ConcurrentGetWhenPutTestCase.java

/*
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.commons.cache.future;

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.concurrent.Callable;

import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

import org.gatein.common.util.Tools;

/**
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 * @version $Revision$
 */
public class ConcurrentGetWhenPutTestCase extends TestCase {

    /** . */
    private AssertionFailedError failure;

    /** . */
    private List<String> events = Collections.synchronizedList(new LinkedList<String>());

    FutureCache<String, String, Callable<String>> futureCache = new FutureCache<String, String, Callable<String>>(
            new StringLoader()) {

        @Override
        protected String get(String key) {
            if (key == key1) {
                if (Thread.currentThread() != thread1) {
                    failure = new AssertionFailedError();
                }
                events.add("get/key1");
            } else if (key == key2) {
                if (Thread.currentThread() != thread2) {
                    failure = new AssertionFailedError();
                }
                events.add("get/key2");
            } else {
                failure = new AssertionFailedError();
            }
            return null;
        }

        @Override
        protected void put(String key, String value) {
            if (key == key1) {
                if (Thread.currentThread() == thread1) {
                    events.add("begin_put/key1/" + value);

                    //
                    thread2.start();

                    //
                    while (thread2.getState() != Thread.State.WAITING) {
                        // Wait until thread 2 is blocked
                    }

                    //
                    events.add("end_put/key1");
                } else {
                    failure = new AssertionFailedError();
                }
            } else {
                failure = new AssertionFailedError();
            }
        }
    };

    /** . */
    private final String key1 = new String("foo");

    /** . */
    private final String key2 = new String("foo");

    Thread thread1 = new Thread() {
        @Override
        public void run() {
            String v = futureCache.get(new Callable<String>() {
                public String call() throws Exception {
                    events.add("call/key1");
                    return "foo_value_1";
                }
            }, key1);
            events.add("retrieved/key1/" + v);
        }
    };

    Thread thread2 = new Thread() {
        @Override
        public void run() {
            String v = futureCache.get(new Callable<String>() {
                public String call() throws Exception {
                    failure = new AssertionFailedError();
                    return "foo_value_2";
                }
            }, key2);
            events.add("retrieved/key2/" + v);
        }
    };

    public void testMain() throws Exception {
        thread1.start();

        //
        thread1.join();
        thread2.join();

        //
        if (failure != null) {
            throw failure;
        }

        //
        List<String> expectedEvents = Arrays.asList("get/key1", "call/key1", "begin_put/key1/foo_value_1", "get/key2",
                "end_put/key1");

        //
        assertEquals(expectedEvents, events.subList(0, expectedEvents.size()));

        //
        Set<String> expectedEndEvents = Tools.toSet("retrieved/key1/foo_value_1", "retrieved/key2/foo_value_1");
        assertEquals(expectedEndEvents, new HashSet<String>(events.subList(expectedEvents.size(), events.size())));
    }

}