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.Random;
029import java.util.concurrent.CompletableFuture;
030import java.util.concurrent.CompletionException;
031import java.util.concurrent.ExecutionException;
032import java.util.concurrent.ThreadLocalRandom;
033import java.util.concurrent.atomic.AtomicInteger;
034import org.apache.hadoop.hbase.HBaseClassTestRule;
035import org.apache.hadoop.hbase.testclassification.MiscTests;
036import org.apache.hadoop.hbase.testclassification.SmallTests;
037import org.apache.hadoop.hbase.util.PoolMap.PoolType;
038import org.junit.ClassRule;
039import org.junit.Test;
040import org.junit.experimental.categories.Category;
041
042@Category({ MiscTests.class, SmallTests.class })
043public class TestRoundRobinPoolMap extends PoolMapTestBase {
044
045  @ClassRule
046  public static final HBaseClassTestRule CLASS_RULE =
047      HBaseClassTestRule.forClass(TestRoundRobinPoolMap.class);
048
049  @Override
050  protected PoolType getPoolType() {
051    return PoolType.RoundRobin;
052  }
053
054  @Test
055  public void testGetOrCreate() throws IOException {
056    String key = "key";
057    String value = "value";
058    String result = poolMap.getOrCreate(key, () -> value);
059
060    assertEquals(value, result);
061    assertEquals(1, poolMap.values().size());
062  }
063
064  @Test
065  public void testMultipleKeys() throws IOException {
066    for (int i = 0; i < KEY_COUNT; i++) {
067      String key = Integer.toString(i);
068      String value = Integer.toString(2 * i);
069      String result = poolMap.getOrCreate(key, () -> value);
070
071      assertEquals(value, result);
072    }
073
074    assertEquals(KEY_COUNT, poolMap.values().size());
075  }
076
077  @Test
078  public void testMultipleValues() throws IOException {
079    String key = "key";
080
081    for (int i = 0; i < POOL_SIZE; i++) {
082      String value = Integer.toString(i);
083      String result = poolMap.getOrCreate(key, () -> value);
084
085      assertEquals(value, result);
086    }
087
088    assertEquals(POOL_SIZE, poolMap.values().size());
089  }
090
091  @Test
092  public void testRoundRobin() throws IOException {
093    String key = "key";
094
095    for (int i = 0; i < POOL_SIZE; i++) {
096      String value = Integer.toString(i);
097      poolMap.getOrCreate(key, () -> value);
098    }
099
100    assertEquals(POOL_SIZE, poolMap.values().size());
101
102    /* pool is filled, get() should return elements round robin order */
103    for (int i = 0; i < 2 * POOL_SIZE; i++) {
104      String expected = Integer.toString(i % POOL_SIZE);
105      assertEquals(expected, poolMap.getOrCreate(key, () -> {
106        throw new IOException("must not call me");
107      }));
108    }
109
110    assertEquals(POOL_SIZE, poolMap.values().size());
111  }
112
113  @Test
114  public void testMultiThreadedRoundRobin() throws ExecutionException, InterruptedException {
115    String key = "key";
116    AtomicInteger id = new AtomicInteger();
117    List<String> results = Collections.synchronizedList(new ArrayList<>());
118
119    Runnable runnable = () -> {
120      try {
121        for (int i = 0; i < POOL_SIZE; i++) {
122          String value = Integer.toString(id.getAndIncrement());
123          String result = poolMap.getOrCreate(key, () -> value);
124          results.add(result);
125
126          Thread.yield();
127        }
128      } catch (IOException e) {
129        throw new CompletionException(e);
130      }
131    };
132
133    CompletableFuture<Void> future1 = CompletableFuture.runAsync(runnable);
134    CompletableFuture<Void> future2 = CompletableFuture.runAsync(runnable);
135
136    /* test for successful completion */
137    future1.get();
138    future2.get();
139
140    assertEquals(POOL_SIZE, poolMap.values().size());
141
142    /* check every elements occur twice */
143    Collections.sort(results);
144    Iterator<String> iterator = results.iterator();
145
146    for (int i = 0; i < POOL_SIZE; i++) {
147      String next1 = iterator.next();
148      String next2 = iterator.next();
149      assertEquals(next1, next2);
150    }
151
152    assertFalse(iterator.hasNext());
153  }
154}