Tips n tricks for Threads

  • Multithreading means multiple lines of a single program can be executed at the same time. The operating system is treating the programs as two separate and distinct processes. 
  • Two ways of creating threads are : implementing an interface and extending a class. 
  • The run() method is where all the work of theCounter class thread is done. 
  • Only classes that implement the Runnable interface (and so are of type Runnable) can be targets of threads.
  • The call to start() will call the target's run() method. The call to start() will return right away and the thread will start executing at the same time.
  • Once a thread is stopped, it cannot be restarted with the start()command, since stop() will terminate the execution of a thread. Instead you can pause the execution of a thread with the sleep()method or temporarily cease the execution using suspend() method and resume() it at later point.
  • Scheduling threads example. 
  • Which exception might wait() throw? "InterruptedException" or "IllegalMonitorException". 
  • Read about thread in detail here.
  • Typical Producer Consumer example:
class Shared {
int num=0;
boolean value = false;
synchronized int get() {
  if (value==false)
  try {
    wait();
    }
  catch (InterruptedException e) {
     System.out.println("InterruptedException caught");
  }
System.out.println("consume: " + num);
value=false;
notify();
return num;
}
synchronized void put(int num) {
if (value==true)
  try {
    wait();
  }
  catch (InterruptedException e) {
      System.out.println("InterruptedException caught");
  }
    this.num=num;
    System.out.println("Produce: " + num);
    value=false;
    notify();
    }
    }

class Producer extends Thread {
  Shared s;
  Producer(Shared s) {
    this.s=s;
    this.start();
  }
  public void run() {
    int i=0;
    s.put(++i);
    }
}

class Consumer extends Thread{
  Shared s;
  Consumer(Shared s) {
    this.s=s;
    this.start();
  }
  public void run() {
    s.get();
    }}
public class InterThread{
  public static void main(String[] args) 
  {
    Shared s=new Shared();
    new Producer(s);
    new Consumer(s);
  }
}

Comments

Post a Comment

Popular posts from this blog

jQgrid reload with new data

To reload a jQGrid with fresh data you need to set the data parameter on the grid and invoke reload on it. jQuery("#promotionsGrid").setGridParam({ 'data': newData}).trigger("reloadGrid"); Here newData is a JavaScript array with which I need to re-load the grid. The important thing here is that I had to place this statement just before the grid initialization code even though the reload was expected on change event of a text box. Without that there was simply no effect on my grid!
Read more

Introduction to jQgrid

Introduction Why waste time in developing lists /customizing Liferay OOB search container to display data in tabular format. On top of that more often then not we end up coding for sorting of columns, pagination and formatting some data depending on their values. Trirand has come up with a jQuery plugin called jQgrid. jQgrid supports all of such ease. It provides a nice-looking grid with built-in features such as sorting, editing, search, drill-down, tree lists, and more. It is based upon jQuery and integrates well with Liferay.  The grid is dual-licensed under both the GPL and MIT licenses  (just like
Read more

Rich Client based UI technologies- A Comparison of Thick Client UI tools

Rich Client v/s Thin Client Software developers face many difficult decisions when building new applications, not the least of which is graphical user interface. There are various graphical user interface technologies used, but broadly they can be classified as Rich Client User interfaces and the thin client or web based user interfaces. To understand them better let us look at the history of rich and thin clients. While the Rich client GUI applications would support high quality end-user experience with features such a drag-and-drop, perspectives, customization, high speed local processing; it has had a traditional disadvantage of high deployment and upgrade costs. It was becoming highly difficult and costly to deploy and upgrade these applications. Then came the thin clients or the Web based applications. Thin clients solved many of the deployment and upgrade problems, but that was not without a cost, the cost was in terms of functionality and capability. Thin clients, based on...
Read more