/*
* org.openmicroscopy.shoola.util.concur.tasks.TestExecCommandSync
*
*------------------------------------------------------------------------------
* Copyright (C) 2006 University of Dundee. All rights reserved.
*
*
* 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
* (at your option) any later version.
* 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.
*
* 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.
*
*------------------------------------------------------------------------------
*/
package org.openmicroscopy.shoola.util.concur.tasks;
//Java imports
//Third-party libraries
import junit.framework.TestCase;
//Application-internal dependencies
import org.openmicroscopy.shoola.util.concur.ControlFlowObserver;
import org.openmicroscopy.shoola.util.concur.ThreadSupport;
/**
* Verifies the safety of {@link ExecCommand}.
* We test that <code>run</code> and <code>cancel</code> calls are serialized
* in the presence of multiple threads acting on the object.
*
* @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 TestExecCommandSync
extends TestCase
{
private ExecCommand target; //Object to test.
private int tState; //To transfer values from alternate flow.
private int readPointID; //Tells at which point to read tState.
private ThreadSupport threads; //To manage main/alt flows.
public void setUp()
{
threads = new ThreadSupport(new Runnable() { //Alternate flow.
public void run() { tState = target.getState(); }
});
//NOTE: getState() is sync. So if it is called while enterExecuting/
//leaveExecuting/cancel 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 those methods.
Future future = new Future();//Not in a legal state yet (two-step init).
target = new ExecCommand(new TaskAdapter(new Runnable()
{public void run(){}}), new NullResultAssembler(), future,
new NullExecMonitor());
future.setCommand(target); //OK, init completed now.
readPointID = -1;
target.register(new ControlFlowObserver() {
public void update(int checkPointID)
{ //Called w/in main thread.
if (checkPointID == readPointID) {
//get/set in progress. Spawn alt thread to retrieve 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 enterExecuting/leaveExecuting/
//cancel modifies the state, then we would also get the wrong value for
//tState. 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 enterExecuting/leaveExecuting/cancel 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 testEnterExecuting()
{
readPointID = ExecCommand.LOCK_ACQUIRED_BY_ENTER_EXECUTING;
target.run();
threads.awaitAltFlow();
assertTrue("Concurrent access to command state.",
(tState == ExecCommand.EXECUTING ||
tState == ExecCommand.FINISHED));
}
public void testLeaveExecuting()
{
readPointID = ExecCommand.LOCK_ACQUIRED_BY_LEAVE_EXECUTING;
target.run();
threads.awaitAltFlow();
assertEquals("Concurrent access to command state.",
ExecCommand.FINISHED, tState);
}
public void testCancel()
{
readPointID = ExecCommand.LOCK_ACQUIRED_BY_CANCEL;
target.cancel();
threads.awaitAltFlow();
assertEquals("Concurrent access to command state.",
ExecCommand.CANCELLED, tState);
}
}