deathobject.java

用Java写的面相对象的数据库管理系统

// 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) 1997-2000 by SMB GmbH. All rights reserved.
//
// $Id: DeathObject.java,v 1.5 2000/10/28 16:55:17 daniela Exp $

package org.ozoneDB.core.classicStore;

import org.ozoneDB.core.*;
import org.ozoneDB.util.*;
import org.ozoneDB.DxLib.*;
import org.ozoneDB.OzoneCompatible;
import java.io.*;


/**
 * stellt einen eintrag in die objektliste des clusterspaces dar;
 * obj ist die objekt id des ref. objektes;
 * data der datenteil des objektes in byte form
 */
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().store).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 ObjectInputStream( 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;
    } 
}