| /* |
| * 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.commons.math4.analysis.integration.gauss; |
| |
| import java.util.List; |
| import java.util.ArrayList; |
| import java.util.concurrent.ThreadPoolExecutor; |
| import java.util.concurrent.ArrayBlockingQueue; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| import org.apache.commons.math4.util.Pair; |
| import org.junit.Test; |
| import org.junit.Assert; |
| |
| /** |
| * Test for {@link BaseRuleFactory}. |
| * |
| */ |
| public class BaseRuleFactoryTest { |
| /** |
| * Tests that a given rule rule will be computed and added once to the cache |
| * whatever the number of times this rule is called concurrently. |
| */ |
| @Test |
| public void testConcurrentCreation() throws InterruptedException, |
| ExecutionException { |
| // Number of times the same rule will be called. |
| final int numTasks = 20; |
| |
| final ThreadPoolExecutor exec |
| = new ThreadPoolExecutor(3, numTasks, 1, TimeUnit.SECONDS, |
| new ArrayBlockingQueue<Runnable>(2)); |
| |
| final List<Future<Pair<double[], double[]>>> results |
| = new ArrayList<>(); |
| for (int i = 0; i < numTasks; i++) { |
| results.add(exec.submit(new RuleBuilder())); |
| } |
| |
| // Ensure that all computations have completed. |
| for (Future<Pair<double[], double[]>> f : results) { |
| f.get(); |
| } |
| |
| // Assertion would fail if "getRuleInternal" were not "synchronized". |
| final int n = RuleBuilder.getNumberOfCalls(); |
| Assert.assertEquals("Rule computation was called " + n + " times", 1, n); |
| } |
| } |
| |
| class RuleBuilder implements Callable<Pair<double[], double[]>> { |
| private static final DummyRuleFactory factory = new DummyRuleFactory(); |
| |
| @Override |
| public Pair<double[], double[]> call() { |
| final int dummy = 2; // Always request the same rule. |
| return factory.getRule(dummy); |
| } |
| |
| public static int getNumberOfCalls() { |
| return factory.getNumberOfCalls(); |
| } |
| } |
| |
| class DummyRuleFactory extends BaseRuleFactory<Double> { |
| /** Rule computations counter. */ |
| private static AtomicInteger nCalls = new AtomicInteger(); |
| |
| @Override |
| protected Pair<Double[], Double[]> computeRule(int order) { |
| // Tracks whether this computation has been called more than once. |
| nCalls.getAndIncrement(); |
| |
| try { |
| // Sleep to simulate computation time. |
| Thread.sleep(20); |
| } catch (InterruptedException e) { |
| Assert.fail("Unexpected interruption"); |
| } |
| |
| // Dummy rule (but contents must exist). |
| final Double[] p = new Double[order]; |
| final Double[] w = new Double[order]; |
| for (int i = 0; i < order; i++) { |
| p[i] = new Double(i); |
| w[i] = new Double(i); |
| } |
| return new Pair<>(p, w); |
| } |
| |
| public int getNumberOfCalls() { |
| return nCalls.get(); |
| } |
| } |