TaskManagerService.java

package org.menacheri.jetserver.service;

import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

import org.menacheri.jetserver.app.Task;


/**
 * Defines and interface for management of tasks in the server. It declares
 * functionality for executing recurring tasks with delay etc. The interface may
 * also be used as a repository of tasks, with features like persistence built
 * in by the implementation.
 * 
 * @author Abraham Menacherry
 * 
 */
public interface TaskManagerService
{
	public void execute(Task task);

	/**
	 * Creates and executes a one-shot action that becomes enabled after the given delay.
	 * @param task The task to be scheduled.
	 * @param delay Initial delay before the task is executed
	 * @param unit seconds, milliseconds etc for delay
	 * @return A scheduled future, which is a handle to the task and can be used
	 *         to cancel it, get completed status etc.
	 */
	@SuppressWarnings("rawtypes")
	public ScheduledFuture schedule(Task task, long delay, TimeUnit unit);

	/**
	 * Creates and executes a periodic action that becomes enabled first after
	 * the given initial delay, and subsequently with the given period; that is
	 * executions will commence after initialDelay then initialDelay+period,
	 * then initialDelay + 2 * period, and so on.
	 * 
	 * @param task
	 *            The task to be scheduled.
	 * @param initialDelay
	 *            Initial delay before the task is first done.
	 * @param period
	 *            Fixed period of execution.
	 * @param unit
	 *            seconds, milliseconds etc for delay.
	 * @return A scheduled future, which is a handle to the task and can be used
	 *         to cancel it, get completed status etc.
	 */
	@SuppressWarnings("rawtypes")
	public ScheduledFuture scheduleAtFixedRate(Task task, long initialDelay,
			long period, TimeUnit unit);

	/**
	 * Creates and executes a periodic action that becomes enabled first after
	 * the given initial delay, and subsequently with the given delay between
	 * the termination of one execution and the commencement of the next.
	 * 
	 * @param task
	 *            The task to be scheduled.
	 * @param initialDelay
	 *            Initial delay before the task is first done.
	 * @param delay
	 *            The delay between each subsequent execution
	 * @param unit
	 *            seconds, milliseconds etc for delay.
	 * @return A scheduled future, which is a handle to the task and can be used
	 *         to cancel it, get completed status etc.
	 */
	@SuppressWarnings("rawtypes")
	public ScheduledFuture scheduleWithFixedDelay(Task task,
			long initialDelay, long delay, TimeUnit unit);

}