多線程之Single Threaded Execution design pattern(單線程執行設計模式)

一次只讓一個線程進入

public class Userr extends  Thread {
     private final String  myname;
     private final String myaddress;
     private final Gate gate;
     
     public Userr(String myname,String myaddress,Gate gate){
         this.myname=myname;
         this.myaddress=myaddress;
         this.gate=gate;
     }
    @Override
    public void run(){
     System.out.println("我的名字:"+myname);
     //方便看到效果
     while (true){
         this.gate.pass(myname,myaddress);
       }
    }
}

public class Gate {
    private static int counter= 0;
    private String name="Nobody";
    private String address="Nowhere";
    //對屬性賦值時加鎖
    public synchronized void pass(String name,String address){
        this.counter++;
        this.name=name;
        this.address=address;
        verify();
    }
    //當條件不滿足時,進行toString打印。
    private  void verify(){
        if (this.name.charAt(0) != this.address.charAt(0)) {
            try {
                Thread.sleep(500);
                System.out.println("*******BROKEN********" + toString());
            }catch (Exception e){
            }
        }
    }

    @Override
    public String toString() {
        return "第"+counter + "個,名字:" + name  + "地址:" + address ;
    }
}

    public static void main(String [] args){
     Gate gate = new Gate();
     Userr sh = new Userr("ShangHai","Shang上海",gate);
     Userr bj = new Userr("eiJing","Bei北京",gate);
     Userr hf = new Userr("HeFei","e合肥",gate);

     hf.start();
     sh.start();
     bj.start();
    }