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 com.google.common.base.Preconditions;
  12 import java.util.concurrent.RejectedExecutionHandler;
  13 import java.util.concurrent.ThreadPoolExecutor;
  14 import java.util.concurrent.atomic.LongAdder;
  15 import org.opendaylight.yangtools.util.ExecutorServiceUtil;
  16
  17 /**
  18  * A RejectedExecutionHandler that delegates to a backing RejectedExecutionHandler and counts the
  19  * number of rejected tasks.
  20  *
  21  * @author Thomas Pantelis
  22  */
  23 public class CountingRejectedExecutionHandler implements RejectedExecutionHandler {
  24     private final LongAdder rejectedTaskCounter = new LongAdder();
  25     private final RejectedExecutionHandler delegate;
  26
  27     /**
  28      * Constructor.
  29      *
  30      * @param delegate the backing RejectedExecutionHandler.
  31      */
  32     public CountingRejectedExecutionHandler( final RejectedExecutionHandler delegate ) {
  33         this.delegate = Preconditions.checkNotNull( delegate );
  34     }
  35
  36     @Override
  37     public void rejectedExecution( final Runnable task, final ThreadPoolExecutor executor ) {
  38         rejectedTaskCounter.increment();
  39         delegate.rejectedExecution(task, executor);
  40     }
  41
  42     /**
  43      * Returns the rejected task count.
  44      */
  45     public long getRejectedTaskCount() {
  46         return rejectedTaskCounter.sum();
  47     }
  48
  49     /**
  50      * Returns s counting handler for rejected tasks that runs the rejected task directly in the
  51      * calling thread of the execute method, unless the executor has been shut down, in which case
  52      * the task is discarded.
  53      */
  54     public static CountingRejectedExecutionHandler newCallerRunsPolicy() {
  55         return new CountingRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
  56     }
  57
  58     /**
  59      * Returns a counting handler for rejected tasks that throws a RejectedExecutionException.
  60      */
  61     public static CountingRejectedExecutionHandler newAbortPolicy() {
  62         return new CountingRejectedExecutionHandler(new ThreadPoolExecutor.AbortPolicy());
  63     }
  64
  65     /**
  66      * Returns a counting handler for rejected tasks that that blocks on the
  67      * {@link ThreadPoolExecutor}'s backing queue until it can add the task to the queue.
  68      */
  69     public static CountingRejectedExecutionHandler newCallerWaitsPolicy() {
  70         return new CountingRejectedExecutionHandler(ExecutorServiceUtil.waitInQueueExecutionHandler());
  71     }
  72 }