/*
* org.openmicroscopy.shoola.util.concur.tasks.MultiStepTask
*
*------------------------------------------------------------------------------
* 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
//Application-internal dependencies
/**
* Models a computation that is broken down into subsequent steps.
* Each step is carried out by the {@link #doStep() doStep} method and supplies
* a partial result of the computation. The computation result has to be
* assembled out of those partial results. The {@link #isDone() isDone} method
* tells when the last step in the computation has been performed. Thus, a
* <code>MultiStepTask</code> has to be executed in a loop that calls the
* {@link #doStep() doStep} method until the {@link #isDone() isDone} method
* returns <code>true</code>.
* <p>The {@link CmdProcessor} makes provisions for executing a
* <code>MultiStepTask</code> asynchronously and retrieving the result of
* the computation (or any exception) via a {@link Future}.</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 interface MultiStepTask
{
/**
* Carries out one step in the computation.
*
* @return The partial result computed by this step.
* @throws Exception If any error occurs.
*/
public Object doStep() throws Exception;
/**
* Tells when the last step in the computation has been performed.
*
* @return <code>true</code> if the last step has been performed,
* <code>false</code> otherwise.
*/
public boolean isDone();
}