software.nealk.concurrent.tasks.RetrievableTask Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of nealk-sdk-concurrent-lib Show documentation

An easy-to-consume concurrency library allowing for "Tasks" to execute business logic in a thread safe manner. This library helps users achieve multi-threading in their applications without worrying about synchronization and blocking for race conditions.

The newest version!

package software.nealk.concurrent.tasks;

import software.nealk.concurrent.Task;
import software.nealk.concurrent.ThreadSafe;

public abstract class RetrievableTask implements Task{
	
	protected volatile T obj;
	private java.util.concurrent.Semaphore objSem;
	
	protected RetrievableTask(){
		this.objSem = new java.util.concurrent.Semaphore(0, false);
	}

	@Override
	public final void run() {
		System.out.println("Thread " 
							+ Thread.currentThread().getId()
							+ " is running....");
		this.execute();
		this.objSem.release();
	}
	
	protected abstract void execute();

	/**
	 * Blocks until {@link obj} of type <T> is not null. Returns the {@link obj}.
	 * 


	 * Note that compile-time type checking is enabled. The usage 
	 * of Java Generics nullifies the compiler warning "unchecked".
	 */
	@SuppressWarnings("unchecked") 
	@Override 
	@ThreadSafe
	public final T getVal() throws InterruptedException {
		this.objSem.acquire();
		return obj;
	}

}