Java tutorial
/* * $Header: /home/cvs/jakarta-tomcat-catalina/catalina/src/share/org/apache/catalina/core/ApplicationContextFacade.java,v 1.8 2003/09/02 21:22:04 remm Exp $ * $Revision: 1.8 $ * $Date: 2003/09/02 21:22:04 $ * * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * [Additional notices, if required by prior licensing conditions] * */ package org.apache.catalina.core; import java.io.InputStream; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.net.MalformedURLException; import java.net.URL; import java.security.AccessController; import java.security.PrivilegedActionException; import java.security.PrivilegedExceptionAction; import java.util.Enumeration; import java.util.HashMap; import java.util.Set; import javax.servlet.RequestDispatcher; import javax.servlet.Servlet; import javax.servlet.ServletContext; import javax.servlet.ServletException; /** * Facade object which masks the internal <code>ApplicationContext</code> * object from the web application. * * @author Remy Maucherat * @author Jean-Francois Arcand * @version $Revision: 1.8 $ $Date: 2003/09/02 21:22:04 $ */ public final class ApplicationContextFacade implements ServletContext { // ---------------------------------------------------------- Attributes /** * Cache Class object used for reflection. */ private HashMap classCache; /** * Cache method object. */ private HashMap objectCache; private static org.apache.commons.logging.Log sysLog = org.apache.commons.logging.LogFactory .getLog(ApplicationContextFacade.class); // ----------------------------------------------------------- Constructors /** * Construct a new instance of this class, associated with the specified * Context instance. * * @param context The associated Context instance */ public ApplicationContextFacade(ApplicationContext context) { super(); this.context = context; classCache = new HashMap(); objectCache = new HashMap(); initClassCache(); } private void initClassCache() { Class[] clazz = new Class[] { String.class }; classCache.put("getContext", clazz); classCache.put("getMimeType", clazz); classCache.put("getResourcePaths", clazz); classCache.put("getResource", clazz); classCache.put("getResourceAsStream", clazz); classCache.put("getRequestDispatcher", clazz); classCache.put("getNamedDispatcher", clazz); classCache.put("getServlet", clazz); classCache.put("getInitParameter", clazz); classCache.put("setAttribute", new Class[] { String.class, Object.class }); classCache.put("removeAttribute", clazz); classCache.put("getRealPath", clazz); classCache.put("getAttribute", clazz); classCache.put("log", clazz); } // ----------------------------------------------------- Instance Variables /** * Wrapped application context. */ private ApplicationContext context = null; // ------------------------------------------------- ServletContext Methods public ServletContext getContext(String uripath) { ServletContext theContext = null; if (System.getSecurityManager() != null) { theContext = (ServletContext) doPrivileged("getContext", new Object[] { uripath }); } else { theContext = context.getContext(uripath); } if ((theContext != null) && (theContext instanceof ApplicationContext)) { theContext = ((ApplicationContext) theContext).getFacade(); } return (theContext); } public int getMajorVersion() { return context.getMajorVersion(); } public int getMinorVersion() { return context.getMinorVersion(); } public String getMimeType(String file) { if (System.getSecurityManager() != null) { return (String) doPrivileged("getMimeType", new Object[] { file }); } else { return context.getMimeType(file); } } public Set getResourcePaths(String path) { if (System.getSecurityManager() != null) { return (Set) doPrivileged("getResourcePaths", new Object[] { path }); } else { return context.getResourcePaths(path); } } public URL getResource(String path) throws MalformedURLException { if (System.getSecurityManager() != null) { try { return (URL) invokeMethod(context, "getResource", new Object[] { path }); } catch (Throwable t) { if (t instanceof MalformedURLException) { throw (MalformedURLException) t; } return null; } } else { return context.getResource(path); } } public InputStream getResourceAsStream(String path) { if (System.getSecurityManager() != null) { return (InputStream) doPrivileged("getResourceAsStream", new Object[] { path }); } else { return context.getResourceAsStream(path); } } public RequestDispatcher getRequestDispatcher(final String path) { if (System.getSecurityManager() != null) { return (RequestDispatcher) doPrivileged("getRequestDispatcher", new Object[] { path }); } else { return context.getRequestDispatcher(path); } } public RequestDispatcher getNamedDispatcher(String name) { if (System.getSecurityManager() != null) { return (RequestDispatcher) doPrivileged("getNamedDispatcher", new Object[] { name }); } else { return context.getNamedDispatcher(name); } } public Servlet getServlet(String name) throws ServletException { if (System.getSecurityManager() != null) { try { return (Servlet) invokeMethod(context, "getServlet", new Object[] { name }); } catch (Throwable t) { if (t instanceof ServletException) { throw (ServletException) t; } return null; } } else { return context.getServlet(name); } } public Enumeration getServlets() { if (System.getSecurityManager() != null) { return (Enumeration) doPrivileged("getServlets", null); } else { return context.getServlets(); } } public Enumeration getServletNames() { if (System.getSecurityManager() != null) { return (Enumeration) doPrivileged("getServletNames", null); } else { return context.getServletNames(); } } public void log(String msg) { if (System.getSecurityManager() != null) { doPrivileged("log", new Object[] { msg }); } else { context.log(msg); } } public void log(Exception exception, String msg) { if (System.getSecurityManager() != null) { doPrivileged("log", new Class[] { Exception.class, String.class }, new Object[] { exception, msg }); } else { context.log(exception, msg); } } public void log(String message, Throwable throwable) { if (System.getSecurityManager() != null) { doPrivileged("log", new Class[] { String.class, Throwable.class }, new Object[] { message, throwable }); } else { context.log(message, throwable); } } public String getRealPath(String path) { if (System.getSecurityManager() != null) { return (String) doPrivileged("getRealPath", new Object[] { path }); } else { return context.getRealPath(path); } } public String getServerInfo() { if (System.getSecurityManager() != null) { return (String) doPrivileged("getServerInfo", null); } else { return context.getServerInfo(); } } public String getInitParameter(String name) { if (System.getSecurityManager() != null) { return (String) doPrivileged("getInitParameter", new Object[] { name }); } else { return context.getInitParameter(name); } } public Enumeration getInitParameterNames() { if (System.getSecurityManager() != null) { return (Enumeration) doPrivileged("getInitParameterNames", null); } else { return context.getInitParameterNames(); } } public Object getAttribute(String name) { if (System.getSecurityManager() != null) { return doPrivileged("getAttribute", new Object[] { name }); } else { return context.getAttribute(name); } } public Enumeration getAttributeNames() { if (System.getSecurityManager() != null) { return (Enumeration) doPrivileged("getAttributeNames", null); } else { return context.getAttributeNames(); } } public void setAttribute(String name, Object object) { if (System.getSecurityManager() != null) { doPrivileged("setAttribute", new Object[] { name, object }); } else { context.setAttribute(name, object); } } public void removeAttribute(String name) { if (System.getSecurityManager() != null) { doPrivileged("removeAttribute", new Object[] { name }); } else { context.removeAttribute(name); } } public String getServletContextName() { if (System.getSecurityManager() != null) { return (String) doPrivileged("getServletContextName", null); } else { return context.getServletContextName(); } } /** * Use reflection to invoke the requested method. Cache the method object * to speed up the process * @param appContext The AppliationContext object on which the method * will be invoked * @param methodName The method to call. * @param params The arguments passed to the called method. */ private Object doPrivileged(ApplicationContext appContext, final String methodName, final Object[] params) { try { return invokeMethod(appContext, methodName, params); } catch (Throwable t) { throw new RuntimeException(t.getMessage()); } } /** * Use reflection to invoke the requested method. Cache the method object * to speed up the process * will be invoked * @param methodName The method to call. * @param params The arguments passed to the called method. */ private Object doPrivileged(final String methodName, final Object[] params) { try { return invokeMethod(context, methodName, params); } catch (Throwable t) { throw new RuntimeException(t.getMessage()); } } /** * Use reflection to invoke the requested method. Cache the method object * to speed up the process * @param appContext The AppliationContext object on which the method * will be invoked * @param methodName The method to call. * @param params The arguments passed to the called method. */ private Object invokeMethod(ApplicationContext appContext, final String methodName, final Object[] params) throws Throwable { try { Method method = (Method) objectCache.get(methodName); if (method == null) { method = appContext.getClass().getMethod(methodName, (Class[]) classCache.get(methodName)); objectCache.put(methodName, method); } return executeMethod(method, appContext, params); } catch (Exception ex) { handleException(ex, methodName); return null; } } /** * Use reflection to invoke the requested method. Cache the method object * to speed up the process * @param appContext The AppliationContext object on which the method * will be invoked * @param methodName The method to call. * @param params The arguments passed to the called method. */ private Object doPrivileged(final String methodName, final Class[] clazz, final Object[] params) { try { Method method = context.getClass().getMethod(methodName, (Class[]) clazz); return executeMethod(method, context, params); } catch (Exception ex) { try { handleException(ex, methodName); } catch (Throwable t) { throw new RuntimeException(t.getMessage()); } return null; } } /** * Executes the method of the specified <code>ApplicationContext</code> * @param method The method object to be invoked. * @param context The AppliationContext object on which the method * will be invoked * @param params The arguments passed to the called method. */ private Object executeMethod(final Method method, final ApplicationContext context, final Object[] params) throws PrivilegedActionException, IllegalAccessException, InvocationTargetException { if (System.getSecurityManager() != null) { return AccessController.doPrivileged(new PrivilegedExceptionAction() { public Object run() throws IllegalAccessException, InvocationTargetException { return method.invoke(context, params); } }); } else { return method.invoke(context, params); } } /** * Throw the real exception. * @param ex The current exception */ private void handleException(Exception ex, String methodName) throws Throwable { Throwable realException; if (sysLog.isDebugEnabled()) { sysLog.debug("ApplicationContextFacade." + methodName, ex); } if (ex instanceof PrivilegedActionException) { ex = ((PrivilegedActionException) ex).getException(); } if (ex instanceof InvocationTargetException) { realException = ((InvocationTargetException) ex).getTargetException(); } else { realException = ex; } throw realException; } }