/* * Copyright (c) 1999, 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 sun.awt; /**  * The AWTSecurityManager class provides the ability to secondarily  * index AppContext objects through SecurityManager extensions.  * As noted in AppContext.java, AppContexts are primarily indexed by  * ThreadGroup.  In the case where the ThreadGroup doesn't provide  * enough information to determine AppContext (e.g. system threads),  * if a SecurityManager is installed which derives from  * AWTSecurityManager, the AWTSecurityManager's getAppContext()  * method is called to determine the AppContext.  *  * A typical example of the use of this class is where an applet  * is called by a system thread, yet the system AppContext is  * inappropriate, because applet code is currently executing.  * In this case, the getAppContext() method can walk the call stack  * to determine the applet code being executed and return the applet's  * AppContext object.  *  * @author  Fred Ecks  */public class AWTSecurityManager extends SecurityManager {     /**      * Get the AppContext corresponding to the current context.      * The default implementation returns null, but this method      * may be overridden by various SecurityManagers      * (e.g. AppletSecurity) to index AppContext objects by the      * calling context.      *      * @return  the AppContext corresponding to the current context.      * @see     sun.awt.AppContext      * @see     java.lang.SecurityManager      * @since   JDK1.2.1      */    public AppContext getAppContext() {        return null; // Default implementation returns null    } } /* class AWTSecurityManager */