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.cassandra.hints;
  
  import org.apache.cassandra.Util;
  import org.jboss.byteman.contrib.bmunit.BMRule;
  import org.jboss.byteman.contrib.bmunit.BMUnitRunner;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.Queue;
  import java.util.UUID;
  import java.util.concurrent.ConcurrentLinkedQueue;
  
  import static org.junit.Assert.assertTrue;
  
  @RunWith(BMUnitRunner.class)
  public class HintsBufferPoolTest
  {
  
      @BeforeClass
      public static void defineSchema()
      {
          HintsBufferTest.defineSchema();
      }
  
      /*
       * Check that the hints buffer pool will only drain a limited number of buffers
       */
      static volatile boolean blockedOnBackpressure = false;
      @Test
      @BMRule(name = "Greatest name in the world",
              targetClass="HintsBufferPool",
              targetMethod="switchCurrentBuffer",
              targetLocation="AT INVOKE java.util.concurrent.BlockingQueue.take",
              action="org.apache.cassandra.hints.HintsBufferPoolTest.blockedOnBackpressure = true;")
      public void testBackpressure() throws Exception
      {
          Queue<HintsBuffer> returnedBuffers = new ConcurrentLinkedQueue<>();
          HintsBufferPool pool = new HintsBufferPool(256, (buffer, p) -> returnedBuffers.offer(buffer));
  
          Thread blocked = new Thread(() -> {
              for (int ii = 0; ii < 512; ii++)
                  pool.write(ImmutableList.of(UUID.randomUUID()), HintsBufferTest.createHint(ii, ii));
          });
          blocked.start();
  
          Util.spinAssertEquals(true, () -> blockedOnBackpressure, 60);
  
          while (blocked.isAlive())
              if (!returnedBuffers.isEmpty())
                  pool.offer(returnedBuffers.poll().recycle());
  
          assertTrue(blockedOnBackpressure);
      }
  }
  