Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 1997-2010 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.tagext; import java.io.IOException; import java.io.Writer; import javax.servlet.jsp.*; /** * Encapsulates a portion of JSP code in an object that * can be invoked as many times as needed. JSP Fragments are defined * using JSP syntax as the body of a tag for an invocation to a SimpleTag * handler, or as the body of a <jsp:attribute> standard action * specifying the value of an attribute that is declared as a fragment, * or to be of type JspFragment in the TLD. * <p> * The definition of the JSP fragment must only contain template * text and JSP action elements. In other words, it must not contain * scriptlets or scriptlet expressions. At translation time, the * container generates an implementation of the JspFragment abstract class * capable of executing the defined fragment. * <p> * A tag handler can invoke the fragment zero or more times, or * pass it along to other tags, before returning. To communicate values * to/from a JSP fragment, tag handlers store/retrieve values in * the JspContext associated with the fragment. * <p> * Note that tag library developers and page authors should not generate * JspFragment implementations manually. * <p> * <i>Implementation Note</i>: It is not necessary to generate a * separate class for each fragment. One possible implementation is * to generate a single helper class for each page that implements * JspFragment. Upon construction, a discriminator can be passed to * select which fragment that instance will execute. * * @since JSP 2.0 */ public abstract class JspFragment { /** * Executes the fragment and directs all output to the given Writer, * or the JspWriter returned by the getOut() method of the JspContext * associated with the fragment if out is null. * * @param out The Writer to output the fragment to, or null if * output should be sent to JspContext.getOut(). * @throws javax.servlet.jsp.JspException Thrown if an error occured * while invoking this fragment. * @throws javax.servlet.jsp.SkipPageException Thrown if the page * that (either directly or indirectly) invoked the tag handler that * invoked this fragment is to cease evaluation. The container * must throw this exception if a Classic Tag Handler returned * Tag.SKIP_PAGE or if a Simple Tag Handler threw SkipPageException. * @throws java.io.IOException If there was an error writing to the * stream. */ public abstract void invoke(Writer out) throws JspException, IOException; /** * Returns the JspContext that is bound to this JspFragment. * * @return The JspContext used by this fragment at invocation time. */ public abstract JspContext getJspContext(); }