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, ServletResponse response,
116: String errorPageURL, boolean needsSession, int buffer,
117: boolean autoflush);
118:
119: /**
120: * <p>
121: * called to release a previously allocated PageContext object.
122: * Results in PageContext.release() being invoked.
123: * This method should be invoked prior to returning from the _jspService() method of a JSP implementation
124: * class.
125: * </p>
126: *
127: * @param pc A PageContext previously obtained by getPageContext()
128: */
129:
130: public abstract void releasePageContext(PageContext pc);
131:
132: /**
133: * <p>
134: * called to get implementation-specific information on the current JSP engine.
135: * </p>
136: *
137: * @return a JspEngineInfo object describing the current JSP engine
138: */
139:
140: public abstract JspEngineInfo getEngineInfo();
141:
142: /**
143: * <p>
144: * Obtain the <code>JspApplicationContext</code> instance that was associated
145: * within the passed <code>ServletContext</code> for this web application.
146: * </p>
147: *
148: * @param context the current web application's <code>ServletContext</code>
149: * @return <code>JspApplicationContext</code> instance
150: * @since 2.1
151: */
152: public abstract JspApplicationContext getJspApplicationContext(
153: ServletContext context);
154: }
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