001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package javax.servlet.jsp; 018 019 import javax.servlet.Servlet; 020 import javax.servlet.ServletContext; 021 import javax.servlet.ServletRequest; 022 import javax.servlet.ServletResponse; 023 import javax.servlet.jsp.PageContext; 024 025 /** 026 * <p> 027 * The JspFactory is an abstract class that defines a number of factory 028 * methods available to a JSP page at runtime for the purposes of creating 029 * instances of various interfaces and classes used to support the JSP 030 * implementation. 031 * <p> 032 * A conformant JSP Engine implementation will, during it's initialization 033 * instantiate an implementation dependent subclass of this class, and make 034 * it globally available for use by JSP implementation classes by registering 035 * the instance created with this class via the 036 * static <code> setDefaultFactory() </code> method. 037 * <p> 038 * The PageContext and the JspEngineInfo classes are the only implementation-dependent 039 * classes that can be created from the factory. 040 * <p> 041 * JspFactory objects should not be used by JSP page authors. 042 */ 043 044 public abstract class JspFactory { 045 046 private static JspFactory deflt = null; 047 048 /** 049 * Sole constructor. (For invocation by subclass constructors, 050 * typically implicit.) 051 */ 052 public JspFactory() { 053 } 054 055 /** 056 * <p> 057 * set the default factory for this implementation. It is illegal for 058 * any principal other than the JSP Engine runtime to call this method. 059 * </p> 060 * 061 * @param deflt The default factory implementation 062 */ 063 064 public static synchronized void setDefaultFactory(JspFactory deflt) { 065 JspFactory.deflt = deflt; 066 } 067 068 /** 069 * Returns the default factory for this implementation. 070 * 071 * @return the default factory for this implementation 072 */ 073 074 public static synchronized JspFactory getDefaultFactory() { 075 return deflt; 076 } 077 078 /** 079 * <p> 080 * obtains an instance of an implementation dependent 081 * javax.servlet.jsp.PageContext abstract class for the calling Servlet 082 * and currently pending request and response. 083 * </p> 084 * 085 * <p> 086 * This method is typically called early in the processing of the 087 * _jspService() method of a JSP implementation class in order to 088 * obtain a PageContext object for the request being processed. 089 * </p> 090 * <p> 091 * Invoking this method shall result in the PageContext.initialize() 092 * method being invoked. The PageContext returned is properly initialized. 093 * </p> 094 * <p> 095 * All PageContext objects obtained via this method shall be released 096 * by invoking releasePageContext(). 097 * </p> 098 * 099 * @param servlet the requesting servlet 100 * @param request the current request pending on the servlet 101 * @param response the current response pending on the servlet 102 * @param errorPageURL the URL of the error page for the requesting JSP, or null 103 * @param needsSession true if the JSP participates in a session 104 * @param buffer size of buffer in bytes, PageContext.NO_BUFFER if no buffer, 105 * PageContext.DEFAULT_BUFFER if implementation default. 106 * @param autoflush should the buffer autoflush to the output stream on buffer 107 * overflow, or throw an IOException? 108 * 109 * @return the page context 110 * 111 * @see javax.servlet.jsp.PageContext 112 */ 113 114 public abstract PageContext getPageContext(Servlet servlet, 115 ServletRequest request, 116 ServletResponse response, 117 String errorPageURL, 118 boolean needsSession, 119 int buffer, 120 boolean autoflush); 121 122 /** 123 * <p> 124 * called to release a previously allocated PageContext object. 125 * Results in PageContext.release() being invoked. 126 * This method should be invoked prior to returning from the _jspService() method of a JSP implementation 127 * class. 128 * </p> 129 * 130 * @param pc A PageContext previously obtained by getPageContext() 131 */ 132 133 public abstract void releasePageContext(PageContext pc); 134 135 /** 136 * <p> 137 * called to get implementation-specific information on the current JSP engine. 138 * </p> 139 * 140 * @return a JspEngineInfo object describing the current JSP engine 141 */ 142 143 public abstract JspEngineInfo getEngineInfo(); 144 145 /** 146 * <p> 147 * Obtain the <code>JspApplicationContext</code> instance that was associated 148 * within the passed <code>ServletContext</code> for this web application. 149 * </p> 150 * 151 * @param context the current web application's <code>ServletContext</code> 152 * @return <code>JspApplicationContext</code> instance 153 * @since 2.1 154 */ 155 public abstract JspApplicationContext getJspApplicationContext(ServletContext context); 156 }