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

package org.ozoneDB.DxLib;

import java.io.IOException;


class DxListNode extends DxObject {
    
    final static long serialVersionUID = 1L;
    
    Object _data;
    DxListNode _next;
    DxListNode _prev;
    
    
    public DxListNode() {
    }
    
    
    public DxListNode( Object obj ) {
        _data = obj;
    }
    
    
    public void storeBehind( DxListNode node ) {
        // if ((node._prev!=null)||(node._next!=null))
        //     warning ("DxListNode wird in zwei Listen gleichzeitig gespeichert");
        if (_next != null) {
            _next._prev = node;
        } 
        node._next = _next;
        node._prev = this;
        _next = node;
    } 
    
    
    public void storeInfront( DxListNode node ) {
        // if ((node._prev!=null)||(node._next!=null))
        //     ln ("\nWarnung: DxListNode wird in zwei Listen gleichzeitig gespeichert");
        if (_prev != null) {
            _prev._next = node;
        } 
        node._next = this;
        node._prev = _prev;
        _prev = node;
    } 
    
    
    public void remove() {
        if (_next != null) {
            _next._prev = _prev;
        } 
        if (_prev != null) {
            _prev._next = _next;
        } 
        _prev = _next = null;
    } 
    
    
    public DxListNode next() {
        return _next;
    } 
    
    
    public DxListNode prev() {
        return _prev;
    } 
    
    
    public Object data() {
        return _data;
    } 
}