--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/swing/plaf/UIResource.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,67 @@
+/*
+ * Copyright 1997-1998 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.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 {
+}