Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 1997-2011 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html * or packager/legal/LICENSE.txt. See the License for the specific * language governing permissions and limitations under the License. * * When distributing the software, include this License Header Notice in each * file and include the License file at packager/legal/LICENSE.txt. * * GPL Classpath Exception: * Oracle designates this particular file as subject to the "Classpath" * exception as provided by Oracle in the GPL Version 2 section of the License * file that accompanied this code. * * Modifications: * If applicable, add the following below the License Header, with the fields * enclosed by brackets [] replaced by your own identifying information: * "Portions Copyright [year] [name of copyright owner]" * * Contributor(s): * If you wish your version of this file to be governed by only the CDDL or * only the GPL Version 2, indicate your decision by adding "[Contributor] * elects to include this software in this distribution under the [CDDL or GPL * Version 2] license." If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. * * * This file incorporates work covered by the following copyright and * permission notice: * * Copyright 2004 The Apache Software Foundation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package javax.servlet.jsp; import javax.servlet.Servlet; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.ServletContext; import javax.servlet.jsp.PageContext; /** * <p> * The JspFactory is an abstract class that defines a number of factory * methods available to a JSP page at runtime for the purposes of creating * instances of various interfaces and classes used to support the JSP * implementation. * <p> * A conformant JSP Engine implementation will, during it's initialization * instantiate an implementation dependent subclass of this class, and make * it globally available for use by JSP implementation classes by registering * the instance created with this class via the * static <code> setDefaultFactory() </code> method. * <p> * The only implementation-dependent classes that can be created from the * factory are: * PageContext, * JspEngineInfo, and * JspApplicationContext. * <p> * With the exception of JspApplicationContext, * JspFactory objects should not be used by JSP application developers. */ public abstract class JspFactory { private static volatile JspFactory deflt = null; /** * Sole constructor. (For invocation by subclass constructors, * typically implicit.) */ public JspFactory() { } /** * <p> * set the default factory for this implementation. It is illegal for * any principal other than the JSP Engine runtime to call this method. * </p> * * @param deflt The default factory implementation */ public static void setDefaultFactory(JspFactory deflt) { JspFactory.deflt = deflt; } /** * Returns the default factory for this implementation. * * @return the default factory for this implementation */ public static JspFactory getDefaultFactory() { return deflt; } /** * <p> * obtains an instance of an implementation dependent * javax.servlet.jsp.PageContext abstract class for the calling Servlet * and currently pending request and response. * </p> * * <p> * This method is typically called early in the processing of the * _jspService() method of a JSP implementation class in order to * obtain a PageContext object for the request being processed. * </p> * <p> * Invoking this method shall result in the PageContext.initialize() * method being invoked. The PageContext returned is properly initialized. * </p> * <p> * All PageContext objects obtained via this method shall be released * by invoking releasePageContext(). * </p> * * @param servlet the requesting servlet * @param request the current request pending on the servlet * @param response the current response pending on the servlet * @param errorPageURL the URL of the error page for the requesting JSP, or null * @param needsSession true if the JSP participates in a session * @param buffer size of buffer in bytes, JspWriter.NO_BUFFER if no buffer, * JspWriter.DEFAULT_BUFFER if implementation default. * @param autoflush should the buffer autoflush to the output stream on buffer * overflow, or throw an IOException? * * @return the page context * * @see javax.servlet.jsp.PageContext */ public abstract PageContext getPageContext(Servlet servlet, ServletRequest request, ServletResponse response, String errorPageURL, boolean needsSession, int buffer, boolean autoflush); /** * <p> * called to release a previously allocated PageContext object. * Results in PageContext.release() being invoked. * This method should be invoked prior to returning from the _jspService() method of a JSP implementation * class. * </p> * * @param pc A PageContext previously obtained by getPageContext() */ public abstract void releasePageContext(PageContext pc); /** * <p> * called to get implementation-specific information on the current JSP engine. * </p> * * @return a JspEngineInfo object describing the current JSP engine */ public abstract JspEngineInfo getEngineInfo(); /** * Obtains the <code>JspApplicationContext</code> instance associated * with the web application for the given <code>ServletContext</code>. * * @param context The <code>ServletContext</code> for the web * application the desired <code>JspApplicationContext</code> is * associated with. * @return The <code>JspApplicationContext</code> associated with the * web application. * @since 2.1 */ public abstract JspApplicationContext getJspApplicationContext(ServletContext context); }