update.java

High performance DB query

/*
 * @(#)$Id: Update.java,v 1.7 2004/07/02 23:59:20 huebsch Exp $
 *
 * Copyright (c) 2001-2004 Regents of the University of California.
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached BERKELEY-LICENSE
 * file. If you do not find these files, copies can be found by writing to:
 * Computer Science Division, Database Group, Universite of California,
 * 617 Soda Hall #1776, Berkeley, CA 94720-1776. Attention: Berkeley License
 *
 * Copyright (c) 2003-2004 Intel Corporation. All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE file.
 * If you do not find these files, copies can be found by writing to:
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300,
 * Berkeley, CA, 94704.  Attention:  Intel License Inquiry.
 */


package overlay.location.can.payload;

import java.net.InetSocketAddress;
import overlay.location.can.Zone;
import services.network.Payload;
import util.FreeList;
import util.FreeListFactory;
import util.network.serialization.GenericByteBuffer;
import util.network.serialization.SerializationManager;

/**
 * The class encapsulates an update message.  The update message refreshes the
 * receiver's view of the sender's zone.  It contains the sender's address, its
 * zone, and the current version of the zone.  The version number is incremented
 * by one every time a node changes zones, through a split or a
 * recombination.
 */
public class Update extends CANMessage {

    public static long serialVersionUID =
        SerializationManager.getSerialUID(
            "overlay.location.can.payload.Update");
    private Zone zone;
    private int version;
    private int deep;
    private int size;
    private static FreeList freeList = new FreeList(new UpdateFactory());

    /**
     * DeSerialize the object from the provided GenericByteBuffer.
     *
     * @param inputBuffer
     */
    public Update(GenericByteBuffer inputBuffer) {
        super(inputBuffer);

        this.zone = new Zone(inputBuffer);
        this.version = inputBuffer.getInt();
        this.deep = inputBuffer.getInt();
        this.size = computeSize();
    }

    /**
     * Serialize the object into the provided GenericByteBuffer.
     *
     * @param outputBuffer
     * @return
     */
    public long serialize(GenericByteBuffer outputBuffer) {
        super.serialize(outputBuffer);
        zone.serialize(outputBuffer);
        outputBuffer.putInt(version);
        outputBuffer.putInt(deep);

        return serialVersionUID;
    }

    /**
     * Constructor Update
     */
    protected Update() {}

    private void init(int messageID, InetSocketAddress source, Zone zone,
                      int version, int deep) {
        super.init(messageID, source);

        this.version = version;
        this.zone = zone;
        this.deep = deep;
        this.size = computeSize();
    }

    private int computeSize() {
        return super.getSize() + SerializationManager.getPayloadSize(zone)
               + Payload.INT_SIZE + Payload.INT_SIZE;
    }

    /**
     * Method getSize
     * @return
     */
    public int getSize() {
        return size;
    }

    /**
     * Method getZone
     * @return
     */
    public Zone getZone() {
        return zone;
    }

    /**
     * Method getVersion
     * @return
     */
    public int getVersion() {
        return version;
    }

    /**
     * Method getDepth
     * @return
     */
    public int getDepth() {
        return deep;
    }

    /**
     * Method allocate
     *
     * @param messageID
     * @param source
     * @param zone
     * @param version
     * @param deep
     * @return
     */
    public static Update allocate(int messageID, InetSocketAddress source,
                                  Zone zone, int version, int deep) {
        Update message = (Update) freeList.allocate();

        message.init(messageID, source, zone, version, deep);

        return message;
    }

    /**
     * Method free
     *
     * @param message
     */
    public static void free(Update message) {
        freeList.free(message);
    }
}


/**
 * Class UpdateFactory
 *
 */
class UpdateFactory implements FreeListFactory {

    /**
     * Method create
     * @return
     */
    public Object create() {
        return new Update();
    }
}