/** * Copyright (C) 2001-2017 by RapidMiner and the contributors * * Complete list of developers available at our web site: * * http://rapidminer.com * * This program is free software: you can redistribute it and/or modify it under the terms of the * GNU Affero General Public License as published by the Free Software Foundation, either version 3 * 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 * Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License along with this program. * If not, see http://www.gnu.org/licenses/. */ package com.rapidminer.tools; import java.util.NoSuchElementException; /** * Reimplementation of the Java 1.0 Observer pattern. It has some advantages: * <ol> * <li>Separation of interface and implementation</li> * <li>Generics argument to the update method</li> * <li>and foremost: The update method can be called on the Event Dispatch Thread (EDT) if this is * desired. If you don't know, what the EDT is, read the Java docs on Swing and synchronization and * use EDT if you register an observer that updates Swing GUI components.</li> * <li>synchronization (Sun's implementation may be synchronized, too, but it is not documented)</li> * <li>defined exception handling.</li> * </ol> * * @author Simon Fischer * */ public interface Observable<A> { /** * Adds an observer that will be notified on the EDT if onEDT is true. * * @throws a * NPE if observer is null. */ public void addObserver(Observer<A> observer, boolean onEDT); /** * Removes an observer from this observable. * * @throws NoSuchElementException * if observer is not registered with this Observable. */ public void removeObserver(Observer<A> observer); /** * Same as {@link #addObserver(Observer, boolean), but adds this observer as the first in the * list. */ void addObserverAsFirst(Observer<A> observer, boolean onEDT); }