alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (AbstractConcurrentInitializerTest.java)

This example Java source code file (AbstractConcurrentInitializerTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

abstractconcurrentinitializertest, concurrentexception, concurrentinitializer, countdownlatch, getthread, got, interruptedexception, object, override, test, threading, threads, wrong

The AbstractConcurrentInitializerTest.java Java example source code

/*
 * 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.lang3.concurrent;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;

import java.util.concurrent.CountDownLatch;

import org.junit.Test;

/**
 * <p>
 * An abstract base class for tests of concrete {@code ConcurrentInitializer}
 * implementations.
 * </p>
 * <p>
 * This class provides some basic tests for initializer implementations. Derived
 * class have to create a {@link ConcurrentInitializer} object on which the
 * tests are executed.
 * </p>
 */
public abstract class AbstractConcurrentInitializerTest {
    /**
     * Tests a simple invocation of the get() method.
     *
     * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it
     */
    @Test
    public void testGet() throws ConcurrentException {
        assertNotNull("No managed object", createInitializer().get());
    }

    /**
     * Tests whether sequential get() invocations always return the same
     * instance.
     *
     * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it
     */
    @Test
    public void testGetMultipleTimes() throws ConcurrentException {
        final ConcurrentInitializer<Object> initializer = createInitializer();
        final Object obj = initializer.get();
        for (int i = 0; i < 10; i++) {
            assertEquals("Got different object at " + i, obj, initializer.get());
        }
    }

    /**
     * Tests whether get() can be invoked from multiple threads concurrently.
     * Always the same object should be returned.
     *
     * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it
     * @throws java.lang.InterruptedException because the threading API my throw it
     */
    @Test
    public void testGetConcurrent() throws ConcurrentException,
            InterruptedException {
        final ConcurrentInitializer<Object> initializer = createInitializer();
        final int threadCount = 20;
        final CountDownLatch startLatch = new CountDownLatch(1);
        class GetThread extends Thread {
            Object object;

            @Override
            public void run() {
                try {
                    // wait until all threads are ready for maximum parallelism
                    startLatch.await();
                    // access the initializer
                    object = initializer.get();
                } catch (final InterruptedException iex) {
                    // ignore
                } catch (final ConcurrentException cex) {
                    object = cex;
                }
            }
        }

        final GetThread[] threads = new GetThread[threadCount];
        for (int i = 0; i < threadCount; i++) {
            threads[i] = new GetThread();
            threads[i].start();
        }

        // fire all threads and wait until they are ready
        startLatch.countDown();
        for (final Thread t : threads) {
            t.join();
        }

        // check results
        final Object managedObject = initializer.get();
        for (final GetThread t : threads) {
            assertEquals("Wrong object", managedObject, t.object);
        }
    }

    /**
     * Creates the {@link ConcurrentInitializer} object to be tested. This
     * method is called whenever the test fixture needs to be obtained.
     *
     * @return the initializer object to be tested
     */
    protected abstract ConcurrentInitializer<Object> createInitializer();
}

Other Java examples (source code examples)

Here is a short list of links related to this Java AbstractConcurrentInitializerTest.java source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.