Package com.microstrategy.webapi.utils

Class ExecutorServiceCloseable

  • All Implemented Interfaces:
    java.lang.AutoCloseable, java.util.concurrent.Executor, java.util.concurrent.ExecutorService
    public class ExecutorServiceCloseable
extends java.lang.Object
implements java.util.concurrent.ExecutorService, java.lang.AutoCloseable
    An Executor ExecutorServiceCloseable that is also AutoCloseable, meaning you can use it in a try with resources statement.

    An Executor that provides methods to manage termination and methods that can produce a Future for tracking progress of one or more asynchronous tasks.

    An ExecutorService can be shut down, which will cause it to reject new tasks. Two different methods are provided for shutting down an ExecutorService. The shutdown() method will allow previously submitted tasks to execute before terminating, while the shutdownNow() method prevents waiting tasks from starting and attempts to stop currently executing tasks. Upon termination, an executor has no tasks actively executing, no tasks awaiting execution, and no new tasks can be submitted. An unused ExecutorService should be shut down to allow reclamation of its resources.

    Method submit extends base method Executor.execute(java.lang.Runnable) by creating and returning a Future that can be used to cancel execution and/or wait for completion. Methods invokeAny and invokeAll perform the most commonly useful forms of bulk execution, executing a collection of tasks and then waiting for at least one, or all, to complete. (Class ExecutorCompletionService can be used to write customized variants of these methods.)

    The Executors class provides factory methods for the executor services provided in this package.

    Usage Examples

    Here is a sketch of a network service in which threads in a thread pool service incoming requests. It uses the preconfigured Executors.newFixedThreadPool(int) factory method: 
     class NetworkService implements Runnable {
   private final ServerSocket serverSocket;
   private final ExecutorService pool;

   public NetworkService(int port, int poolSize)
       throws IOException {
     serverSocket = new ServerSocket(port);
     pool = Executors.newFixedThreadPool(poolSize);
   }

   public void run() { // run the service
     try {
       for (;;) {
         pool.execute(new Handler(serverSocket.accept()));
       }
     } catch (IOException ex) {
       pool.shutdown();
     }
   }
 }

 class Handler implements Runnable {
   private final Socket socket;
   Handler(Socket socket) { this.socket = socket; }
   public void run() {
     // read and service request on socket
   }
 }
    The following method shuts down an ExecutorService in two phases, first by calling shutdown to reject incoming tasks, and then calling shutdownNow, if necessary, to cancel any lingering tasks: 
     void shutdownAndAwaitTermination(ExecutorService pool) {
   pool.shutdown(); // Disable new tasks from being submitted
   try {
     // Wait a while for existing tasks to terminate
     if (!pool.awaitTermination(60, TimeUnit.SECONDS)) {
       pool.shutdownNow(); // Cancel currently executing tasks
       // Wait a while for tasks to respond to being cancelled
       if (!pool.awaitTermination(60, TimeUnit.SECONDS))
           System.err.println("Pool did not terminate");
     }
   } catch (InterruptedException ie) {
     // (Re-)Cancel if current thread also interrupted
     pool.shutdownNow();
     // Preserve interrupt status
     Thread.currentThread().interrupt();
   }
 }

    Memory consistency effects: Actions in a thread prior to the submission of a Runnable or Callable task to an ExecutorService happen-before any actions taken by that task, which in turn happen-before the result is retrieved via Future.get().

    Since:
    1.5

    • Constructor Summary

      Constructors 
      Constructor Description
      ExecutorServiceCloseable​(int iThreadCount, java.lang.String iThreadPoolName)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean awaitTermination​(long timeout, java.util.concurrent.TimeUnit unit)  
      void close()  
      void execute​(java.lang.Runnable command)  
      <T> java.util.List<java.util.concurrent.Future<T>> invokeAll​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks)  
      <T> java.util.List<java.util.concurrent.Future<T>> invokeAll​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks, long timeout, java.util.concurrent.TimeUnit unit)  
      <T> T invokeAny​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks)  
      <T> T invokeAny​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks, long timeout, java.util.concurrent.TimeUnit unit)  
      boolean isShutdown()  
      boolean isTerminated()  
      void shutdown()  
      java.util.List<java.lang.Runnable> shutdownNow()  
      java.util.concurrent.Future<?> submit​(java.lang.Runnable task)  
      <T> java.util.concurrent.Future<T> submit​(java.lang.Runnable task, T result)  
      <T> java.util.concurrent.Future<T> submit​(java.util.concurrent.Callable<T> task)  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • ExecutorServiceCloseable

        public ExecutorServiceCloseable​(int iThreadCount,
                                java.lang.String iThreadPoolName)

    • Method Detail

      • execute

        public void execute​(java.lang.Runnable command)
        Specified by:
        execute in interface java.util.concurrent.Executor

      • shutdown

        public void shutdown()
        Specified by:
        shutdown in interface java.util.concurrent.ExecutorService

      • shutdownNow

        public java.util.List<java.lang.Runnable> shutdownNow()
        Specified by:
        shutdownNow in interface java.util.concurrent.ExecutorService

      • isShutdown

        public boolean isShutdown()
        Specified by:
        isShutdown in interface java.util.concurrent.ExecutorService

      • isTerminated

        public boolean isTerminated()
        Specified by:
        isTerminated in interface java.util.concurrent.ExecutorService

      • awaitTermination

        public boolean awaitTermination​(long timeout,
                                java.util.concurrent.TimeUnit unit)
                         throws java.lang.InterruptedException
        Specified by:
        awaitTermination in interface java.util.concurrent.ExecutorService
        Throws:
        java.lang.InterruptedException

      • submit

        public <T> java.util.concurrent.Future<T> submit​(java.util.concurrent.Callable<T> task)
        Specified by:
        submit in interface java.util.concurrent.ExecutorService

      • submit

        public <T> java.util.concurrent.Future<T> submit​(java.lang.Runnable task,
                                                 T result)
        Specified by:
        submit in interface java.util.concurrent.ExecutorService

      • submit

        public java.util.concurrent.Future<?> submit​(java.lang.Runnable task)
        Specified by:
        submit in interface java.util.concurrent.ExecutorService

      • invokeAll

        public <T> java.util.List<java.util.concurrent.Future<T>> invokeAll​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks)
                                                             throws java.lang.InterruptedException
        Specified by:
        invokeAll in interface java.util.concurrent.ExecutorService
        Throws:
        java.lang.InterruptedException

      • invokeAll

        public <T> java.util.List<java.util.concurrent.Future<T>> invokeAll​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks,
                                                                    long timeout,
                                                                    java.util.concurrent.TimeUnit unit)
                                                             throws java.lang.InterruptedException
        Specified by:
        invokeAll in interface java.util.concurrent.ExecutorService
        Throws:
        java.lang.InterruptedException

      • invokeAny

        public <T> T invokeAny​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks)
                throws java.lang.InterruptedException,
                       java.util.concurrent.ExecutionException
        Specified by:
        invokeAny in interface java.util.concurrent.ExecutorService
        Throws:
        java.lang.InterruptedException
        java.util.concurrent.ExecutionException

      • invokeAny

        public <T> T invokeAny​(java.util.Collection<? extends java.util.concurrent.Callable<T>> tasks,
                       long timeout,
                       java.util.concurrent.TimeUnit unit)
                throws java.lang.InterruptedException,
                       java.util.concurrent.ExecutionException,
                       java.util.concurrent.TimeoutException
        Specified by:
        invokeAny in interface java.util.concurrent.ExecutorService
        Throws:
        java.lang.InterruptedException
        java.util.concurrent.ExecutionException
        java.util.concurrent.TimeoutException

      • close

        public void close()
        Specified by:
        close in interface java.lang.AutoCloseable