Java Tutorial : CountDownLatch

CountDownLatch are used to control to flow of multiple running task. CDL delays the run time of tasks before the main thread is ran. Its simply a timer that counts down to zero and when timer hits zero the main thread is ran but during its count down it is also running other tasks .

import java.util.concurrent.CountDownLatch; 

public class countdown 
{ 
    public static void main(String args[])  
                   throws InterruptedException 
    { 

//       Creating CountDownLatch , there are 3 task being executed 
        CountDownLatch cdl = new CountDownLatch(3); 
  
//       Naming tasks and setting delay times 
//        1 second delay
        Task Task_One = new Task(1000, cdl,  "task 1"); 
//        5 second delay
        Task Task_Two = new Task(5000, cdl,  "task 2"); 
//        3 second delay 
        Task Task_Three = new Task(3000, cdl,   "task 3"); 

//       Starting tasks
        Task_One.start(); 
        Task_Two.start(); 
        Task_Three.start(); 
      
  
        // The main task waits here
        cdl.await(); 
  
        // Main thread running 
        System.out.println(Thread.currentThread().getName() + 
                           " You have hacked the main frame!"); 
        
    } 
} 
  
// What main thread does while waiting  
class Task extends Thread 
{ 
    private int dt; 
    private CountDownLatch cdl; 
  
    public Task(int dt, CountDownLatch cdl, 
                                    String name) 
    { 
        super(name); 
        this.dt = dt; 
        this.cdl = cdl; 
    } 
  
    @Override
    public void run() 
    { 
        try
        { 
//           task ran complete print finished 
            Thread.sleep(dt); 
            cdl.countDown(); 
            System.out.println(Thread.currentThread().getName() 
                            + " finished"); 
        } 
//        if not throw exception 
        catch (InterruptedException e) 
        { 
            e.printStackTrace(); 
        } 
    } 
} 
Output :
task 1 finished
task 3 finished
task 2 finished
main You have hacked the main frame!

Android Studio Loading Animation Between Activities

Progress Dialog is dialog showing a progress indicator and an optional text message or view. The methods of Progress Dialog being used in this tutorial are: ProgressDialog.setTitle() – Used to set title of dialog box ProgressDialog.setMessage() – Used to set dialog message being displayed ProgressDialog.setProgressStyle() – Choose the style of indicator ProgressDialog.dismiss() – Dismiss the … Read more Android Studio Loading Animation Between Activities

Android Studio Tutorial SeekBar

SeekBar is an extension of ProgressBar that adds a draggable thumb. The user can touch thumb and drag left or right to set the current progress level or various other task. In this example, the seekbar will be used to display a percentage. As the user moves the SeekBar left to right the percentage value … Read more Android Studio Tutorial SeekBar

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