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Java > Open Source Codes > org > apache > turbine > pipeline > Renderer


1 package org.apache.turbine.pipeline;
2
3 /* ====================================================================
4  * The Apache Software License, Version 1.1
5  *
6  * Copyright (c) 2001 The Apache Software Foundation. All rights
7  * reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
20  *
21  * 3. The end-user documentation included with the redistribution,
22  * if any, must include the following acknowledgment:
23  * "This product includes software developed by the
24  * Apache Software Foundation (http://www.apache.org/)."
25  * Alternately, this acknowledgment may appear in the software itself,
26  * if and wherever such third-party acknowledgments normally appear.
27  *
28  * 4. The names "Apache" and "Apache Software Foundation" and
29  * "Apache Turbine" must not be used to endorse or promote products
30  * derived from this software without prior written permission. For
31  * written permission, please contact apache@apache.org.
32  *
33  * 5. Products derived from this software may not be called "Apache",
34  * "Apache Turbine", nor may "Apache" appear in their name, without
35  * prior written permission of the Apache Software Foundation.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals on behalf of the Apache Software Foundation. For more
53  * information on the Apache Software Foundation, please see
54  * <http://www.apache.org/>.
55  */
56
57 import org.apache.turbine.Turbine;
58 import org.apache.turbine.RunData;
59 import org.apache.turbine.modules.Module;
60 import org.apache.turbine.TurbineException;
61 import org.apache.turbine.TemplateContext;
62 import org.apache.commons.logging.Log;
63 import org.apache.commons.logging.LogFactory;
64
65 /**
66  * Helper class for rendering templates. This is used by valves to render
67  * templates. It can also be placed on the context to allow templates to render
68  * other templates.
69  *
70  * Renderers are not thread safe, they must be constructed for and used by a
71  * single RunData. In the future this class is a candidate for being made thread
72  * safe or poolable.
73  *
74  * @author <a HREF="mailto:jvanzyl@apache.org">Jason van Zyl</a>
75  * @author <a HREF="mailto:jon@latchkey.com">Jon S. Stevens</a>
76  * @author <a HREF="mailto:mikeh@apache.org">Mike Haberman</a>
77  * @author <a HREF="mailto:james@jamestaylor.org">James Taylor</a>
78  * @version $Id: Renderer.java,v 1.8 2002/04/09 17:29:35 jtaylor Exp $
79  */
80 public class Renderer
81 {
82     private static final Log log = LogFactory.getLog(Renderer.class);
83
84     /**
85      * RunData of the request this Renderer is for.
86      */
87     protected RunData data = null;
88
89     /**
90      * Construct a renderer for the given RunData.
91      */
92     public Renderer(RunData data)
93     {
94         this.data = data;
95     }
96
97     /**
98      * Render the given template. TemplateContext to use will be extracted from
99      * the RunData with which this Renderer was constructer.
100      *
101      * @param template name/path of template in the format expected by the
102      * appropriate template engine service
103      * @return Result of template merge
104      */
105     public String JavaDoc render(String JavaDoc template)
106         throws TurbineException, Exception JavaDoc
107     {
108         log.debug("Rendering template " + template);
109         
110         TemplateContext context = Module.getTemplateContext(data);
111         
112         return Module.handleRequest( context, template );
113     }
114
115     /**
116      * Use the resolver to find the template, then render.
117      */
118     public String JavaDoc render(String JavaDoc type, String JavaDoc target)
119         throws TurbineException, Exception JavaDoc
120     {
121         String JavaDoc template = Turbine.getResolver().getTemplate(type, target);
122         
123         return render( template );
124     }
125
126     /**
127      * Attemps to locate the template for target and render, if it can't find
128      * it, then it will attempt to render the template for defaultTarget
129      */
130     public String JavaDoc render(String JavaDoc type, String JavaDoc target, String JavaDoc defaultTarget)
131         throws TurbineException, Exception JavaDoc
132     {
133         String JavaDoc template = Turbine.getResolver().getTemplate(type, target);
134
135         if (Module.templateExists(template))
136         {
137             return render(template);
138         }
139         else
140         {
141             return render(type, defaultTarget);
142         }
143     }
144 }
145
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