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/*
* Copyright (C) 2011 The Guava Authors
*
* Licensed 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 com.google.common.collect;
import com.google.common.base.Function;
import com.google.common.primitives.Ints;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;
/**
* Basher test for {@link ConcurrentHashMultiset}: start a bunch of threads, have each of them do
* operations at random. Each thread keeps track of the per-key deltas that it's directly
* responsible for; after all threads have completed, we sum the per-key deltas and compare to the
* existing multiset values.
*
* @author mike nonemacher
*/
public class ConcurrentHashMultisetBasherTest extends TestCase {
public void testAddAndRemove_ConcurrentHashMap() throws Exception {
testAddAndRemove(new ConcurrentHashMap<String, AtomicInteger>());
}
public void testAddAndRemove_ConcurrentSkipListMap() throws Exception {
testAddAndRemove(new ConcurrentSkipListMap<String, AtomicInteger>());
}
public void testAddAndRemove_MapMakerMap() throws Exception {
MapMaker mapMaker = new MapMaker();
// force MapMaker to use its own MapMakerInternalMap
mapMaker.useCustomMap = true;
testAddAndRemove(mapMaker.<String, AtomicInteger>makeMap());
}
private void testAddAndRemove(ConcurrentMap<String, AtomicInteger> map)
throws ExecutionException, InterruptedException {
final ConcurrentHashMultiset<String> multiset = new ConcurrentHashMultiset<>(map);
int nThreads = 20;
int tasksPerThread = 10;
int nTasks = nThreads * tasksPerThread;
ExecutorService pool = Executors.newFixedThreadPool(nThreads);
ImmutableList<String> keys = ImmutableList.of("a", "b", "c");
try {
List<Future<int[]>> futures = Lists.newArrayListWithExpectedSize(nTasks);
for (int i = 0; i < nTasks; i++) {
futures.add(pool.submit(new MutateTask(multiset, keys)));
}
int[] deltas = new int[3];
for (Future<int[]> future : futures) {
int[] taskDeltas = future.get();
for (int i = 0; i < deltas.length; i++) {
deltas[i] += taskDeltas[i];
}
}
List<Integer> actualCounts =
Lists.transform(
keys,
new Function<String, Integer>() {
@Override
public Integer apply(String key) {
return multiset.count(key);
}
});
assertEquals("Counts not as expected", Ints.asList(deltas), actualCounts);
} finally {
pool.shutdownNow();
}
// Since we have access to the backing map, verify that there are no zeroes in the map
for (AtomicInteger value : map.values()) {
assertTrue("map should not contain a zero", value.get() != 0);
}
}
private static class MutateTask implements Callable<int[]> {
private final ConcurrentHashMultiset<String> multiset;
private final ImmutableList<String> keys;
private final Random random = new Random();
private MutateTask(ConcurrentHashMultiset<String> multiset, ImmutableList<String> keys) {
this.multiset = multiset;
this.keys = keys;
}
@Override
public int[] call() throws Exception {
int iterations = 100000;
int nKeys = keys.size();
int[] deltas = new int[nKeys];
Operation[] operations = Operation.values();
for (int i = 0; i < iterations; i++) {
int keyIndex = random.nextInt(nKeys);
String key = keys.get(keyIndex);
Operation op = operations[random.nextInt(operations.length)];
switch (op) {
case ADD:
{
int delta = random.nextInt(10);
multiset.add(key, delta);
deltas[keyIndex] += delta;
break;
}
case SET_COUNT:
{
int newValue = random.nextInt(3);
int oldValue = multiset.setCount(key, newValue);
deltas[keyIndex] += (newValue - oldValue);
break;
}
case SET_COUNT_IF:
{
int newValue = random.nextInt(3);
int oldValue = multiset.count(key);
if (multiset.setCount(key, oldValue, newValue)) {
deltas[keyIndex] += (newValue - oldValue);
}
break;
}
case REMOVE:
{
int delta = random.nextInt(6); // [0, 5]
int oldValue = multiset.remove(key, delta);
deltas[keyIndex] -= Math.min(delta, oldValue);
break;
}
case REMOVE_EXACTLY:
{
int delta = random.nextInt(5); // [0, 4]
if (multiset.removeExactly(key, delta)) {
deltas[keyIndex] -= delta;
}
break;
}
}
}
return deltas;
}
private enum Operation {
ADD,
SET_COUNT,
SET_COUNT_IF,
REMOVE,
REMOVE_EXACTLY,
;
}
}
}
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