ozoneodmg.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 Library 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: OzoneODMG.java,v 1.10 2000/10/28 16:55:19 daniela Exp $

package org.ozoneDB.odmg;

import java.io.*;
import org.odmg.*;
import org.ozoneDB.DxLib.*;


/**
 * Implementation of the ODMG {@link Implementation} interface.
 * 
 * 
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.10 $Date: 2000/10/28 16:55:19 $
 */
public class OzoneODMG extends ODMG {
    
    /**
     * All {@link OzoneDatabase} objects that are created by this factory and
     * that currently are open.
     */
    private transient DxSet dbs;
    
    
    public OzoneODMG() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        dbs = new DxHashSet();
    }
    
    
    /**
     * Create a new <code>Database</code> object.
     * @return The new <code>Database</code> object.
     * @see org.odmg.Database
     */
    public synchronized Database newDatabase() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        Database db = new OzoneODMGDatabase( this );
        return db;
    } 
    
    
    /**
     * This method is called by the database objects to inform their factory
     * that another database actually has been opened.
     */
    protected synchronized void databaseOpened( Database db ) {
        // don't allow more than one database per factory; the code to support
        // this is there but this feature avoid determine the database of a
        // given thread which is important for the enhanced ozone version of
        // the ODMG Implementation interface
        if (dbs.count() > 0) {
            throw new ODMGRuntimeException( "More than one open databases per factory are not allowed." );
        } 
        
        dbs.add( db );
    } 
    
    
    protected synchronized void databaseClosed( Database db ) {
        dbs.remove( db );
    } 
    
    
    /**
     * Get the <code>Database</code> that contains the object <code>obj</code>.
     * @param obj The object.
     * @return The <code>Database</code> that contains the object.
     */
    public Database getDatabase( Object obj ) {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        
        DxIterator it = dbs.iterator();
        while (it.next() != null) {
            OzoneODMGDatabase db = (OzoneODMGDatabase)it.object();
            if (db.containsObject( obj )) {
                return db;
            } 
        } 
        return null;
    } 
    
    
    /**
     * Create a <code>Transaction</code> object and associate it with the
     * current thread.
     * @return The newly created <code>Transaction</code> instance.
     * @see org.odmg.Transaction
     */
    public Transaction newTransaction() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        return new OzoneODMGTransaction( dbs );
    } 
    
    
    /**
     * Get the current <code>Transaction</code> for the thread.
     * @return The current <code>Transaction</code> object or null if there is none.
     * @see org.odmg.Transaction
     */
    public Transaction currentTransaction() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        return OzoneODMGTransaction.current();
    } 
    
    
    /**
     * Get a <code>String</code> representation of the object's identifier.
     * @param obj The object whose identifier is being accessed.
     * @return The object's identifier in the form of a String
     */
    public String getObjectId( Object obj ) {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        
        throw new RuntimeException( "Method not implemented yet." );
    } 
    
    
    /**
     * Create a new <code>OQLQuery</code> object.
     * @return The new <code>OQLQuery</code> object.
     * @see org.odmg.OQLQuery
     */
    public OQLQuery newOQLQuery() {
        throw new RuntimeException( "newOQLQuery(): ozone does not implement OQL." );
    } 
    
    
    /**
     * Create a new <code>DList</code> object.
     * @return The new <code>DList</code> object.
     * @see org.odmg.DList
     */
    public DList newDList() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        return new OzoneODMGDList();
    } 
    
    
    /**
     * Create a new <code>DBag</code> object.
     * @return The new <code>DBag</code> object.
     * @see org.odmg.DBag
     */
    public DBag newDBag() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        return new OzoneODMGDBag();
    } 
    
    
    /**
     * Create a new <code>DSet</code> object.
     * @return The new <code>DSet</code> object.
     * @see org.odmg.DSet
     */
    public DSet newDSet() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        return new OzoneODMGDSet();
    } 
    
    
    /**
     * Create a new <code>DArray</code> object.
     * @return The new <code>DArray</code> object.
     * @see org.odmg.DArray
     */
    public DArray newDArray() {
        if (org.ozoneDB.core.Env.currentEnv() != null) {
            throw new ODMGRuntimeException( "Method must not be called from inside an ozone database object." );
        } 
        return new OzoneODMGDArray();
    } 
    
    
    /**
     * Create a new <code>DMap</code> object.
     * @return	The new <code>DMap</code> object.
     * @see org.odmg.DMap
     */
    public DMap newDMap() {
        throw new RuntimeException( "Method not implemented yet" );
    } 
    
}