TurbineTemplateService


1   package org.apache.fulcrum.template;
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 java.io.File  ;
58  import java.io.OutputStream  ;
59  import java.io.Writer  ;
60  import java.util.HashMap  ;
61  
62  import org.apache.fulcrum.BaseService;
63  import org.apache.fulcrum.InitializationException;
64  import org.apache.fulcrum.ServiceException;
65  
66  /**
67   * This service provides a method for mapping templates to their
68   * appropriate Screens or Navigations.  It also allows templates to
69   * define a layout/navigations/screen modularization within the
70   * template structure.  It also performs caching if turned on in the
71   * properties file.
72   *
73   * Since everything is keyed off the template variable,
74   * if data.getParameters().getString("template") returns
75   * /about_us/directions/driving.vm, the search for the
76   * Screen class is as follows (in order):
77   *
78   * 1. about_us.directions.Driving
79   * 2. about_us.directions.Default
80   * 3. about_us.Default
81   * 4. Default
82   * 5. VelocityScreen
83   *
84   * If the template variable does not exist, then VelocityScreen will be
85   * executed and templates/screens/index.vm will be executed.
86   * If index.vm is not found or if the template is invalid or Velocity
87   * execution throws an exception of any reason, then
88   * templates/screens/error.vm will be executed.
89   *
90   * For the Layouts and Navigations, the following paths will be
91   * searched in the layouts and navigations template
92   * subdirectories (in order):
93   *
94   * 1./about_us/directions/driving.vm
95   * 2./about_us/directions/default.vm
96   * 3./about_us/default.vm
97   * 4./default.vm
98   *
99   * @author <a HREF="mailto:jmcnally@collab.net">John D. McNally</a>
100  * @author <a HREF="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
101  * @author <a HREF="mailto:jvanzyl@apache.org">Jason van Zyl</a>
102  * @author <a HREF="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
103  * @author <a HREF="mailto:ilkka.priha@simsoft.fi">Ilkka Priha</a>
104  * @version $Id: TurbineTemplateService.java,v 1.1 2004/11/12 10:26:06 epugh Exp $
105  */
106 public class TurbineTemplateService
107     extends BaseService
108     implements TemplateService
109 {
110     /**
111      * The default file extension used as a registry key when a
112      * template's file extension cannot be determined.
113      */
114     protected static final String   NO_FILE_EXT = "";
115 
116     /**
117      * Default extension for templates.
118      */
119     private String   defaultExtension;
120 
121     /**
122      * The mappings of template file extensions to {@link
123      * org.apache.fulcrum.template.TemplateEngineService}
124      * implementations.  Implementing template engines can locate
125      * templates within the capability of any resource loaders they
126      * may posses, and other template engines are stuck with file
127      * based template hierarchy only.
128      */
129     private HashMap   templateEngineRegistry;
130 
131     public TurbineTemplateService()
132     {
133     }
134 
135     /**
136      * Called the first time the Service is used.
137      *
138      * @exception InitializationException.
139      */
140     public void init()
141         throws InitializationException
142     {
143         setInit(true);
144     }
145 
146     /**
147      * Translates the supplied template paths into their Turbine-canonical
148      * equivalent (probably absolute paths).
149      *
150      * @param templatePaths An array of template paths.
151      * @return An array of translated template paths.
152      */
153     public String  [] translateTemplatePaths(String  [] templatePaths)
154     {
155         for (int i = 0; i < templatePaths.length; i++)
156         {
157             templatePaths[i] = getRealPath(templatePaths[i]);
158         }
159         return templatePaths;
160     }
161 
162     /**
163      * Looks for the specified template file in each of the specified paths.
164      *
165      * @param template The template file to check for the existance of.
166      * @param templatePaths The paths to check for the template.
167      *
168      * @return true if a match is found in one of the supplied paths, or false.
169      */
170     public boolean templateExists(String   template,
171                                   String  [] templatePaths)
172     {
173         for (int i = 0; i < templatePaths.length; i++)
174         {
175             if (new File  (templatePaths[i],template).exists())
176             {
177                 return true;
178             }
179         }
180         return false;
181     }
182 
183     /**
184      * Determine if a template exists. Delegates to the appropriate {@link 
185      * org.apache.fulcrum.template.TemplateEngineService} to check the 
186      * existance of the specified template. If no template engine service is
187      * found for the template, false is returned.
188      * 
189      * @param template The template file to check for the existence of.
190      *
191      * @return true if there is a template engine service registered for the
192      *         given template, and it reports that the template exists, 
193      *         otherwise false.
194      */
195     public boolean templateExists(String   template)
196     {
197         TemplateEngineService tes = getTemplateEngineService(template);
198 
199         if (tes != null)
200         {
201             return tes.templateExists(template);
202         }
203         else
204         {
205             return false;
206         }
207     }
208 
209     /**
210      * Registers the provided template engine for use by the
211      * <code>TemplateService</code>.
212      *
213      * @param service The <code>TemplateEngineService</code> to register.
214      */
215     public synchronized void registerTemplateEngineService(TemplateEngineService service)
216     {
217         // Clone the registry to write to non-sync'd
218         // Map implementations.
219         HashMap   registry = templateEngineRegistry != null ?
220             (HashMap  ) templateEngineRegistry.clone() : new HashMap  ();
221 
222         String  [] exts = service.getAssociatedFileExtensions();
223 
224         for (int i = 0; i < exts.length; i++)
225         {
226             registry.put(exts[i], service);
227         }
228         templateEngineRegistry = registry;
229     }
230 
231     /**
232      * The {@link org.apache.fulcrum.template.TemplateEngineService}
233      * associated with the specified template's file extension.
234      *
235      * @param template The template name.
236      * @return The template engine service.
237      */
238     protected TemplateEngineService getTemplateEngineService(String   template)
239     {
240         HashMap   registry = templateEngineRegistry;
241         if (registry != null && template != null)
242         {
243             int dotIndex = template.lastIndexOf('.');
244             String   ext = dotIndex == -1 ?
245                 defaultExtension : template.substring(dotIndex + 1);
246             return (TemplateEngineService) registry.get(ext);
247         }
248         else
249         {
250             return null;
251         }
252     }
253 
254     public String   handleRequest(TemplateContext context, String   template)
255         throws ServiceException
256     {
257         TemplateEngineService tes = getTemplateEngineService(template);
258         return tes.handleRequest(context, template);
259     }
260 
261     public void handleRequest(TemplateContext context, String   template,
262                               OutputStream   outputStream)
263         throws ServiceException
264     {
265         TemplateEngineService tes = getTemplateEngineService(template);
266         tes.handleRequest(context, template, outputStream);
267     }
268 
269     public void handleRequest(TemplateContext context, String   template,
270                               Writer   writer)
271         throws ServiceException
272     {
273         TemplateEngineService tes = getTemplateEngineService(template);
274         tes.handleRequest(context, template, writer);
275     }
276 
277     public TemplateContext getTemplateContext()
278     {
279         return new DefaultTemplateContext();
280     }
281 }
282
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags