TaskObserver.java
/*
* Copyright (C) 2016 essobedo.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package com.github.essobedo.appma.task;
import java.util.Observable;
import java.util.Observer;
/**
* Defines the {@link Observer} of a {@link Task}.
*
* @author Nicolas Filotto (nicolas.filotto@gmail.com)
* @version $Id$
* @since 1.0
*/
public interface TaskObserver extends Observer {
@Override
default void update(final Observable observable, final Object object) {
final Task<?> task;
if (observable instanceof Task) {
task = (Task<?>) observable;
} else {
throw new IllegalArgumentException("A task was expected");
}
final Task.Event event;
if (object instanceof Task.Event) {
event = (Task.Event) object;
} else {
throw new IllegalArgumentException("A task event was expected");
}
switch (event) {
case PROGRESS:
updateProgress(task.getWorkDone(), task.getMax());
break;
case MESSAGE:
updateMessage(task.getMessage());
break;
case CANCEL:
cancel();
break;
default:
throw new IllegalArgumentException("Unknown event");
}
}
/**
* Notifies that the current progress of the task has changed.
* @param done the work already done.
* @param max the maximum work to be done.
*/
void updateProgress(int done, int max);
/**
* Notifies that the status of the task has changed.
* @param message the status of the task.
*/
void updateMessage(String message);
/**
* Notifies that the task has been canceled.
*/
void cancel();
}