简易的Java树节点

今天在做一个计算BOM成本的功能，BOM是一个由物料组成的树，规则是如果一个节点有子节点，那么这个节点的成本就是所有子节点之和，做这个功能最直接的想法就是通过递归的方式实现，后面查看到DefaultMutableTreeNode类有个实例方法depthFirstEnumeration()，查询API知道这个方法返回一个枚举,该枚举是已深度优先的顺序遍历此节点为根的子树，于是想自己写个深度遍历的实现，不过代码逻辑还理解不到位，暂时想不出，后续再补上代码。

<pre name="code" class="java">package com.jaws.tree;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;

public class TreeNode {
private TreeNode parent = null;//父节点
private LinkedList<TreeNode> children = null;//子节点链表
private Object userObject = null;
private int depth = 0;
{
children = new LinkedList<TreeNode>();
}
public TreeNode(){

}

public TreeNode(Object userObject) {
// TODO Auto-generated constructor stub
this.userObject = userObject;
}

public void add(TreeNode newChild){
children.add(newChild);//添加到子节点链表中
newChild.setParent(this);//设置子节点的父节点
}

public TreeNode getChildAt(int childIndex){
if (childIndex<0||childIndex>this.children.size()-1) {
return null;
}else{
return children.get(childIndex);
}
}

public int getChildCount(){
return children.size();
}

public TreeNode getParent() {
return parent;
}

void setParent(TreeNode parent) {
this.parent = parent;
this.depth = parent.getDepth()+1;//设置本节点的深度
}

public Object getUserObject() {
return userObject;
}

public void setUserObject(Object userObject) {
this.userObject = userObject;
}

public int getDepth() {
return depth;
}

public boolean isRoot(){
if (parent==null) {
return true;
}else{
return false;
}
}

public boolean isLeaf(){
if (children == null) {
return true;
} else {
if (children.isEmpty()) {
return true;
} else {
return false;
}
}
}

/**
* 返回子节点链表的迭代器
* @return
*/
public Iterator<TreeNode> children(){
return this.children.iterator();
}

public java.util.List<TreeNode> getChildren(){
return this.getChildren();
}

@Override
public String toString() {
// TODO Auto-generated method stub
return userObject!=null ? userObject.toString() : "";
}

@Override
public int hashCode() {
// TODO Auto-generated method stub
return super.hashCode();
}
}