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.bookkeeper.common.util;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.TimeUnit;
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Test;
  
  /**
   * Tests for {@link MemoryLimitController}.
   */
  public class MemoryLimitControllerTest {
  
      private ExecutorService executor;
  
      @Before
      public void setup() {
          executor = Executors.newCachedThreadPool();
      }
  
      @After
      public void teardown() {
          executor.shutdownNow();
      }
  
      @Test
      public void testLimit() throws Exception {
          MemoryLimitController mlc = new MemoryLimitController(100);
  
          for (int i = 0; i < 101; i++) {
              mlc.reserveMemory(1);
          }
  
          assertEquals(101, mlc.currentUsage());
          assertFalse(mlc.tryReserveMemory(1));
          mlc.releaseMemory(1);
          assertEquals(100, mlc.currentUsage());
  
          assertTrue(mlc.tryReserveMemory(1));
          assertEquals(101, mlc.currentUsage());
      }
  
      @Test
      public void testBlocking() throws Exception {
          MemoryLimitController mlc = new MemoryLimitController(100);
  
          for (int i = 0; i < 101; i++) {
              mlc.reserveMemory(1);
          }
  
          CountDownLatch l1 = new CountDownLatch(1);
          executor.submit(() -> {
              try {
                  mlc.reserveMemory(1);
                  l1.countDown();
              } catch (InterruptedException e) {
              }
          });
  
          CountDownLatch l2 = new CountDownLatch(1);
          executor.submit(() -> {
              try {
                  mlc.reserveMemory(1);
                  l2.countDown();
              } catch (InterruptedException e) {
              }
          });
  
          CountDownLatch l3 = new CountDownLatch(1);
          executor.submit(() -> {
              try {
                  mlc.reserveMemory(1);
                  l3.countDown();
              } catch (InterruptedException e) {
              }
          });
  
          // The threads are blocked since the quota is full
          assertFalse(l1.await(100, TimeUnit.MILLISECONDS));
          assertFalse(l2.await(100, TimeUnit.MILLISECONDS));
          assertFalse(l3.await(100, TimeUnit.MILLISECONDS));
  
          assertEquals(101, mlc.currentUsage());
          mlc.releaseMemory(3);
  
          assertTrue(l1.await(1, TimeUnit.SECONDS));
          assertTrue(l2.await(1, TimeUnit.SECONDS));
          assertTrue(l3.await(1, TimeUnit.SECONDS));
          assertEquals(101, mlc.currentUsage());
      }
  
      @Test
      public void testStepRelease() throws Exception {
          MemoryLimitController mlc = new MemoryLimitController(100);
  
          for (int i = 0; i < 101; i++) {
              mlc.reserveMemory(1);
          }
  
          CountDownLatch l1 = new CountDownLatch(1);
          executor.submit(() -> {
              try {
                  mlc.reserveMemory(1);
                  l1.countDown();
              } catch (InterruptedException e) {
              }
          });
  
          CountDownLatch l2 = new CountDownLatch(1);
          executor.submit(() -> {
              try {
                  mlc.reserveMemory(1);
                  l2.countDown();
              } catch (InterruptedException e) {
              }
          });
  
          CountDownLatch l3 = new CountDownLatch(1);
          executor.submit(() -> {
              try {
                  mlc.reserveMemory(1);
                  l3.countDown();
              } catch (InterruptedException e) {
              }
          });
  
          // The threads are blocked since the quota is full
          assertFalse(l1.await(100, TimeUnit.MILLISECONDS));
          assertFalse(l2.await(100, TimeUnit.MILLISECONDS));
          assertFalse(l3.await(100, TimeUnit.MILLISECONDS));
  
          assertEquals(101, mlc.currentUsage());
  
          mlc.releaseMemory(1);
          mlc.releaseMemory(1);
          mlc.releaseMemory(1);
  
          assertTrue(l1.await(1, TimeUnit.SECONDS));
          assertTrue(l2.await(1, TimeUnit.SECONDS));
          assertTrue(l3.await(1, TimeUnit.SECONDS));
          assertEquals(101, mlc.currentUsage());
      }
  }