/*
* 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.accumulo.core.util;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.junit.Assert;
import org.junit.Test;
public class CompletableFutureUtilTest {
@Test
public void testMerge() throws Exception {
ExecutorService es = Executors.newFixedThreadPool(3);
try {
for (int n : new int[] {1, 2, 3, 997, 1000}) {
List<CompletableFuture<Integer>> futures = new ArrayList<>();
for (int i = 1; i <= n; i++) {
final int num = i;
futures.add(CompletableFuture.supplyAsync(() -> num, es));
}
CompletableFuture<Integer> mergedFutures = CompletableFutureUtil.merge(futures, Integer::sum, () -> 0);
Assert.assertEquals(n * (n + 1) / 2, mergedFutures.get().intValue());
}
// test zero
CompletableFuture<Integer> mergedFutures = CompletableFutureUtil.merge(Collections.emptyList(), Integer::sum, () -> 0);
Assert.assertEquals(0, mergedFutures.get().intValue());
} finally {
es.shutdown();
}
}
}