| /* | |
| * Copyright (c) 1997, 1998, 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 javax.swing.plaf; | |
| /** | |
| * This interface is used to mark objects created by ComponentUI delegates. | |
| * The <code>ComponentUI.installUI()</code> and | |
| * <code>ComponentUI.uninstallUI()</code> methods can use this interface | |
| * to decide if a properties value has been overridden. For example, the | |
| * JList cellRenderer property is initialized by BasicListUI.installUI(), | |
| * only if it's initial value is null: | |
| * <pre> | |
| * if (list.getCellRenderer() == null) { | |
| * list.setCellRenderer((ListCellRenderer)(UIManager.get("List.cellRenderer"))); | |
| * } | |
| * </pre> | |
| * At uninstallUI() time we reset the property to null if its value | |
| * is an instance of UIResource: | |
| * <pre> | |
| * if (list.getCellRenderer() instanceof UIResource) { | |
| * list.setCellRenderer(null); | |
| * } | |
| *</pre> | |
| * This pattern applies to all properties except the java.awt.Component | |
| * properties font, foreground, and background. If one of these | |
| * properties isn't initialized, or is explicitly set to null, | |
| * its container provides the value. For this reason the | |
| * <code>"== null"</code> is unreliable when installUI() is called | |
| * to dynamically change a components look and feel. So at installUI() | |
| * time we check to see if the current value is a UIResource: | |
| *<pre> | |
| * if (!(list.getFont() instanceof UIResource)) { | |
| * list.setFont(UIManager.getFont("List.font")); | |
| * } | |
| * </pre> | |
| * | |
| * @see ComponentUI | |
| * @author Hans Muller | |
| * | |
| */ | |
| public interface UIResource { | |
| } |