XML解析以及增删改查的操作 2

import java.io.Serializable;
import java.util.List;
/**
 * xml文档节点基类，可以是普通节点，注释节点,文本节点
 * */
public abstract class Node implements Serializable,INodeAction{

    /**
     * 序列化版本号
     */
    private static final long serialVersionUID = 3858789701720999153L;
    /**
     * 父节点.规定 根节点的父节点为空
     * */
    protected Element father;
    /**
     * 由文档对象直接添加的节点 domFather赋值为document对象
     * */
    protected Document domFather;
    @Override
    public Integer getBeifen(){
        Integer n;
        if(father==null){
            n = 0;
            return n;
        }
        Node node = this;
        n = 0;
        while(node.father!=null){
            n++;
            node = node.father;
            if(node.father==null){
                return n;
            }
        }
        if(!(node.father==null)){
            return null;
        }
        return n;
    }
    
    public Element getFather() {
        return father;
    }
    @Override
    public String printSpace() {
        StringBuffer sb = new StringBuffer();
        Integer n = getBeifen();
        if (n == null) {
            return sb.toString();
        }
        for (int i = 0; i  nodeList = domFather.getNodeList();
                int idx = nodeList.indexOf(this);
                return idx==0?null:nodeList.get(idx-1);
            }
        }
        List<node> nodeList = father.getNodeList();
        int idx = nodeList.indexOf(this);
        return idx==0?null:nodeList.get(idx-1);
    }
    
    @Override
    public Node getNextSibling() {
        if(father==null){
            if(domFather==null){
                DocumentUtil.throwException("节点还没添加到文档！");
            }else{
                List<node> nodeList = domFather.getNodeList();
                int idx = nodeList.indexOf(this);
                return idx==nodeList.size()-1?null:nodeList.get(idx+1);
            }
        }
        List<node> nodeList = father.getNodeList();
        int idx = nodeList.indexOf(this);
        return idx==nodeList.size()-1?null:nodeList.get(idx+1);
    }
}</node></node></node>