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/*
* Copyright (C) 2017 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.cache;
import static com.google.common.truth.Truth.assertThat;
import java.util.concurrent.TimeUnit;
import java.util.function.IntConsumer;
import java.util.stream.IntStream;
import junit.framework.TestCase;
/** Test Java8 map.compute in concurrent cache context. */
public class LocalCacheMapComputeTest extends TestCase {
final int count = 10000;
final String delimiter = "-";
final String key = "key";
Cache<String, String> cache;
// helper
private static void doParallelCacheOp(int count, IntConsumer consumer) {
IntStream.range(0, count).parallel().forEach(consumer);
}
@Override
public void setUp() throws Exception {
super.setUp();
this.cache =
CacheBuilder.newBuilder()
.expireAfterAccess(500000, TimeUnit.MILLISECONDS)
.maximumSize(count)
.build();
}
public void testComputeIfAbsent() {
// simultaneous insertion for same key, expect 1 winner
doParallelCacheOp(
count,
n -> {
cache.asMap().computeIfAbsent(key, k -> "value" + n);
});
assertEquals(1, cache.size());
}
public void testComputeIfAbsentEviction() {
// b/80241237
Cache<String, String> c = CacheBuilder.newBuilder().maximumSize(1).build();
assertThat(c.asMap().computeIfAbsent("hash-1", k -> "")).isEqualTo("");
assertThat(c.asMap().computeIfAbsent("hash-1", k -> "")).isEqualTo("");
assertThat(c.asMap().computeIfAbsent("hash-1", k -> "")).isEqualTo("");
assertThat(c.size()).isEqualTo(1);
assertThat(c.asMap().computeIfAbsent("hash-2", k -> "")).isEqualTo("");
}
public void testComputeEviction() {
// b/80241237
Cache<String, String> c = CacheBuilder.newBuilder().maximumSize(1).build();
assertThat(c.asMap().compute("hash-1", (k, v) -> "a")).isEqualTo("a");
assertThat(c.asMap().compute("hash-1", (k, v) -> "b")).isEqualTo("b");
assertThat(c.asMap().compute("hash-1", (k, v) -> "c")).isEqualTo("c");
assertThat(c.size()).isEqualTo(1);
assertThat(c.asMap().computeIfAbsent("hash-2", k -> "")).isEqualTo("");
}
public void testComputeIfPresent() {
cache.put(key, "1");
// simultaneous update for same key, expect count successful updates
doParallelCacheOp(
count,
n -> {
cache.asMap().computeIfPresent(key, (k, v) -> v + delimiter + n);
});
assertEquals(1, cache.size());
assertThat(cache.getIfPresent(key).split(delimiter)).hasLength(count + 1);
}
public void testUpdates() {
cache.put(key, "1");
// simultaneous update for same key, some null, some non-null
doParallelCacheOp(
count,
n -> {
cache.asMap().compute(key, (k, v) -> n % 2 == 0 ? v + delimiter + n : null);
});
assertTrue(1 >= cache.size());
}
public void testCompute() {
cache.put(key, "1");
// simultaneous deletion
doParallelCacheOp(
count,
n -> {
cache.asMap().compute(key, (k, v) -> null);
});
assertEquals(0, cache.size());
}
public void testComputeExceptionally() {
try {
doParallelCacheOp(count, n -> {
cache.asMap().compute(key, (k, v) -> { throw new RuntimeException(); });
});
fail("Should not get here");
} catch (RuntimeException ex) {
}
}
}
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