content: /*
   * 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.ambari.server.controller.test;
  
  import java.util.concurrent.Future;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.ambari.server.controller.utilities.BufferedThreadPoolExecutorCompletionService;
  import org.apache.ambari.server.controller.utilities.ScalingThreadPoolExecutor;
  import org.junit.Test;
  
  import junit.framework.Assert;
  
  public class BufferedThreadPoolExecutorCompletionServiceTest {
  
    private void longOp() throws InterruptedException {
      Thread.sleep(700);
      System.out.println("Completed " + Thread.currentThread());
    }
  
    /**
     * Tests that when unbounded queue provided to executor, only
     * {@link ThreadPoolExecutor#getCorePoolSize()} threads are launched
     *
     * @throws InterruptedException
     */
    @Test
    public void testOnlyCorePoolThreadsLaunchedForUnboundedQueue() throws InterruptedException {
      int CORE_POOL_SIZE = 2;
      int MAX_POOL_SIZE = 5;
      int TASKS_COUNT = 8;
      LinkedBlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
      ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(CORE_POOL_SIZE, MAX_POOL_SIZE, 30000, TimeUnit.MILLISECONDS, queue);
      BufferedThreadPoolExecutorCompletionService<Runnable> service = new BufferedThreadPoolExecutorCompletionService<>(threadPoolExecutor);
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        service.submit(new Runnable() {
          @Override
          public void run() {
            try {
              longOp();
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
          }
        }, null);
      }
  
      // While waiting for tasks completion, check how many threads are being used
      Thread.sleep(500);
      Assert.assertEquals(CORE_POOL_SIZE, threadPoolExecutor.getActiveCount());
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        Future<Runnable> take = service.take();
        Assert.assertTrue(take.isDone());
        Assert.assertTrue("No more than CORE_POOL_SIZE threads should be launched", threadPoolExecutor.getActiveCount() <= CORE_POOL_SIZE);
      }
      threadPoolExecutor.shutdown();
    }
  
    /**
     * Tests that when load is more than core-pool-size and less than
     * max-pool-size, the number of threads scales up.
     *
     * @throws InterruptedException
     */
    @Test
    public void testLessThanMaxPoolSizeThreadsLaunched() throws InterruptedException {
      int CORE_POOL_SIZE = 2;
      int MAX_POOL_SIZE = 10;
      int TASKS_COUNT = 8;
      LinkedBlockingQueue<Runnable> queue = new LinkedBlockingQueue<>(CORE_POOL_SIZE);
      ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(CORE_POOL_SIZE, MAX_POOL_SIZE, 30000, TimeUnit.MILLISECONDS, queue);
      BufferedThreadPoolExecutorCompletionService<Runnable> service = new BufferedThreadPoolExecutorCompletionService<>(threadPoolExecutor);
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        service.submit(new Runnable() {
          @Override
          public void run() {
            try {
              longOp();
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
          }
        }, null);
      }
  
      // While waiting for tasks completion, check how many threads are being used
      Thread.sleep(500);
      Assert.assertEquals(TASKS_COUNT - CORE_POOL_SIZE, threadPoolExecutor.getActiveCount());
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        Future<Runnable> take = service.take();
        Assert.assertTrue(take.isDone());
        Assert.assertTrue("No more than TASKS_COUNT threads should be launched", threadPoolExecutor.getActiveCount() <= TASKS_COUNT);
      }
      threadPoolExecutor.shutdown();
    }
  
    /**
     * Tests that when load is more than max-pool-size, the number of threads
     * scales up.
     *
     * @throws InterruptedException
     */
    @Test
    public void testMaxPoolSizeThreadsLaunched() throws InterruptedException {
      int CORE_POOL_SIZE = 2;
      int MAX_POOL_SIZE = 10;
      int TASKS_COUNT = 24;
      LinkedBlockingQueue<Runnable> queue = new LinkedBlockingQueue<>(CORE_POOL_SIZE);
      ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(CORE_POOL_SIZE, MAX_POOL_SIZE, 30000, TimeUnit.MILLISECONDS, queue);
      BufferedThreadPoolExecutorCompletionService<Runnable> service = new BufferedThreadPoolExecutorCompletionService<>(threadPoolExecutor);
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        service.submit(new Runnable() {
          @Override
          public void run() {
            try {
              longOp();
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
          }
        }, null);
      }
  
      // While waiting for tasks completion, check how many threads are being used
      Thread.sleep(500);
      Assert.assertEquals(MAX_POOL_SIZE, threadPoolExecutor.getActiveCount());
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        Future<Runnable> take = service.take();
        Assert.assertTrue(take.isDone());
        Assert.assertTrue("No more than MAX_POOL_SIZE threads should be launched", threadPoolExecutor.getActiveCount() <= MAX_POOL_SIZE);
      }
      threadPoolExecutor.shutdown();
    }
  
    /**
     * Tests that when load is more than max-pool-size, the number of threads
     * scales up.
     *
     * @throws InterruptedException
     */
    @Test
    public void testScalingThreadPoolExecutor() throws InterruptedException {
      int CORE_POOL_SIZE = 2;
      int MAX_POOL_SIZE = 10;
      int TASKS_COUNT = 24;
      ThreadPoolExecutor threadPoolExecutor = new ScalingThreadPoolExecutor(CORE_POOL_SIZE,
          MAX_POOL_SIZE, 30000, TimeUnit.MILLISECONDS, CORE_POOL_SIZE);
      BufferedThreadPoolExecutorCompletionService<Runnable> service = new BufferedThreadPoolExecutorCompletionService<>(threadPoolExecutor);
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        service.submit(new Runnable() {
          @Override
          public void run() {
            try {
              longOp();
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
          }
        }, null);
      }
  
      // While waiting for tasks completion, check how many threads are being used
      Thread.sleep(500);
      Assert.assertEquals(MAX_POOL_SIZE, threadPoolExecutor.getActiveCount());
      for (int tc = 0; tc < TASKS_COUNT; tc++) {
        Future<Runnable> take = service.take();
        Assert.assertTrue(take.isDone());
        Assert.assertTrue("No more than MAX_POOL_SIZE threads should be launched", threadPoolExecutor.getActiveCount() <= MAX_POOL_SIZE);
      }
      threadPoolExecutor.shutdown();
    }
  }
  