deathobject.java

Java的面向对象数据库系统的源代码

// You can redistribute this software and/or modify it under the terms of
// the Ozone Core License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-@year@ by SMB GmbH. All rights reserved.
//
// $Id$

package org.ozoneDB.core.storage.classicStore;

import org.ozoneDB.core.*;
import org.ozoneDB.core.storage.classicStore.ClassicObjectContainer;
import org.ozoneDB.core.storage.classicStore.ClassicStore;
import org.ozoneDB.core.storage.classicStore.ClusterID;
import org.ozoneDB.util.*;
import org.ozoneDB.DxLib.*;
import org.ozoneDB.OzoneCompatible;
import org.ozoneDB.io.stream.ResolvingObjectInputStream;

import java.io.*;


/**
 * Stellt einen eintrag in die objektliste des clusterspaces dar.
 * Obj is the object id of the ref. object.
 * Data der datenteil des objektes in byte form
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 */
public class DeathObject extends DxObject {
    public final static byte FREE = 0;
    public final static byte DELETED = 1;
    public final static byte FROZEN = 2;
    public final static byte CHANGED = 3;

    protected ObjectID oid;
    protected byte[] data;
    protected long size;
    /**
     * will be set while read the object state chunk (see
     * Cluster.readObjects() and Cluster.appendObject())
     */
    protected long stateSize;
    protected byte state = FREE;

    /** References for the double linked list */
    public DeathObject previous;
    public DeathObject next;


    public DeathObject() {
    }


    public DeathObject( ObjectID _oid ) {
        oid = _oid;
    }


    public final ObjectID objID() {
        return oid;
    }


    public final byte[] data() {
        return data;
    }


    public final void setData( byte[] _data ) {
        data = _data;
        setSize( data.length );
    }


    public final long size() {
        return size;
    }


    public final void setSize( long s ) {
        size = s;
    }


    public final byte state() {
        return state;
    }


    public final ClusterID clusterID() {
        return container().clusterID();
    }


    public final void setCluID( ClusterID _cid ) {
        container().setClusterID( _cid );
    }


    public final ClassicObjectContainer container() {
        return (ClassicObjectContainer)((ClassicStore)Env.currentEnv().getStoreManager()).objectSpace.objectForID( oid );
    }


    public final void setState( byte s ) {
        state = s;
        // Speicher freigeben, da DeathObject selbst nicht sofort aus dem
        // ClusterSpace geloescht wird, sondern in priorityQueue referenziert
        // wird.
        if (state == DELETED) {
            data = null;
            oid = null;
        }
    }


    public OzoneCompatible enlive() throws IOException {
        if (data != null) {
            try {
                //env.logWriter.newEntry ("enlive data size: " + data.length, LogWriter.DEBUG3);
                ByteArrayInputStream bs = new ByteArrayInputStream( data );
                ObjectInput in = new ResolvingObjectInputStream( bs );
                OzoneCompatible obj = (OzoneCompatible)in.readObject();
                in.close();
                bs.close();

                // NEW: if an object is activated, we don't need the data any longer
                data = null;

                return obj;
            } catch (Exception e) {
                Env.currentEnv().logWriter.newEntry( this, e.toString(), LogWriter.WARN );
                throw new IOException( e.toString() );
            }
        }
        return null;
    }
}