java.util.concurrent
Interface Executor

All Known Subinterfaces:

ExecutorService, ScheduledExecutorService

All Known Implementing Classes:

AbstractExecutorService, ScheduledThreadPoolExecutor, ThreadPoolExecutor

public interface Executor

An object that executes submitted Runnable tasks. This interface provides a way of decoupling task submission from the mechanics of how each task will be run, including details of thread use, scheduling, etc. An Executor is normally used instead of explicitly creating threads. For example, rather than invoking new Thread(new(RunnableTask())).start() for each of a set of tasks, you might use:

 Executor executor = anExecutor;
 executor.execute(new RunnableTask1());
 executor.execute(new RunnableTask2());
 ...
 

 class DirectExecutor implements Executor {
     public void execute(Runnable r) {
         r.run();
     }
 }

 class ThreadPerTaskExecutor implements Executor {
     public void execute(Runnable r) {
         new Thread(r).start();
     }
 }

 class SerialExecutor implements Executor {
     final Queue<Runnable> tasks = new ArrayDeque<Runnable>();
     final Executor executor;
     Runnable active;

     SerialExecutor(Executor executor) {
         this.executor = executor;
     }

     public synchronized void execute(final Runnable r) {
         tasks.offer(new Runnable() {
             public void run() {
                 try {
                     r.run();
                 } finally {
                     scheduleNext();
                 }
             }
         });
         if (active == null) {
             scheduleNext();
         }
     }

     protected synchronized void scheduleNext() {
         if ((active = tasks.poll()) != null) {
             executor.execute(active);
         }
     }
 }

Memory consistency effects: Actions in a thread prior to submitting a Runnable object to an Executor happen-before its execution begins, perhaps in another thread.

Since:

1.5

Method Summary
void	execute(Runnable command)           Executes the given command at some time in the future.

 

Method Detail

execute

void execute(Runnable command)

Executes the given command at some time in the future. The command may execute in a new thread, in a pooled thread, or in the calling thread, at the discretion of the Executor implementation.

Parameters:

command - the runnable task

Throws:

RejectedExecutionException - if this task cannot be accepted for execution.

NullPointerException - if command is null