dxhashiterator.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: DxHashIterator.java,v 1.5 2000/10/28 16:55:14 daniela Exp $

package org.ozoneDB.DxLib;

import java.io.*;
import java.util.*;

/**
 * 
 * 
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.5 $Date: 2000/10/28 16:55:14 $
 */
public final class DxHashIterator extends DxAbstractIterator {
    
    final static long serialVersionUID = 1L;
    
    Enumeration keyEnum;
    Enumeration objEnum;
    Object currentKey;
    Object currentObject;
    Hashtable ht;
    
    
    /**
     */
    public DxHashIterator( DxHashCollection _coll ) {
        ht = _coll.internalHashtable();
        reset();
    }
    
    
    /**
     */
    public Object object() {
        return currentObject;
    } 
    
    
    /**
     */
    public Object key() {
        return currentKey;
    } 
    
    
    /**
     */
    public Object next() {
        if (atFirstObject) {
            atFirstObject = false;
        } else {
            if (objEnum.hasMoreElements()) {
                currentObject = objEnum.nextElement();
                currentKey = keyEnum.nextElement();
            } else {
                return null;
            } 
        } 
        return object();
    } 
    
    
    /**
     */
    public void reset() {
        atFirstObject = true;
        objectRemoved = false;
        keyEnum = ht.keys();
        objEnum = ht.elements();
        if (objEnum.hasMoreElements()) {
            currentObject = objEnum.nextElement();
        } 
        if (keyEnum.hasMoreElements()) {
            currentKey = keyEnum.nextElement();
        } 
    } 
    
    
    /**
     */
    public synchronized Object removeObject() {
        return ht.remove( currentKey );
    } 
}