dxtreemap.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: DxTreeMap.java,v 1.7 2000/10/28 16:55:14 daniela Exp $

package org.ozoneDB.DxLib;

import java.io.*;

/**
 * A DxMap implementation that is based on a weight balanced tree.
 * 
 * 
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.7 $Date: 2000/10/28 16:55:14 $
 */
public class DxTreeMap extends DxAbstractMap implements DxTreeCollection, Externalizable {
    
    final static long serialVersionUID = 1L;
    
    protected transient DxBBTree bbtree;
    
    protected DxComparator comparator = null;
    
    
    public DxTreeMap() {
        comparator = new DxStandardComparator();
        bbtree = new DxBBTree( comparator );
    }
    
    
    public DxTreeMap( DxComparator _comparator ) {
        comparator = _comparator;
        bbtree = new DxBBTree( comparator );
    }
    
    
    public Object clone() {
        DxMap newMap = new DxTreeMap( comparator );
        return clone( newMap );
    } 
    
    
    /**
     */
    public synchronized boolean addForKey( Object obj, Object key ) {
        return bbtree.addForKey( obj, key );
    } 
    
    
    /**
     */
    public Object elementForKey( Object key ) {
        return bbtree.elementForKey( key );
    } 
    
    
    /**
     */
    public Object keyForElement( Object obj ) {
        return bbtree.keyForElement( obj );
    } 
    
    
    /**
     */
    public synchronized Object removeForKey( Object key ) {
        return bbtree.removeForKey( key );
    } 
    
    
    /**
     */
    public synchronized boolean remove( Object obj ) {
        Object key = keyForElement( obj );
        if (key != null) {
            removeForKey( key );
            return true;
        } 
        return false;
    } 
    
    
    /**
     */
    public DxIterator iterator() {
        return new DxBBIterator( this );
    } 
    
    
    /**
     */
    public int count() {
        return bbtree.count();
    } 
    
    
    /**
     */
    public boolean isEmpty() {
        return bbtree.isEmpty();
    } 
    
    
    /**
     */
    public boolean containsKey( Object key ) {
        return bbtree.containsKey( key );
    } 
    
    
    /**
     */
    public synchronized void clear() {
        bbtree = new DxBBTree( comparator );
    } 
    
    
    /**
     */
    public DxBBTree internalTree() {
        return bbtree;
    } 
    
    
    public void writeExternal( ObjectOutput out ) throws IOException {
        // System.out.println (getClass().getName() + ".writeExternal()...");
        out.writeObject( comparator );
        super.writeExternal( out );
    } 
    
    
    public synchronized void readExternal( ObjectInput in ) throws IOException, ClassNotFoundException {
        // System.out.println ("tree.readExternal()...");
        comparator = (DxComparator)in.readObject();
        bbtree = new DxBBTree( comparator );
        super.readExternal( in );
    } 
}