common/util/src/main/java/org/opendaylight/yangtools/util/concurrent/CountingRejectedExecutionHandler.java

   1 /*
   2  * Copyright (c) 2014 Brocade Communications Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.yangtools.util.concurrent;
  10
  11 import static java.util.Objects.requireNonNull;
  12
  13 import java.util.concurrent.RejectedExecutionHandler;
  14 import java.util.concurrent.ThreadPoolExecutor;
  15 import java.util.concurrent.atomic.LongAdder;
  16 import org.opendaylight.yangtools.util.ExecutorServiceUtil;
  17
  18 /**
  19  * A RejectedExecutionHandler that delegates to a backing RejectedExecutionHandler and counts the
  20  * number of rejected tasks.
  21  *
  22  * @author Thomas Pantelis
  23  */
  24 public class CountingRejectedExecutionHandler implements RejectedExecutionHandler {
  25     private final LongAdder rejectedTaskCounter = new LongAdder();
  26     private final RejectedExecutionHandler delegate;
  27
  28     /**
  29      * Constructor.
  30      *
  31      * @param delegate the backing RejectedExecutionHandler.
  32      */
  33     public CountingRejectedExecutionHandler(final RejectedExecutionHandler delegate) {
  34         this.delegate = requireNonNull(delegate);
  35     }
  36
  37     @Override
  38     public void rejectedExecution(final Runnable task, final ThreadPoolExecutor executor) {
  39         rejectedTaskCounter.increment();
  40         delegate.rejectedExecution(task, executor);
  41     }
  42
  43     /**
  44      * Returns the rejected task count.
  45      */
  46     public long getRejectedTaskCount() {
  47         return rejectedTaskCounter.sum();
  48     }
  49
  50     /**
  51      * Returns a counting handler for rejected tasks that runs the rejected task directly in the
  52      * calling thread of the execute method, unless the executor has been shut down, in which case
  53      * the task is discarded.
  54      */
  55     public static CountingRejectedExecutionHandler newCallerRunsPolicy() {
  56         return new CountingRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
  57     }
  58
  59     /**
  60      * Returns a counting handler for rejected tasks that throws a RejectedExecutionException.
  61      */
  62     public static CountingRejectedExecutionHandler newAbortPolicy() {
  63         return new CountingRejectedExecutionHandler(new ThreadPoolExecutor.AbortPolicy());
  64     }
  65
  66     /**
  67      * Returns a counting handler for rejected tasks that blocks on the
  68      * {@link ThreadPoolExecutor}'s backing queue until it can add the task to the queue.
  69      */
  70     public static CountingRejectedExecutionHandler newCallerWaitsPolicy() {
  71         return new CountingRejectedExecutionHandler(ExecutorServiceUtil.waitInQueueExecutionHandler());
  72     }
  73 }