1 /* 2 * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javafx.beans.value; 27 28 /** 29 * A {@code ChangeListener} is notified whenever the value of an 30 * {@link ObservableValue} changes. It can be registered and unregistered with 31 * {@link ObservableValue#addListener(ChangeListener)} respectively 32 * {@link ObservableValue#removeListener(ChangeListener)} 33 * <p> 34 * For an in-depth explanation of change events and how they differ from 35 * invalidation events, see the documentation of {@code ObservableValue}. 36 * <p> 37 * The same instance of {@code ChangeListener} can be registered to listen to 38 * multiple {@code ObservableValues}. 39 * 40 * @see ObservableValue 41 * 42 * 43 * @since JavaFX 2.0 44 */ 45 @FunctionalInterface 46 public interface ChangeListener<T> { 47 48 /** 49 * This method needs to be provided by an implementation of 50 * {@code ChangeListener}. It is called if the value of an 51 * {@link ObservableValue} changes. 52 * <p> 53 * In general, it is considered bad practice to modify the observed value in 54 * this method. 55 * 56 * @param observable 57 * The {@code ObservableValue} which value changed 58 * @param oldValue 59 * The old value 60 * @param newValue 61 * The new value 62 */ 63 void changed(ObservableValue<? extends T> observable, T oldValue, T newValue); 64 }