dxabstractbag.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: DxAbstractBag.java,v 1.6 2000/10/28 16:55:14 daniela Exp $

package org.ozoneDB.DxLib;


/**
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.6 $Date: 2000/10/28 16:55:14 $
 */
public abstract class DxAbstractBag extends DxAbstractCollection implements DxBag {
    
    final static long serialVersionUID = 1L;
    
    
    public DxAbstractBag() {
    }
    
    
    /**
     * Compares two bags for equality. Returns true, if obj is also a DxBag,
     * both bags have the same size and it contains all elements in the same
     * order as the receiver.
     */
    public boolean equals( Object obj ) {
        if (obj instanceof DxBag && obj != null) {
            DxBag rhs = (DxBag)obj;
            
            if (this == obj) {
                return true;
            } 
            if (count() != rhs.count()) {
                return false;
            } 
            
            DxIterator it = iterator();
            DxIterator it2 = rhs.iterator();
            Object cursor;
            Object cursor2;
            while ((cursor = it.next()) != null && (cursor2 = it2.next()) != null) {
                if (!cursor.equals( cursor2 )) {
                    return false;
                } 
            } 
            return true;
        } else {
            return false;
        } 
    } 
    
    
    public synchronized boolean add( Object obj ) {
        return addBack( obj );
    } 
    
    
    public synchronized boolean addBack( Object obj ) {
        throw new RuntimeException( "" );
    } 
    
}