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

package org.ozoneDB.DxLib;

/**
 * 
 * 
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.5 $Date: 2000/10/28 16:55:14 $
 */
public class DxMultiIterator extends DxAbstractIterator {
    
    final static long serialVersionUID = 1L;
    
    DxMultiMap multiMap;
    DxIterator mapIt;
    DxIterator contIt;
    
    
    /**
     */
    public DxMultiIterator( DxMultiMap _multiMap ) {
        multiMap = _multiMap;
        reset();
    }
    
    
    /**
     */
    public Object object() {
        return contIt != null ? contIt.object() : null;
    } 
    
    
    /**
     */
    public Object key() {
        return mapIt != null ? mapIt.key() : null;
    } 
    
    
    /**
     */
    public Object next() {
        Object obj = contIt != null ? contIt.next() : null;
        if (obj == null) {
            contIt = null;
            if (mapIt != null && mapIt.next() != null) {
                contIt = ((DxCollection)mapIt.object()).iterator();
                obj = contIt.next();
            } else {
                mapIt = null;
            } 
        } 
        return obj;
    } 
    
    
    /**
     */
    public void reset() {
        mapIt = multiMap.iterator();
        if (mapIt.next() != null) {
            contIt = ((DxCollection)mapIt.object()).iterator();
        } else {
            mapIt = null;
        } 
    } 
    
    
    /**
     */
    public Object removeObject() {
        Object obj = null;
        if (contIt != null) {
            obj = contIt.removeObject();
            multiMap.multiItemCount--;
            if (((DxCollection)mapIt.object()).isEmpty()) {
                contIt = null;
                mapIt.removeObject();
            } 
        } 
        return obj;
    } 
}