internet/Javadraw/DATA.Z/DatagramPacket.java

Text File | 1997-08-30 | 5KB | 178 lines

/*
 * @(#)DatagramPacket.java    1.12 97/01/25
 *
 * Copyright (c) 1995, 1996 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Sun.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * CopyrightVersion 1.1_beta
 *
 */

package java.net;

/**
 * This class represents a datagram packet.
 * <p>
 * Datagram packets are used to implement a connectionless packet
 * delivery service. Each message is routed from one machine to
 * another based solely on information contained within that packet.
 * Multiple packets sent from one machine to another might be routed
 * differently, and might arrive in any order.
 *
 * @author  Pavani Diwanji
 * @version 1.12, 01/25/97
 * @since   JDK1.0
 */
public final
class DatagramPacket {
    /*
     * The fields of this class are package-private since DatagramSocketImpl
     * classes needs to access them.
     */
    byte[] buf;
    int length;
    InetAddress address;
    int port;

    /**
     * Constructs a <code>DatagramPacket</code> for receiving packets of
     * length <code>ilength</code>.
     * <p>
     * The <code>length</code> argument must be less than or equal to
     * <code>ibuf.length</code>.
     *
     * @param   ibuf      buffer for holding the incoming datagram.
     * @param   ilength   the number of bytes to read.
     * @since   JDK1.0
     */
    public DatagramPacket(byte ibuf[], int ilength) {
    if (ilength > ibuf.length) {
        throw new IllegalArgumentException("illegal length");
    }
    buf = ibuf;
    length = ilength;
    address = null;
    port = -1;
    }

    /**
     * Constructs a datagram packet for sending packets of length
     * <code>ilength</code> to the specified port number on the specified
     * host. The <code>length</code> argument must be less than or equal
     * to <code>ibuf.length</code>.
     *
     * @param   ibuf      the packet data.
     * @param   ilength   the packet length.
     * @param   iaddr     the destination address.
     * @param   iport     the destination port number.
     * @see     java.net.InetAddress
     * @since   JDK1.0
     */
    public DatagramPacket(byte ibuf[], int ilength,
              InetAddress iaddr, int iport) {
    if (ilength > ibuf.length) {
        throw new IllegalArgumentException("illegal length");
    }
    if (iport < 0 || iport > 0xFFFF) {
        throw new IllegalArgumentException("Port out of range:"+ iport);
    }
    buf = ibuf;
    length = ilength;
    address = iaddr;
    port = iport;
    }

    /**
     * Returns the IP address of the machine to which this datagram is being
     * sent or from which the datagram was received.
     *
     * @return  the IP address of the machine to which this datagram is being
     *          sent or from which the datagram was received.
     * @see     java.net.InetAddress
     * @since   JDK1.0
     */
    public synchronized InetAddress getAddress() {
    return address;
    }

    /**
     * Returns the port number on the remote host to which this datagram is
     * being sent or from which the datagram was received.
     *
     * @return  the port number on the remote host to which this datagram is
     *          being sent or from which the datagram was received.
     * @since   JDK1.0
     */
    public synchronized int getPort() {
    return port;
    }

    /**
     * Returns the data received or the data to be sent.
     *
     * @return  the data received or the data to be sent.
     * @since   JDK1.0
     */
    public synchronized byte[] getData() {
    return buf;
    }

    /**
     * Returns the length of the data to be sent or the length of the
     * data received.
     *
     * @return  the length of the data to be sent or the length of the
     *          data received.
     * @since   JDK1.0
     */
    public synchronized int getLength() {
    return length;
    }

    /**
     * @since   JDK1.1
     */
    public synchronized void setAddress(InetAddress iaddr) {
    address = iaddr;
    }

    /**
     * @since   JDK1.1
     */
    public synchronized void setPort(int iport) {
    if (iport < 0 || iport > 0xFFFF) {
        throw new IllegalArgumentException("Port out of range:"+ iport);
    }
    port = iport;
    }

    /**
     * @since   JDK1.1
     */
    public synchronized void setData(byte[] ibuf) {
    buf = ibuf;
    }

    /**
     * @since   JDK1.1
     */
    public synchronized void setLength(int ilength) {
    if (ilength > buf.length) {
        throw new IllegalArgumentException("illegal length");
    }
    length = ilength;
    }
}