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; /** * The auxiliary interface of a Tag, IterationTag or BodyTag tag * handler that wants additional hooks for managing resources. * * <p>This interface provides two new methods: doCatch(Throwable) * and doFinally(). The prototypical invocation is as follows: * * <pre> * h = get a Tag(); // get a tag handler, perhaps from pool * * h.setPageContext(pc); // initialize as desired * h.setParent(null); * h.setFoo("foo"); * * // tag invocation protocol; see Tag.java * try { * doStartTag()... * .... * doEndTag()... * } catch (Throwable t) { * // react to exceptional condition * h.doCatch(t); * } finally { * // restore data invariants and release per-invocation resources * h.doFinally(); * } * * ... other invocations perhaps with some new setters * ... * h.release(); // release long-term resources * </pre> */ public interface TryCatchFinally { /** * Invoked if a Throwable occurs while evaluating the BODY * inside a tag or in any of the following methods: * Tag.doStartTag(), Tag.doEndTag(), * IterationTag.doAfterBody() and BodyTag.doInitBody(). * * <p>This method is not invoked if the Throwable occurs during * one of the setter methods. * * <p>This method may throw an exception (the same or a new one) * that will be propagated further up the nest chain. If an exception * is thrown, doFinally() will be invoked. * * <p>This method is intended to be used to respond to an exceptional * condition. * * @param t The throwable exception navigating through this tag. * @throws Throwable if the exception is to be rethrown further up * the nest chain. */ void doCatch(Throwable t) throws Throwable; /** * Invoked in all cases after doEndTag() for any class implementing * Tag, IterationTag or BodyTag. This method is invoked even if * an exception has occurred in the BODY of the tag, * or in any of the following methods: * Tag.doStartTag(), Tag.doEndTag(), * IterationTag.doAfterBody() and BodyTag.doInitBody(). * * <p>This method is not invoked if the Throwable occurs during * one of the setter methods. * * <p>This method should not throw an Exception. * * <p>This method is intended to maintain per-invocation data * integrity and resource management actions. */ void doFinally(); }