| /* CallbackUtil.java -- Callback related utilities |
| Copyright (C) 2006 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.classpath.tools.common; |
| |
| import gnu.javax.security.auth.callback.ConsoleCallbackHandler; |
| |
| import java.security.Provider; |
| import java.security.Security; |
| import java.util.logging.Logger; |
| |
| import javax.security.auth.callback.CallbackHandler; |
| |
| /** |
| * A <i>Helper</i> class containing general purpose utlity methods dealing with |
| * callback handlers and their <i>Security Provider</i>. |
| */ |
| public abstract class CallbackUtil |
| { |
| private static final Logger log = Logger.getLogger(CallbackUtil.class.getName()); |
| |
| // default 0-arguments constructor |
| |
| // Class methods |
| // -------------------------------------------------------------------------- |
| |
| /** |
| * Return an implementation of the {@link CallbackHandler}, from any |
| * {@link Provider}, capable of handling callbacks through the <i>console</i>; |
| * i.e. <code>System.in</code> and <code>System.out</code>. |
| * <p> |
| * If no <i>Security Provider</i> for this type of callback was found, this |
| * method returns the default GNU implementation. |
| * |
| * @return a console {@link CallbackHandler} implementation. |
| */ |
| public static final CallbackHandler getConsoleHandler() |
| { |
| CallbackHandler result = getHandler("Console"); |
| if (result == null) |
| { |
| log.fine("No console callback handler found. Will use ours"); |
| result = new ConsoleCallbackHandler(); |
| } |
| return result; |
| } |
| |
| /** |
| * Return a {@link CallbackHandler}, of a designated type, for interacting |
| * with the user. |
| * <p> |
| * This method first finds all currently installed <i>Security Providers</i> |
| * capable of providing such service and then in turn attempts to instantiate |
| * the handler from those providers. As soon as one provider returns a non- |
| * null instance of the callback handler, the search stops and that instance |
| * is returned. |
| * |
| * @return a {@link CallbackHandler} of the designated type, or |
| * <code>null</code> if no provider was found for theis type of |
| * callback. |
| */ |
| private static final CallbackHandler getHandler(String handlerType) |
| { |
| log.entering(CallbackUtil.class.getName(), "getHandler", handlerType); |
| |
| CallbackHandler result = null; |
| String service = "CallbackHandler." + handlerType; |
| Provider[] providers = Security.getProviders(service); |
| if (providers != null) |
| for (int i = 0; i < providers.length; i++) |
| { |
| Provider p = providers[i]; |
| String className = p.getProperty(service); |
| if (className != null) |
| try |
| { |
| result = (CallbackHandler) Class.forName(className.trim()).newInstance(); |
| } |
| catch (InstantiationException x) |
| { |
| log.fine("InstantiationException while creating [" |
| + className + "] from provider [" + p.getName() |
| + "]. Ignore"); |
| } |
| catch (IllegalAccessException x) |
| { |
| log.fine("IllegalAccessException while creating [" |
| + className + "] from provider [" + p.getName() |
| + "]. Ignore"); |
| } |
| catch (ClassNotFoundException x) |
| { |
| log.fine("ClassNotFoundException while creating [" |
| + className + "] from provider [" + p.getName() |
| + "]. Ignore"); |
| } |
| |
| if (result != null) |
| { |
| |
| log.fine("Will use [" + result.getClass().getName() |
| + "] from [" + p.getName() + "]"); |
| break; |
| } |
| } |
| |
| log.exiting(CallbackUtil.class.getName(), "getHandler", result); |
| return result; |
| } |
| } |