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Java > Open Source Codes > org > apache > turbine > modules > layouts > VelocityDirectLayout


1 package org.apache.turbine.modules.layouts;
2
3 /*
4  * Copyright 2001-2004 The Apache Software Foundation.
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License")
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 import org.apache.commons.logging.Log;
20 import org.apache.commons.logging.LogFactory;
21
22 import org.apache.turbine.TurbineConstants;
23 import org.apache.turbine.modules.Layout;
24 import org.apache.turbine.services.velocity.TurbineVelocity;
25 import org.apache.turbine.util.RunData;
26 import org.apache.turbine.util.template.TemplateNavigation;
27 import org.apache.turbine.util.template.TemplateScreen;
28
29 import org.apache.velocity.context.Context;
30
31 /**
32  * This Layout module allows Velocity templates
33  * to be used as layouts. It will stream directly the output of
34  * the layout and navigation templates to the output writer without
35  * using a screen. Use this if you have a large page to output
36  * and won't buffer it in the memory.
37  *
38  * @author <a HREF="mailto:raphael@apache.org">Raphaël Luta</a>
39  * @author <a HREF="mailto:john.mcnally@clearink.com">John D. McNally</a>
40  * @author <a HREF="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
41  * @author <a HREF="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
42  * @version $Id: VelocityDirectLayout.java,v 1.8.2.2 2004/05/20 03:03:54 seade Exp $
43  */
44 public class VelocityDirectLayout
45     extends Layout
46 {
47     /** Logging */
48     private static Log log = LogFactory.getLog(VelocityDirectLayout.class);
49
50     /** The prefix for lookup up layout pages */
51     private String JavaDoc prefix = TurbineConstants.LAYOUT_PREFIX + "/";
52
53     /**
54      * Method called by LayoutLoader.
55      *
56      * @param data Turbine information.
57      * @exception Exception a generic exception.
58      */
59     public void doBuild(RunData data)
60         throws Exception JavaDoc
61     {
62         // Get the context needed by Velocity.
63 Context context = TurbineVelocity.getContext(data);
64
65         // variable for the screen in the layout template
66 context.put(TurbineConstants.SCREEN_PLACEHOLDER,
67                     new TemplateScreen(data));
68
69         // variable to reference the navigation screen in the layout template
70 context.put(TurbineConstants.NAVIGATION_PLACEHOLDER,
71                     new TemplateNavigation(data));
72
73         // Grab the layout template set in the VelocityPage.
74 // If null, then use the default layout template
75 // (done by the TemplateInfo object)
76 String JavaDoc templateName = data.getTemplateInfo().getLayoutTemplate();
77
78         // Set the locale and content type
79 data.getResponse().setLocale(data.getLocale());
80         data.getResponse().setContentType(data.getContentType());
81
82         log.debug("Now trying to render layout " + templateName);
83
84         // Finally, generate the layout template and send it to the browser
85 TurbineVelocity.handleRequest(context,
86                 prefix + templateName, data.getOut());
87     }
88 }
89
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