Исходный код

001/*
002 * Copyright (c) 2009, 2013, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.  Oracle designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Oracle in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
022 * or visit www.oracle.com if you need additional information or have any
023 * questions.
024 */
025
026package javafx.scene.layout;
027
028import java.util.Iterator;
029
030import javafx.scene.Node;
031import javafx.scene.Parent;
032
033import com.sun.javafx.WeakReferenceQueue;
034
035/**
036 * The base class for defining node-specific layout constraints.  Region
037 * classes may create extensions of this class if they need to define their own
038 * set of layout constraints.
039 *
040 */
041public abstract class ConstraintsBase {
042
043    /**
044     * If set as max value indicates that the pref value should be used as the max.
045     * This allows an application to constrain a resizable node's size, which normally
046     * has an unlimited max value, to its preferred size.
047     */
048    public static final double CONSTRAIN_TO_PREF = Double.NEGATIVE_INFINITY;
049
050     WeakReferenceQueue impl_nodes = new WeakReferenceQueue();
051     
052     ConstraintsBase() {
053     }
054
055     void add(Node node) {
056         impl_nodes.add(node);
057     }
058
059    void remove(Node node) {
060        impl_nodes.remove(node);
061    }
062
063     /**
064      * Calls requestLayout on layout parent associated with this constraint object.
065      */
066     protected void requestLayout() {
067        Iterator<Node> nodeIter = impl_nodes.iterator();
068        while (nodeIter.hasNext()) {
069            Parent p = nodeIter.next().getParent();
070            if (p != null) {
071                p.requestLayout();
072            }
073        }
074    }
075}