Multi-threaded design patterns CountDown

Scene: the control logic steps performed

Doug Lea's implementation CountDownLatch

Package com.dwz.concurrency2.chapter15; 

Import java.util.Random;
 Import java.util.concurrent.CountDownLatch;
 Import java.util.stream.IntStream; 

public  class JDKCountDown {
     Private  Final  static the Random Random = new new the Random (System.currentTimeMillis ()); 
    
    public  static  void main (String [] args) throws InterruptedException {
         Final CountDownLatch LATCH = new new CountDownLatch (5 ); 
        
        System.out.println ( "ready multi-threaded processing tasks ..." );
         // Step
        IntStream.rangeClosed (. 1,. 5) .forEach (I -> {
             new new the Thread (() -> { 
                System.out.println (Thread.currentThread () getName (). + "Working IS." );
                 The try { 
                    the Thread. SLEEP (random.nextInt ( 1000 )); 
                } the catch (InterruptedException E) { 
                    e.printStackTrace (); 
                } 
                // marking end 
                latch.countDown (); 
            }, String.valueOf (I)) Start ();. 
        }) ; 
        
        // wait for all tasks end 
        latch.await ();
         //Step 
        System.out.println ( "multi-threaded task all over, preparing for the second phase of the task" ); 
        System.out.println ( "................... " ); 
        System.out.println ( " FINISH " ); 
    } 
}

A custom CountDown

package com.dwz.concurrency2.chapter15;

public class CountDown {
    private final int total;
    private int counter = 0;
    
    public CountDown(int total) {
        this.total = total;
    }
    
    public void down() {
        synchronized (this) {
            this.counter++;
            this.notifyAll();
        }
    }
    
    public void await() throws InterruptedException {
        synchronized (this) {
            while (counter != total) {
                this.wait();
            }
        }
    }
}

Custom CountDown test

Package com.dwz.concurrency2.chapter15; 

Import java.util.Random;
 Import java.util.concurrent.CountDownLatch;
 Import java.util.stream.IntStream; 

public  class CustomCountDown {
     Private  Final  static the Random Random = new new the Random (System.currentTimeMillis ()); 
    
    public  static  void main (String [] args) throws InterruptedException {
         Final CountDown LATCH = new new CountDown (5 ); 
        System.out.println ( "ready multi-threaded processing tasks ..." );
         // Step
        IntStream.rangeClosed (. 1,. 5) .forEach (I -> {
             new new the Thread (() -> { 
                System.out.println (Thread.currentThread () getName (). + "Working IS." );
                 The try { 
                    the Thread. SLEEP (random.nextInt ( 1000 )); 
                } the catch (InterruptedException E) { 
                    e.printStackTrace (); 
                } 
                // marking end 
                latch.down (); 
            }, String.valueOf (I)) Start ();. 
        }) ; 
        
        // wait for all tasks end 
        latch.await ();
         // Step
        System.out.println ( "multi-threaded task all over, preparing for the second phase of the task" ); 
        System.out.println ( "..................." ); 
        System.out.println ( "FINISH" ); 
    } 


}

Test Results:

Ready multi-threaded processing tasks. . .
Working IS 2.
4 IS Working.
1 IS Working.
3 IS Working.
5 IS Working.
Multithreaded all over, preparing for the second phase of the task
...................
FINISH