/*
* org.openmicroscopy.shoola.util.concur.TestProducerLoopSync
*
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* Copyright (C) 2006 University of Dundee. All rights reserved.
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*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
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* This program 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 General Public License for more details.
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* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
package org.openmicroscopy.shoola.util.concur;
//Java imports
//Third-party libraries
import junit.framework.TestCase;
//Application-internal dependencies
/**
* Verifies the safety of {@link ProducerLoop}.
* We test that <code>onCancel</code>, <code>onAbort</code>, and
* <code>onEnd</code> calls are serialized in the presence of
* multiple threads acting on the object.
*
* @see org.openmicroscopy.shoola.util.concur.ThreadSupport
* @author Jean-Marie Burel
* <a href="mailto:j.burel@dundee.ac.uk">j.burel@dundee.ac.uk</a>
* @author <br>Andrea Falconi
* <a href="mailto:a.falconi@dundee.ac.uk">
* a.falconi@dundee.ac.uk</a>
* @version 2.2
* <small>
* (<b>Internal version:</b> $Revision$ $Date$)
* </small>
* @since OME2.2
*/
public class TestProducerLoopSync
extends TestCase
{
private ProducerLoop target; //Object under test.
private int state; //To transfer value from alternate flow.
private ThreadSupport threads; //To manage main/alt flows.
public void setUp()
{
threads = new ThreadSupport(new Runnable() { //Alternate flow.
public void run() { state = target.getState(); }
});
//NOTE: getState() is sync. So if it is called while onCancel/onAbort/
//onEnd is being executed in the main thread, then the alternate thread
//will have to wait until the lock is released. This is enough to test
//safety, there's no need to use more than two threads and verify all
//possible combinations of the sync methods of ProducerLoop.
AsyncByteBuffer buffer = new AsyncByteBuffer(10, 10);
FakeByteBufferFiller producer =
new FakeByteBufferFiller(10, (byte) 1);
target = new ProducerLoop(buffer, producer);
target.register(new ControlFlowObserver() {
public void update(int checkPointID)
{ //Called w/in main thread.
if (checkPointID == ProducerLoop.LOCK_ACQUIRED) {
//onCancel/onAbort/onEnd in progress. Spawn alt thread to
//retrieve target's state.
threads.startAltFlow(); //target.getState() will be called.
threads.pauseMainFlow();
//NOTE: Even though pausing the main flow doesn't guarantee
//that getState() will be invoked in the mean time, the
//2-second delay used should in practice make this extremely
//likely to happen.
}
}
});
//NOTE: If getState() gets executed b/f onCancel/onAbort/onEnd modifies
//the target's state field, then we would also get the wrong value for
//our state field. In this case, we can deduce that locks were screwed
//up and thus fail the test.
//The test would be optimal if we could make sure that getState() is
//actually invoked while onCancel/onAbort/onEnd is being executed (in
//practice this is quite sure though). In any case, pausing the main
//thread is the best we can do as there's no way to tell whether a
//thread is waiting to acquire a lock.
}
public void testOnCancel()
{
//Target's state is FILLING.
//This will call observer, which will spawn alt flow and pause
//main flow. As the main flow is paused, the alt flow will
//retrieve the target's state.
target.onCancel();
//Wait for alt flow to join back so that its memory will be flushed
//and the state value it read will be available to the main flow.
threads.awaitAltFlow();
assertEquals("Concurrent access to target's state.",
ProducerLoop.DATA_DISCARDED, state);
}
public void testOnAbort()
{
//Target's state is FILLING.
//This will call observer, which will spawn alt flow and pause
//main flow. As the main flow is paused, the alt flow will
//retrieve the target's state.
target.onAbort(new BufferWriteException(""));
//Wait for alt flow to join back so that its memory will be flushed
//and the state value it read will be available to the main flow.
threads.awaitAltFlow();
assertEquals("Concurrent access to target's state.",
ProducerLoop.DATA_DISCARDED, state);
}
public void testOnEnd()
{
//Target's state is FILLING.
//This will call observer, which will spawn alt flow and pause
//main flow. As the main flow is paused, the alt flow will
//retrieve the target's state.
target.onEnd(null);
//Wait for alt flow to join back so that its memory will be flushed
//and the state value it read will be available to the main flow.
threads.awaitAltFlow();
assertEquals("Concurrent access to target's state.",
ProducerLoop.DATA_DISCARDED, state);
}
}