| /******************************************************************************* |
| * Copyright (C) 2007 The University of Manchester |
| * |
| * Modifications to the initial code base are copyright of their |
| * respective authors, or their employers as appropriate. |
| * |
| * This program 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 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 |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
| ******************************************************************************/ |
| package net.sf.taverna.t2.lang.observer; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.log4j.Logger; |
| |
| /** |
| * Send notifications to registered observers about changes to models |
| * |
| * @author Ian Dunlop |
| * @author Stian Soiland |
| * |
| * @param <Message> |
| */ |
| public class MultiCaster<Message> implements Observable<Message> { |
| |
| private static Logger logger = Logger.getLogger(MultiCaster.class); |
| |
| private Observable<Message> observable; |
| |
| protected List<Observer<Message>> observers = new ArrayList<Observer<Message>>(); |
| |
| /** |
| * Set the {@link #observable} ie. the class that changes are happening to |
| * and it's Message for this {@link MultiCaster} |
| * |
| * @param observable |
| */ |
| public MultiCaster(Observable<Message> observable) { |
| this.observable = observable; |
| } |
| |
| /** |
| * Tell all the registered observers about the change to the model |
| * |
| * @param message |
| */ |
| @SuppressWarnings("unchecked") |
| public void notify(Message message) { |
| // Use a copy that can be iterated even if register/remove is called |
| for (Observer<Message> observer : getObservers()) { |
| try { |
| observer.notify(observable, message); |
| } catch (Exception ex) { |
| logger.warn("Could not notify " + observer, ex); |
| } |
| } |
| } |
| |
| /** |
| * Register an observer ie. someone who wants informed about changes |
| */ |
| public synchronized void addObserver(Observer<Message> observer) { |
| observers.add(observer); |
| } |
| |
| /** |
| * Remove the observer and no longer send out any notifications about it |
| */ |
| public synchronized void removeObserver(Observer<Message> observer) { |
| observers.remove(observer); |
| } |
| |
| /** |
| * A list of all the classes currently registered with this |
| * {@link MultiCaster} |
| */ |
| public synchronized List<Observer<Message>> getObservers() { |
| return new ArrayList<Observer<Message>>(observers); |
| } |
| |
| } |