content: /*
   * Copyright 2015 Adam Bien.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.airhacks.porcupine.execution.control;
  
  import static java.lang.Math.min;
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.RejectedExecutionHandler;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  /**
   *
   * @author airhacks.com
   */
  public class InstrumentedThreadPoolExecutor extends ThreadPoolExecutor {
  
      private int minRemainingQueueCapacity;
  
      public InstrumentedThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) {
          super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler);
          this.minRemainingQueueCapacity = workQueue.remainingCapacity();
      }
  
      @Override
      protected void afterExecute(Runnable r, Throwable t) {
          super.afterExecute(r, t);
      }
  
      @Override
      protected void beforeExecute(Thread t, Runnable r) {
          super.beforeExecute(t, r);
          int current = super.getQueue().remainingCapacity();
          this.minRemainingQueueCapacity = min(this.minRemainingQueueCapacity, current);
      }
  
      public int getMinRemainingQueueCapacity() {
          return minRemainingQueueCapacity;
      }
  }
  