/* * Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javafx.beans.binding; import javafx.beans.value.ObservableValue; import javafx.collections.ObservableList; /** * A {@code Binding} calculates a value that depends on one or more sources. The * sources are usually called the dependency of a binding. A binding observes * its dependencies for changes and updates its value automatically. *
* While a dependency of a binding can be anything, it is almost always an * implementation of {@link javafx.beans.value.ObservableValue}. {@code Binding} * implements {@code ObservableValue} allowing to use it in another binding. * With that one can assemble very complex bindings from simple bindings. *
* All bindings in the JavaFX runtime are calculated lazily. That means, if * a dependency changes, the result of a binding is not immediately * recalculated, but it is marked as invalid. Next time the value of an invalid * binding is requested, it is recalculated. *
* It is recommended to use one of the base classes defined in this package
* (e.g. {@link DoubleBinding}) to define a custom binding, because these
* classes already provide most of the needed functionality. See
* {@link DoubleBinding} for an example.
*
* @param
* Because this method should not be used in production code, it is
* recommended to implement this functionality as sparse as possible. For
* example if the dependencies do not change, each call can generate a new
* {@code ObservableList}, avoiding the necessity to store the result.
*
* @return an unmodifiable {@code} ObservableList of the dependencies
*/
ObservableList> getDependencies();
/**
* Signals to the {@code Binding} that it will not be used anymore and any
* references can be removed. A call of this method usually results in the
* binding stopping to observe its dependencies by unregistering its
* listener(s). The implementation is optional.
*
* All bindings in our implementation use instances of
* {@link javafx.beans.WeakInvalidationListener}, which means usually
* a binding does not need to be disposed. But if you plan to use your
* application in environments that do not support {@code WeakReferences}
* you have to dispose unused {@code Bindings} to avoid memory leaks.
*/
void dispose();
}