/**
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.hadoop.hbase.thrift;
  
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  /**
   * A ThreadPoolExecutor customized for working with HBase thrift to update metrics before and
   * after the execution of a task.
   */
  
  public class THBaseThreadPoolExecutor extends ThreadPoolExecutor {
  
    private ThriftMetrics metrics;
  
    public THBaseThreadPoolExecutor(int corePoolSize, int maxPoolSize, long keepAliveTime,
        TimeUnit unit, BlockingQueue<Runnable> workQueue, ThriftMetrics metrics) {
      this(corePoolSize, maxPoolSize, keepAliveTime, unit, workQueue, null, metrics);
    }
  
    public THBaseThreadPoolExecutor(int corePoolSize, int maxPoolSize, long keepAliveTime,
        TimeUnit unit, BlockingQueue<Runnable> workQueue,
        ThreadFactory threadFactory,ThriftMetrics metrics) {
      super(corePoolSize, maxPoolSize, keepAliveTime, unit, workQueue);
      if (threadFactory != null) {
        setThreadFactory(threadFactory);
      }
      this.metrics = metrics;
    }
  
    @Override
    protected void beforeExecute(Thread t, Runnable r) {
      super.beforeExecute(t, r);
      metrics.incActiveWorkerCount();
    }
  
    @Override
    protected void afterExecute(Runnable r, Throwable t) {
      metrics.decActiveWorkerCount();
      super.afterExecute(r, t);
    }
  }