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.assertTrue;
  import static org.mockito.ArgumentMatchers.anyInt;
  import static org.mockito.ArgumentMatchers.eq;
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.times;
  import static org.mockito.Mockito.verify;
  
  import java.util.function.Function;
  import org.apache.bookkeeper.common.collections.RecyclableArrayList.Recycler;
  import org.junit.After;
  import org.junit.Test;
  
  /**
   * Unit test of {@link Watchable}.
   */
  public class TestWatchable {
  
      private final Recycler<Watcher<Integer>> recycler;
      private final Watchable<Integer> watchable;
  
      public TestWatchable() {
          this.recycler = new Recycler<>();
          this.watchable = new Watchable<>(recycler);
      }
  
      @After
      public void teardown() {
          this.watchable.recycle();
      }
  
      @Test
      @SuppressWarnings("unchecked")
      public void testAddWatcher() {
          Watcher<Integer> watcher = mock(Watcher.class);
          assertTrue(watchable.addWatcher(watcher));
          assertEquals(1, watchable.getNumWatchers());
  
          watchable.notifyWatchers(Function.identity(), 123);
          verify(watcher, times(1)).update(eq(123));
  
          // after the watcher is fired, watcher should be removed from watcher list.
          assertEquals(0, watchable.getNumWatchers());
      }
  
      @Test
      @SuppressWarnings("unchecked")
      public void testDeleteWatcher() {
          Watcher<Integer> watcher = mock(Watcher.class);
          assertTrue(watchable.addWatcher(watcher));
          assertEquals(1, watchable.getNumWatchers());
          assertTrue(watchable.deleteWatcher(watcher));
          assertEquals(0, watchable.getNumWatchers());
  
          watchable.notifyWatchers(Function.identity(), 123);
          verify(watcher, times(0)).update(anyInt());
      }
  
      @Test
      @SuppressWarnings("unchecked")
      public void testMultipleWatchers() {
          Watcher<Integer> watcher1 = mock(Watcher.class);
          Watcher<Integer> watcher2 = mock(Watcher.class);
  
          assertTrue(watchable.addWatcher(watcher1));
          assertTrue(watchable.addWatcher(watcher2));
          assertEquals(2, watchable.getNumWatchers());
  
          watchable.notifyWatchers(Function.identity(), 123);
          verify(watcher1, times(1)).update(eq(123));
          verify(watcher2, times(1)).update(eq(123));
          assertEquals(0, watchable.getNumWatchers());
      }
  
      @Test
      @SuppressWarnings("unchecked")
      public void testAddWatchMultipleTimes() {
          Watcher<Integer> watcher = mock(Watcher.class);
  
          int numTimes = 3;
          for (int i = 0; i < numTimes; i++) {
              assertTrue(watchable.addWatcher(watcher));
          }
          assertEquals(numTimes, watchable.getNumWatchers());
  
          watchable.notifyWatchers(Function.identity(), 123);
          verify(watcher, times(numTimes)).update(eq(123));
          assertEquals(0, watchable.getNumWatchers());
      }
  
      @Test
      @SuppressWarnings("unchecked")
      public void testDeleteWatchers() {
          Watcher<Integer> watcher1 = mock(Watcher.class);
          Watcher<Integer> watcher2 = mock(Watcher.class);
  
          assertTrue(watchable.addWatcher(watcher1));
          assertTrue(watchable.addWatcher(watcher2));
          assertEquals(2, watchable.getNumWatchers());
          watchable.deleteWatchers();
          assertEquals(0, watchable.getNumWatchers());
  
          watchable.notifyWatchers(Function.identity(), 123);
          verify(watcher1, times(0)).update(anyInt());
          verify(watcher2, times(0)).update(anyInt());
      }
  
  }
  