关于一个同时遍历的问题

我写了一个图的遍历的
现在想加入多线程同时遍历并显示出时间
应该怎样加多线程跟如何写遍历的时间啊
求高手解决





import java.util.*;
import java.applet.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;


public class GraphTraverse
{


public static void main(String[] args)
{

  new JFrame4();
  Graph g = new Graph();
}
}
//用于实现深度优先搜索的栈类
class StackX
{
    private final int SIZE=20;
    private int[] st;
    private int top;
    public StackX(){
        st=new int[SIZE];
        top=-1;
    }
    public void push(int j){
        st[++top]=j;
    }
    public int pop(){
        return st[top--];
    }
    public int peek(){
        return st[top];
    }
    public boolean isEmpty(){
        return top==-1;
    }
}
//用于实现广度优先搜索的队列类
class Queue
{
    private final int SIZE=20;
    private int[] queArray;
    private int front;
    private int rear;
    public Queue(){
        queArray=new int[SIZE];
        front=0;
        rear=-1;
    }
    public void insert(int j){
        if(rear==SIZE-1)
            rear=-1;
        queArray[++rear]=j;
    }
    public int remove(){
        int temp=queArray[front++];
        if(front==SIZE)
            front=0;
        return temp;
    }
    public boolean isEmpty(){
        return ((rear+1==front)||(front+SIZE-1==rear));
    }
}
//顶点类
class Vertex
{
    public char label;
    public boolean wasVisited;
    public Vertex(char lab){
        label=lab;
        wasVisited=false;
    }
}
//图类
class Graph
{
String s1="";
String s="";
private final int MAX_VERTS=20;
    private Vertex vertexList[];
    private int adjMat[][];
    private int nVerts;
    private StackX theStack;
    private Queue theQueue;


    public Graph() {
        vertexList=new Vertex[MAX_VERTS];
        adjMat=new int[MAX_VERTS][MAX_VERTS];
        nVerts=0;
        for (int j = 0; j < MAX_VERTS; j++){
            for (int k = 0; k < MAX_VERTS; k++) {
                adjMat[j][k]=0;
            }
        }
        theStack=new StackX();
        theQueue=new Queue();
    }
    //增加一个顶点
    public void addVertex(char lab){
        vertexList[nVerts++]=new Vertex(lab);
    }
    //增加一条边
    public void addEdge(int start,int end){
        adjMat[start][end]=1;
        adjMat[end][start]=1;
    }
   public void displayVertex(int v)
   {
        s1=vertexList[v].label+"->";
        s=s+s1;
    }
    public String getStr()
    {

return s;


}

    //得到与v顶点邻接且未访问过的顶点标号
    public int getAdjUnvisitedVertex(int v){
        for (int j = 0; j < nVerts; j++) {
            if(adjMat[v][j]==1&&vertexList[j].wasVisited==false)
                return j;
        }
        return -1;
    }

    //深度
    public void dfs(){
s="";
        vertexList[0].wasVisited=true;
        displayVertex(0);
        theStack.push(0);
        while(!theStack.isEmpty()){
            int v=getAdjUnvisitedVertex(theStack.peek());
            if(v==-1)
                theStack.pop();
            else{
                vertexList[v].wasVisited=true;
                displayVertex(v);
                theStack.push(v);
            }
        }
        for(int j=0;j<nVerts;j++)
            vertexList[j].wasVisited=false;
    }



    //广度
    public void bfs(){
s="";
        vertexList[0].wasVisited=true;
        displayVertex(0);
        theQueue.insert(0);
        int v2;
        while(!theQueue.isEmpty()){
            int v1=theQueue.remove();
            while((v2=getAdjUnvisitedVertex(v1))!=-1){
                vertexList[v2].wasVisited=true;
                displayVertex(v2);
                theQueue.insert(v2);
            }
        }
        for (int j = 0; j < nVerts; j++) {
            vertexList[j].wasVisited=false;
        }
    }
}


class JFrame4 implements ActionListener
{
String s1="";
JPanel aw;
JPanel bw;
JPanel cw;
JPanel dw;
JPanel ew;


Graph g = new Graph();
JTextField text1;
JTextField text2;
JTextField text3;
JTextField text4;

public JFrame4()

{
  g.addVertex('a');
  g.addVertex('b');
  g.addVertex('c');
  g.addVertex('d');
  g.addVertex('e');
  g.addEdge(0,1);
  g.addEdge(0,2);
  g.addEdge(0,3);
  g.addEdge(1,4);
  g.addEdge(2,3);
  g.addEdge(2,4);






        aw=new JPanel();
        bw=new JPanel();
        cw=new JPanel();
        dw=new JPanel();
        ew=new JPanel();
text1=new JTextField(20);
text2=new JTextField(20);
text3=new JTextField(20);
text4=new JTextField(20);
        JFrame f = new JFrame("图");
        JButton b1 = new JButton("深度遍历");
        JButton b2 = new JButton("广度遍历");
        JButton b3 = new JButton("同时遍历并显示时间");
        cw.add(b3);
        dw.add(new Label("深度遍历时间;"));
        ew.add(new Label("广度遍历时间;"));
        dw.add(text3);
        ew.add(text4);
        b1.addActionListener(this);
        b2.addActionListener(this);
        b3.addActionListener(this);
        aw.add(b1);
        bw.add(b2);
        aw.add(text1);
        bw.add(text2);
        f.add(aw);
        f.add(bw);
        f.add(cw);
        f.add(dw);
        f.add(ew);
        f.setLayout(new FlowLayout());
        f.setBounds(400,300,400,400);
        //f.pack();
        f.setVisible(true);






     }

  public void actionPerformed(ActionEvent f)
  {
  String cmd=f.getActionCommand();
      if(cmd.equals("深度遍历"))
         {

  g.dfs();


  text1.setText(g.getStr());
  }



      if(cmd.equals("广度遍历"))
      {
  g.bfs();

          text2.setText(g.getStr());
      }






  }
}