001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.util;
019
020import static org.junit.Assert.assertEquals;
021import static org.junit.Assert.assertFalse;
022
023import java.io.IOException;
024import java.util.ArrayList;
025import java.util.Collections;
026import java.util.Iterator;
027import java.util.List;
028import java.util.concurrent.CompletableFuture;
029import java.util.concurrent.CompletionException;
030import java.util.concurrent.ExecutionException;
031import java.util.concurrent.atomic.AtomicInteger;
032import org.apache.hadoop.hbase.HBaseClassTestRule;
033import org.apache.hadoop.hbase.testclassification.MiscTests;
034import org.apache.hadoop.hbase.testclassification.SmallTests;
035import org.apache.hadoop.hbase.util.PoolMap.PoolType;
036import org.junit.ClassRule;
037import org.junit.Test;
038import org.junit.experimental.categories.Category;
039
040@Category({ MiscTests.class, SmallTests.class })
041public class TestRoundRobinPoolMap extends PoolMapTestBase {
042
043  @ClassRule
044  public static final HBaseClassTestRule CLASS_RULE =
045    HBaseClassTestRule.forClass(TestRoundRobinPoolMap.class);
046
047  @Override
048  protected PoolType getPoolType() {
049    return PoolType.RoundRobin;
050  }
051
052  @Test
053  public void testGetOrCreate() throws IOException {
054    String key = "key";
055    String value = "value";
056    String result = poolMap.getOrCreate(key, () -> value);
057
058    assertEquals(value, result);
059    assertEquals(1, poolMap.values().size());
060  }
061
062  @Test
063  public void testMultipleKeys() throws IOException {
064    for (int i = 0; i < KEY_COUNT; i++) {
065      String key = Integer.toString(i);
066      String value = Integer.toString(2 * i);
067      String result = poolMap.getOrCreate(key, () -> value);
068
069      assertEquals(value, result);
070    }
071
072    assertEquals(KEY_COUNT, poolMap.values().size());
073  }
074
075  @Test
076  public void testMultipleValues() throws IOException {
077    String key = "key";
078
079    for (int i = 0; i < POOL_SIZE; i++) {
080      String value = Integer.toString(i);
081      String result = poolMap.getOrCreate(key, () -> value);
082
083      assertEquals(value, result);
084    }
085
086    assertEquals(POOL_SIZE, poolMap.values().size());
087  }
088
089  @Test
090  public void testRoundRobin() throws IOException {
091    String key = "key";
092
093    for (int i = 0; i < POOL_SIZE; i++) {
094      String value = Integer.toString(i);
095      poolMap.getOrCreate(key, () -> value);
096    }
097
098    assertEquals(POOL_SIZE, poolMap.values().size());
099
100    /* pool is filled, get() should return elements round robin order */
101    for (int i = 0; i < 2 * POOL_SIZE; i++) {
102      String expected = Integer.toString(i % POOL_SIZE);
103      assertEquals(expected, poolMap.getOrCreate(key, () -> {
104        throw new IOException("must not call me");
105      }));
106    }
107
108    assertEquals(POOL_SIZE, poolMap.values().size());
109  }
110
111  @Test
112  public void testMultiThreadedRoundRobin() throws ExecutionException, InterruptedException {
113    String key = "key";
114    AtomicInteger id = new AtomicInteger();
115    List<String> results = Collections.synchronizedList(new ArrayList<>());
116
117    Runnable runnable = () -> {
118      try {
119        for (int i = 0; i < POOL_SIZE; i++) {
120          String value = Integer.toString(id.getAndIncrement());
121          String result = poolMap.getOrCreate(key, () -> value);
122          results.add(result);
123          // Sleep for a short time to ensure a yield. Thread#yield has platform dependent behavior.
124          Thread.sleep(10);
125        }
126      } catch (Exception e) {
127        throw new CompletionException(e);
128      }
129    };
130
131    CompletableFuture<Void> future1 = CompletableFuture.runAsync(runnable);
132    CompletableFuture<Void> future2 = CompletableFuture.runAsync(runnable);
133
134    /* test for successful completion */
135    future1.get();
136    future2.get();
137
138    assertEquals(POOL_SIZE, poolMap.values().size());
139
140    /* check every elements occur twice */
141    Collections.sort(results);
142    Iterator<String> iterator = results.iterator();
143
144    for (int i = 0; i < POOL_SIZE; i++) {
145      String next1 = iterator.next();
146      String next2 = iterator.next();
147      assertEquals(next1, next2);
148    }
149
150    assertFalse(iterator.hasNext());
151  }
152}