foundation/eclipselink.core.test/src/test/java/org/eclipse/persistence/testing/tests/junit/helper/ConcurrencySemaphoreTest.java

/*
 * Copyright (c) 2021 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Oracle - initial API and implementation
package org.eclipse.persistence.testing.tests.junit.helper;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import org.eclipse.persistence.internal.helper.ConcurrencyUtil;
import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.assertEquals;


public class ConcurrencySemaphoreTest {

    private static final int INITIAL_NO_OF_THREADS = 100;
    private static final long MAX_TIME_PERMIT = 500L;
    private static final long TIMEOUT_BETWEEN_LOG_MESSAGES = 20000L;

    @Before
    public void setup() {
        //This kind of setup is for test purpose only. Standard way is via persistence.xml properties or system properties.
        ConcurrencyUtil.SINGLETON.setConcurrencySemaphoreMaxTimePermit(MAX_TIME_PERMIT);
        ConcurrencyUtil.SINGLETON.setConcurrencySemaphoreLogTimeout(TIMEOUT_BETWEEN_LOG_MESSAGES);
    }

    @Test
    public void testConcurrencySemaphore() throws Exception {
        //Verify setup
        assertEquals(MAX_TIME_PERMIT, ConcurrencyUtil.SINGLETON.getConcurrencySemaphoreMaxTimePermit());
        assertEquals(TIMEOUT_BETWEEN_LOG_MESSAGES, ConcurrencyUtil.SINGLETON.getConcurrencySemaphoreLogTimeout());
        //Prepare executor and start threads
        ExecutorService executorService = Executors.newFixedThreadPool(INITIAL_NO_OF_THREADS);
        for (int i = 1; i <= INITIAL_NO_OF_THREADS; i++) {
            Runnable thread = new ConcurrencySemaphoreThread();
            executorService.execute(thread);
        }
        executorService.shutdown();
        // Wait for everything to finish.
        while (!executorService.awaitTermination(20, TimeUnit.SECONDS)) {
            System.out.println("Awaiting completion of threads.");
        }
    }
}