001package org.apache.turbine.modules.actions;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.apache.turbine.modules.screens.TemplateScreen;
023import org.apache.turbine.pipeline.PipelineData;
024import org.apache.turbine.util.velocity.VelocityActionEvent;
025import org.apache.velocity.context.Context;
026
027/**
028 * This class provides a convenience methods for Velocity Actions to use. Since
029 * this class is abstract, it should only be extended and not used directly.
030 *
031 * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
032 * @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
033 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
034 * @version $Id$
035 */
036public abstract class VelocityAction extends VelocityActionEvent
037{
038    /**
039     * Initialize the module.
040     *
041     * @throws Exception a generic exception.
042     */
043    @Override
044    public void initialize() throws Exception
045    {
046        initialized = true;
047    }
048
049    /**
050     * You SHOULD override this method and implement it in your action.
051     *
052     * @param pipelineData Turbine information.
053     * @param context Context for web pages.
054     * @throws Exception a generic exception.
055     */
056    public abstract void doPerform(PipelineData pipelineData, Context context)
057            throws Exception;
058
059    /**
060     * Sets up the context and then calls super.perform(); thus, subclasses
061     * don't have to worry about getting a context themselves! If a subclass
062     * throws an exception then depending on whether
063     * action.event.bubbleexception is true, then it bubbles it farther up, or
064     * traps it there.
065     *
066     * @param pipelineData Turbine information.
067     * @throws Exception a generic exception.
068     */
069    @Override
070    public void perform(PipelineData pipelineData) throws Exception
071    {
072        try
073        {
074            super.perform(pipelineData);
075        }
076        catch (Exception e)
077        {
078            if (bubbleUpException)
079            {
080                throw e;
081            }
082        }
083    }
084
085    /**
086     * This method is used when you want to short circuit an Action and change
087     * the template that will be executed next.
088     *
089     * @param pipelineData Turbine information.
090     * @param template The template that will be executed next.
091     */
092    public void setTemplate(PipelineData pipelineData, String template)
093    {
094        TemplateScreen.setTemplate(pipelineData, template);
095    }
096}