1 /* 2 * Copyright (c) 2009, 2016, 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.scene.layout; 27 28 import java.util.Iterator; 29 30 import javafx.scene.Parent; 31 32 import com.sun.javafx.util.WeakReferenceQueue; 33 34 /** 35 * The base class for defining node-specific layout constraints. Region 36 * classes may create extensions of this class if they need to define their own 37 * set of layout constraints. 38 * 39 * @since JavaFX 2.0 40 */ 41 public abstract class ConstraintsBase { 42 43 /** 44 * If set as max value indicates that the pref value should be used as the max. 45 * This allows an application to constrain a resizable node's size, which normally 46 * has an unlimited max value, to its preferred size. 47 */ 48 public static final double CONSTRAIN_TO_PREF = Double.NEGATIVE_INFINITY; 49 50 private WeakReferenceQueue nodes = new WeakReferenceQueue(); 51 52 ConstraintsBase() { 53 } 54 55 void add(Parent node) { 56 nodes.add(node); 57 } 58 59 void remove(Parent node) { 60 nodes.remove(node); 61 } 62 63 /** 64 * Calls requestLayout on layout parent associated with this constraint object. 65 */ 66 protected void requestLayout() { 67 Iterator<Parent> nodeIter = nodes.iterator(); 68 69 while (nodeIter.hasNext()) { 70 nodeIter.next().requestLayout(); 71 } 72 } 73 }