/*
* org.openmicroscopy.shoola.env.data.events.DSCallAdapter
*
*------------------------------------------------------------------------------
* 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.env.data.events;
//Java imports
//Third-party libraries
//Application-internal dependencies
import org.openmicroscopy.shoola.env.event.AgentEvent;
import org.openmicroscopy.shoola.env.event.AgentEventListener;
/**
* Adapter class for receiving {@link DSCallFeedbackEvent}s and
* {@link DSCallOutcomeEvent}s.
* <p>The purpose of this class is to ease the job of creating observers for
* asynchronous calls to the data services. This class implements the
* {@link AgentEventListener} interface and forwards every feedback event to the
* {@link #update(DSCallFeedbackEvent) update} method. When the notification of
* the computation outcome is received (that is, a {@link DSCallFeedbackEvent}),
* the {@link #onEnd() onEnd} method is called, then right after one of the
* <code>handleXXX</code> methods is called depending on what was the
* computation outcome — note that the <code>handleXXX</code> methods are
* mutually exclusive, only one will ever be invoked.</p>
* <p>This class provides a default <i>no-op</i> implementation of the
* <code>update</code>, <code>onEnd</code>, and <code>handleXXX</code> methods
* so that subclasses can override only those methods they care about.</p>
*
* @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 abstract class DSCallAdapter
implements AgentEventListener
{
/**
* Invokes one of the methods in this class according to the received
* <code>DSCall</code> event.
*
* @see AgentEventListener#eventFired(AgentEvent)
*/
public final void eventFired(AgentEvent ae)
{
if (ae instanceof DSCallFeedbackEvent) { //Progress notification.
update((DSCallFeedbackEvent) ae);
} else { //Outcome notification.
DSCallOutcomeEvent oe = (DSCallOutcomeEvent) ae;
onEnd();
switch (oe.getState()) {
case DSCallOutcomeEvent.CANCELLED:
handleCancellation();
break;
case DSCallOutcomeEvent.ERROR:
handleException(oe.getException());
break;
case DSCallOutcomeEvent.NO_RESULT:
handleNullResult();
break;
case DSCallOutcomeEvent.HAS_RESULT:
handleResult(oe.getResult());
}
}
//Ignore any other event.
}
/**
* Invoked when a progress notification is received.
*
* @param progress Embodies the progress notification.
*/
public void update(DSCallFeedbackEvent progress) {}
/**
* Invoked when the call returns.
* This method is called upon receiving the {@link DSCallOutcomeEvent},
* but before any of the <code>handleXXX</code> is invoked.
*/
public void onEnd() {}
/**
* Invoked if the call returns normally with a non-<code>null</code>
* return value.
* This happens when the state of the received {@link DSCallOutcomeEvent}
* is {@link DSCallOutcomeEvent#HAS_RESULT HAS_RESULT}.
*
* @param result The result of the call. It's a non-<code>null</code>
* reference that you'll have to cast to a more suitable
* type as documented by the call.
*/
public void handleResult(Object result) {}
/**
* Invoked if the call returns with a <code>null</code> value.
* This happens when the state of the received {@link DSCallOutcomeEvent}
* is {@link DSCallOutcomeEvent#NO_RESULT NO_RESULT}.
*/
public void handleNullResult() {}
/**
* Invoked if the call was cancelled.
* This happens when the state of the received {@link DSCallOutcomeEvent}
* is {@link DSCallOutcomeEvent#CANCELLED CANCELLED}.
*
*/
public void handleCancellation() {}
/**
* Invoked if the call raised an exception.
* This happens when the state of the received {@link DSCallOutcomeEvent}
* is {@link DSCallOutcomeEvent#ERROR ERROR}.
* The <code>exc</code> argument is a non-<code>null</code> reference that
* you'll have to cast to a more suitable type as documented by the call.
* However, keep in mind that other exceptions are possible besides those
* documented by the call. In fact, <i>any</i> exception occurred during
* the computation will be caught and eventually dispatched to this method.
*
* @param exc The exception that was thrown.
*/
public void handleException(Throwable exc) {}
}