001package org.apache.turbine.modules.layouts;
002
003
004/*
005 * Licensed to the Apache Software Foundation (ASF) under one
006 * or more contributor license agreements.  See the NOTICE file
007 * distributed with this work for additional information
008 * regarding copyright ownership.  The ASF licenses this file
009 * to you under the Apache License, Version 2.0 (the
010 * "License"); you may not use this file except in compliance
011 * with the License.  You may obtain a copy of the License at
012 *
013 *   http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing,
016 * software distributed under the License is distributed on an
017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
018 * KIND, either express or implied.  See the License for the
019 * specific language governing permissions and limitations
020 * under the License.
021 */
022
023
024import org.apache.commons.lang3.StringUtils;
025import org.apache.turbine.TurbineConstants;
026import org.apache.turbine.annotation.TurbineLoader;
027import org.apache.turbine.modules.Screen;
028import org.apache.turbine.modules.ScreenLoader;
029import org.apache.turbine.pipeline.PipelineData;
030import org.apache.turbine.util.template.TemplateNavigation;
031import org.apache.velocity.context.Context;
032
033/**
034 * This Layout module allows Velocity templates to be used as layouts.
035 * Since dynamic content is supposed to be primarily located in
036 * screens and navigations there should be relatively few reasons to
037 * subclass this Layout.
038 *
039 * To get the same functionality as with VelocityECSLayout, you can use two
040 * supplied VelocityMacros, TurbineHtmlHead and TurbineHtmlBodyAttributes
041 * in your templates. These are used to put HtmlPageAttributes into a page
042 * before rendering.
043 *
044 * Use these macros should be used in the Layout template like this:
045 *
046 * ... set things like style sheets, scripts here.
047 * <html>
048 * #TurbineHtmlHead()
049 * <body #TurbineHtmlBodyAttributes() >
050 *  .... your body information
051 * </body>
052 * </html>
053 *
054 * As the layout template is rendered _after_ the screen template, you
055 * can of course, add information to the $page tool in your screen template.
056 * This will be added correctly to the <head>...</head> and
057 * <body> tags.
058 *
059 * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
060 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
061 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
062 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
063 * @version $Id$
064 */
065public class VelocityOnlyLayout extends VelocityLayout
066{
067    /** Injected loader instance */
068    @TurbineLoader( Screen.class )
069    private ScreenLoader screenLoader;
070
071    /**
072     * @see org.apache.turbine.modules.layouts.VelocityLayout#populateContext(org.apache.turbine.pipeline.PipelineData, org.apache.velocity.context.Context)
073     */
074    @Override
075    protected void populateContext(PipelineData pipelineData, Context context) throws Exception
076    {
077        String screenName = pipelineData.getRunData().getScreen();
078
079        log.debug("Loading Screen {}", screenName);
080
081        // First, generate the screen and put it in the context so
082        // we can grab it the layout template.
083        String results = screenLoader.eval(pipelineData, screenName);
084        String returnValue = StringUtils.defaultIfEmpty(results, StringUtils.EMPTY);
085
086        // variable for the screen in the layout template
087        context.put(TurbineConstants.SCREEN_PLACEHOLDER, returnValue);
088
089        // variable to reference the navigation screen in the layout template
090        context.put(TurbineConstants.NAVIGATION_PLACEHOLDER,
091                    new TemplateNavigation(pipelineData));
092    }
093}