storeditem.java

High performance DB query

/*
 * @(#)$Id: StoredItem.java,v 1.9 2005/06/17 21:15:26 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.provider.basic;

import services.network.Payload;
import util.BitID;
import util.FreeList;
import util.FreeListFactory;
import util.network.serialization.GenericByteBuffer;
import util.network.serialization.SerializationManager;
import util.network.serialization.SerializeBool;
import util.network.serialization.SerializeString;

/**
 * Class StoredItem
 *
 */
public class StoredItem implements Comparable, Payload {

    public static long serialVersionUID =
        SerializationManager.getSerialUID("overlay.provider.basic.StoredItem");
    public String ns;
    public String rid;
    public int iid;
    public Payload object;
    public double expiration;
    public BitID locationID;
    public BitID storageID;
    private static FreeList freeList = new FreeList(new StoredItemFactory());

    /**
     * DeSerialize the object from the provided GenericByteBuffer.
     *
     * @param inputBuffer
     */
    public StoredItem(GenericByteBuffer inputBuffer) {
        this.ns = SerializeString.deSerialize(inputBuffer);
        this.rid = SerializeString.deSerialize(inputBuffer);
        this.iid = inputBuffer.getInt();
        this.object = SerializationManager.deSerialize(inputBuffer);
        this.expiration = inputBuffer.getDouble();

        boolean nulls[] = SerializeBool.deSerialize(inputBuffer, 2);

        this.locationID = nulls[0]
                          ? null
                          : new BitID(inputBuffer);
        this.storageID = nulls[1]
                         ? null
                         : new BitID(inputBuffer);
    }

    /**
     * Serialize the object into the provided GenericByteBuffer.
     *
     * @param outputBuffer
     * @return
     */
    public long serialize(GenericByteBuffer outputBuffer) {
        SerializeString.serialize(outputBuffer, ns);
        SerializeString.serialize(outputBuffer, rid);
        outputBuffer.putInt(iid);
        SerializationManager.serialize(outputBuffer, object);
        outputBuffer.putDouble(expiration);
        SerializeBool.serialize(outputBuffer, (locationID == null),
                                (storageID == null));

        if (locationID != null) {
            locationID.serialize(outputBuffer);
        }

        if (storageID != null) {
            storageID.serialize(outputBuffer);
        }

        return serialVersionUID;
    }

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

    private void init(String ns, String rid, int iid, Payload object,
                      double expiration, BitID locationID, BitID storageID) {
        this.ns = ns;
        this.rid = rid;
        this.iid = iid;
        this.object = object;
        this.expiration = expiration;
        this.locationID = locationID;
        this.storageID = storageID;
    }

    /**
     * Method getSize
     * @return
     */
    public int getSize() {
        int size = ns.length() + rid.length() + Payload.INT_SIZE
                   + Payload.DOUBLE_SIZE;

        if (object != null) {
            size += SerializationManager.getPayloadSize(object);
        }

        return size;
    }

    /**
     * Method equals
     *
     * @param other
     * @return
     */
    public boolean equals(Object other) {
        StoredItem otherItem = (StoredItem) other;

        return (ns.equals(otherItem.ns) && rid.equals(otherItem.rid)
                && (iid == otherItem.iid));
    }

    /**
     * Method compareTo
     *
     * @param other
     * @return
     */
    public int compareTo(Object other) {
        StoredItem otherItem = (StoredItem) other;
        int nsCompare = ns.compareTo(otherItem.ns);

        if (nsCompare != 0) {
            return nsCompare;
        }

        int ridCompare = ns.compareTo(otherItem.rid);

        if (ridCompare != 0) {
            return ridCompare;
        }

        if (iid > otherItem.iid) {
            return 1;
        }

        if (iid < otherItem.iid) {
            return -1;
        }

        return 0;
    }

    /**
     * Method toString
     * @return
     */
    public String toString() {
        return "<StoredItem: NS:" + ns + ", RID: " + rid + ", IID: " + iid
               + ", EX: " + expiration + ">";
    }

    /**
     * Method allocate
     *
     * @param ns
     * @param rid
     * @param iid
     * @param object
     * @param expiration
     * @param locationID
     * @param storageID
     * @return
     */
    public static StoredItem allocate(String ns, String rid, int iid,
                                      Payload object, double expiration,
                                      BitID locationID, BitID storageID) {
        StoredItem theItem = (StoredItem) freeList.allocate();

        theItem.init(ns, rid, iid, object, expiration, locationID, storageID);

        return theItem;
    }

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


/**
 * Class StoredItemFactory
 *
 */
class StoredItemFactory implements FreeListFactory {

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