Beispiel #1
0
  /**
   * Execute the {@link Callable} tasks in parallel (per the configured size of the {@link
   * WorkerPool}) and wait for them to complete.
   *
   * @param tasks a map of {@link Callable}s with keys by which you will be able to access each
   *     return value
   * @return the return values of each {@link Callable}s mapped by their input key
   */
  public <K, V> Map<K, V> invokeAll(Map<K, Callable<V>> tasks) {
    String caller =
        LOGGER.isDebugEnabled() ? Thread.currentThread().getStackTrace()[2].toString() : "n/a";
    LOGGER.debug("[%s] is invoking %d mapped tasks", caller, tasks.size());

    List<K> orderedKeys = new ArrayList<K>(tasks.size());
    List<Callable<V>> orderedTasks = new ArrayList<Callable<V>>(tasks.size());
    for (Map.Entry<K, Callable<V>> entry : tasks.entrySet()) {
      orderedKeys.add(entry.getKey());
      orderedTasks.add(entry.getValue());
    }

    try {
      long start = System.currentTimeMillis();
      List<Future<V>> executorResults = executorService.invokeAll(orderedTasks);
      long finish = System.currentTimeMillis();
      LOGGER.debug("[%s] invoked %d mapped tasks in %d ms", caller, tasks.size(), finish - start);

      Map<K, V> mappedResults = new LinkedHashMap<K, V>(tasks.size());
      for (int i = 0; i < tasks.size(); i++) {
        K key = orderedKeys.get(i);
        V result = executorResults.get(i).get();
        mappedResults.put(key, result);
      }
      return mappedResults;
    } catch (InterruptedException e) {
      throw new RuntimeException(e);
    } catch (ExecutionException e) {
      throw new RuntimeException(e);
    }
  }
Beispiel #2
0
  /**
   * Create a pool with the specified number of threads.
   *
   * @param nThreads
   */
  public WorkerPool(int nThreads) {
    LOGGER.debug("initializing worker pool with %d threads", nThreads);

    executorService =
        LOGGER.isDebugEnabled()
            ? new MetricReportingExecutorService(LOGGER, nThreads)
            : Executors.newFixedThreadPool(nThreads);

    Runtime.getRuntime()
        .addShutdownHook(
            new Thread() {
              @Override
              public void run() {
                shutdownAndAwaitTermination(10);
              }
            });
  }
Beispiel #3
0
 public static void main(String[] args) {
   WorkerPool workerPool = new WorkerPool(3);
   mapExample(workerPool);
   listExample(workerPool);
   slowExample(workerPool, 5);
   if (LOGGER.isDebugEnabled()) {
     ((MetricReportingExecutorService) workerPool.executorService).tick();
     ((MetricReportingExecutorService) workerPool.executorService).report();
   }
   System.exit(0);
 }
Beispiel #4
0
  /**
   * Execute the {@link Callable} tasks in parallel (per the configured size of the {@link
   * WorkerPool}) and wait for them to complete.
   *
   * @param tasks a list of {@link Callable}s
   * @return the ordered return values
   */
  public <T> List<T> invokeAll(List<Callable<T>> tasks) {
    String caller =
        LOGGER.isDebugEnabled() ? Thread.currentThread().getStackTrace()[2].toString() : "n/a";
    LOGGER.debug("[%s] is invoking %d listed tasks", caller, tasks.size());

    try {
      long start = System.currentTimeMillis();
      List<Future<T>> executorResults = executorService.invokeAll(tasks);
      long finish = System.currentTimeMillis();
      LOGGER.debug("[%s] invoked %d listed tasks in %d ms", caller, tasks.size(), finish - start);

      List<T> results = new ArrayList<T>(tasks.size());
      for (Future<T> future : executorResults) {
        results.add(future.get());
      }
      return results;
    } catch (InterruptedException e) {
      throw new RuntimeException(e);
    } catch (ExecutionException e) {
      throw new RuntimeException(e);
    }
  }