awtsecuritymanager.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 67 行

/*
 * @(#)AWTSecurityManager.java	1.12 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program 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. 
 * 
 * This program 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 at /legal/license.txt). 
 * 
 * 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 or visit www.sun.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
 * @version 1.8 08/19/02
 */
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 */