/*
    * 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.addthis.codec.utils;
  
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  import com.addthis.codec.annotations.Time;
  
  import com.google.common.annotations.Beta;
  import com.google.common.util.concurrent.MoreExecutors;
  
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonProperty;
  import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
  import com.yammer.metrics.Metrics;
  
  @Beta
  @JsonDeserialize(builder = ExecutorServiceBuilder.class)
  public class ExecutorServiceBuilder {
  
      private final ThreadFactory threadFactory;
      private final int coreThreads;
      private final int maxThreads;
      private final int keepAlive;
      private final BlockingQueue<Runnable> queue;
      private final boolean shutdownHook;
  
      @JsonCreator
      public ExecutorServiceBuilder(@JsonProperty("thread-factory") ThreadFactory threadFactory,
                                    @JsonProperty("core-threads") int coreThreads,
                                    @JsonProperty("max-threads") int maxThreads,
                                    @JsonProperty("keep-alive") @Time(TimeUnit.MILLISECONDS) int keepAlive,
                                    @JsonProperty("queue-size") int queueSize,
                                    @JsonProperty("queue-gauge-class") Class<?> gaugeClass,
                                    @JsonProperty("queue-gauge-name") String gaugeName,
                                    @JsonProperty("shutdown-hook") boolean shutdownHook) {
          this.threadFactory = threadFactory;
          this.coreThreads = coreThreads;
          this.maxThreads = maxThreads;
          this.keepAlive = keepAlive;
          this.queue = new LinkedBlockingQueue<>(queueSize);
          if ((gaugeClass != null) && (gaugeName != null)) {
              Metrics.newGauge(gaugeClass, gaugeName, new SizeGauge(queue));
          }
          this.shutdownHook = shutdownHook;
      }
  
      public ExecutorService build() {
          ThreadPoolExecutor service = new ThreadPoolExecutor(coreThreads, maxThreads,
                                                              keepAlive, TimeUnit.MILLISECONDS,
                                                              queue, threadFactory);
          if (shutdownHook) {
              return MoreExecutors.getExitingExecutorService(service);
          } else {
              return service;
          }
      }
  }