Question

I have class A in which i have two methods defined ValidateA and ValidateB

class A {
   ValidateA() {
        /////
    }

   ValidateB() {
        ////
    }
}

I want to run both these steps in parallel at same time and get there combined status. How can i proceed using threads?

Answer 1

It is always recommended to make use of the great Executors classes introduced in Java 5. They help you manage your background tasks and hides the Thread code from your classes.

Something like the following would work. It creates a thread-pool, submits 2 Runnable classes which each call one of the validate methods, and then waits for them to finish and return. It uses a Result object that you will have to make up. It could also be a String or Integer and depends on what the validate methods return.

// reate an open-ended thread pool
ExecutorService threadPool = Executors.newCachedThreadPool();
// since you want results from the validate methods, we need a list of Futures
Future<Result> futures = new ArrayList<Result>();
futures.add(threadPool.submit(new Callable<Result>() {
    public Result call() {
       return a.ValidateA();
    } 
});
futures.add(threadPool.submit(new Callable<Result>() {
    public Result call() {
       return a.ValidateB();
    } 
});
// once we have submitted all jobs to the thread pool, it should be shutdown,
// the already submitted jobs will continue to run
threadPool.shutdown();

// we wait for the jobs to finish so we can get the results
for (Future future : futures) {
    // this can throw an ExecutionException if the validate methods threw
    Result result = future.get();
    // ...
}