/*
* org.openmicroscopy.shoola.env.init.InitializationTask
*
*------------------------------------------------------------------------------
* 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.init;
//Java imports
//Third-party libraries
//Application-internal dependencies
import org.openmicroscopy.shoola.env.Container;
/**
* Declares the interface for configuring and executing an initialization
* task.
* <p>Tasks are encapsulated by objects and treated as commands by the
* {@link Initializer}, which first configures them and then executes them all.
* </p>
* <p>This class factors out a reference to the {@link Container} singleton, as
* this object is needed by all initialization tasks to perform their activity.
* It also factors out a reference to the {@link Initializer} which is needed
* by some tasks.</p>
* <p>Because task objects are created through reflection, every subclass will
* have to provide a public no-parms constructor.</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
*/
abstract class InitializationTask
{
/** Reference to the singleton {@link Container}. */
protected Container container;
/** Reference to the command processor. */
protected Initializer initializer;
/**
* Links this object to the {@link Container}.
* Called by the reflection code in the {@link Initializer} to set
* the reference to the {@link Container} when the object is created.
*
* @param c Reference to the singleton {@link Container}.
*/
void linkContainer(Container c) { container = c; }
/**
* Links this object to the {@link Initializer}.
* Called by the reflection code in the {@link Initializer} to set
* the reference to the {@link Initializer} when the object is created.
*
* @param i Reference to the {@link Initializer}.
*/
void linkInitializer(Initializer i) { initializer = i; }
/**
* Returns the name of this task.
* The returned string should be something meaningful to the user, as
* it will be displayed on the splash screen.
* This method is called after {@link #configure()}, but before
* {@link #execute()}.
*
* @return See above.
*/
abstract String getName();
/**
* Prepare the task for execution.
* This method is called before {@link #execute()}.
*
*/
abstract void configure();
/**
* Carries out the initialization task.
*
* @throws StartupException If an error occurs.
*/
abstract void execute() throws StartupException;
/**
* Rolls back the initialization task.
* This method is typically implemented by those tasks that require
* to be undone if an error occurs during the initialization procedure
* — this allows for the container to exit gracefully. For example,
* the data management service has to release any acquired network
* resources before the program exits.
*/
abstract void rollback();
}