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Java > Open Source Codes > org > apache > turbine > services > template > mapper > ClassMapper


1 package org.apache.turbine.services.template.mapper;
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 java.util.ArrayList JavaDoc;
20 import java.util.Arrays JavaDoc;
21 import java.util.List JavaDoc;
22
23 import org.apache.commons.lang.StringUtils;
24
25 import org.apache.turbine.modules.Loader;
26
27 import org.apache.commons.logging.Log;
28 import org.apache.commons.logging.LogFactory;
29
30 import org.apache.turbine.services.template.TemplateService;
31
32 /**
33  * This mapper tries to map Template names to class names. If no direct match
34  * is found, it tries matches "upwards" in the package hierarchy until either
35  * a match is found or the root is hit. Then it returns the name of the
36  * default class from the TemplateEngineService.
37  *
38  * 1. about.directions.Driving <- direct matching the template to the class name
39  * 2. about.directions.Default <- matching the package, class name is Default
40  * 3. about.Default <- stepping up in the package hierarchy, looking for Default
41  * 4. Default <- Class called "Default" without package
42  * 5. VelocityScreen <- The class configured by the Service (VelocityService) to
43  *
44  * Please note, that no actual packages are searched. This is the scope of the
45  * TemplateEngine Loader which is passed at construction time.
46  *
47  * @author <a HREF="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
48  * @version $Id: ClassMapper.java,v 1.1.2.2 2004/05/20 03:06:48 seade Exp $
49  */
50
51 public class ClassMapper
52     extends BaseMapper
53     implements Mapper
54 {
55     /** The loader for actually trying out the package names */
56     private Loader loader = null;
57
58     /** Logging */
59     private static Log log = LogFactory.getLog(ClassMapper.class);
60
61     /**
62      * Default C'tor. If you use this C'tor, you must use
63      * the bean setter to set the various properties needed for
64      * this mapper before first usage.
65      */
66     public ClassMapper()
67     {
68     }
69
70     /**
71      * Get the Loader value.
72      * @return the Loader value.
73      */
74     public Loader getLoader()
75     {
76         return loader;
77     }
78
79     /**
80      * Set the Loader value.
81      * @param loader The new Loader value.
82      */
83     public void setLoader(Loader loader)
84     {
85         this.loader = loader;
86         log.debug("Loader is " + this.loader);
87     }
88
89     /**
90      * Strip off a possible extension, replace all "," with "."
91      * Look through the given package path until a match is found.
92      *
93      * @param template The template name.
94      * @return A class name for the given template.
95      */
96     public String JavaDoc doMapping(String JavaDoc template)
97     {
98         log.debug("doMapping(" + template + ")");
99
100         // Copy our elements into an array
101 List JavaDoc components
102             = new ArrayList JavaDoc(Arrays.asList(StringUtils.split(
103                                               template,
104                                               String.valueOf(TemplateService.TEMPLATE_PARTS_SEPARATOR))));
105         int componentSize = components.size() - 1 ;
106
107         // This method never gets an empty string passed.
108 // So this is never < 0
109 String JavaDoc className = (String JavaDoc) components.get(componentSize);
110         components.remove(componentSize--);
111
112         log.debug("className is " + className);
113
114         // Strip off a possible Extension
115 int dotIndex = className.lastIndexOf(TemplateService.EXTENSION_SEPARATOR);
116         className = (dotIndex < 0) ? className : className.substring(0, dotIndex);
117
118         // This is an optimization. If the name we're looking for is
119 // already the default name for the template, don't do a "first run"
120 // which looks for an exact match.
121 boolean firstRun = !className.equals(TemplateService.DEFAULT_NAME);
122
123         for(;;)
124         {
125             String JavaDoc pkg = StringUtils.join(components.iterator(), String.valueOf(separator));
126             StringBuffer JavaDoc testName = new StringBuffer JavaDoc();
127
128             log.debug("classPackage is now: " + pkg);
129
130             if (!components.isEmpty())
131             {
132                 testName.append(pkg);
133                 testName.append(separator);
134             }
135
136             testName.append((firstRun)
137                 ? className
138                 : TemplateService.DEFAULT_NAME);
139
140             log.debug("Looking for " + testName);
141             try
142             {
143                 loader.getAssembler(testName.toString());
144                 log.debug("Found it, returning " + testName);
145                 return testName.toString();
146             }
147             catch (Exception JavaDoc e)
148             {
149                 // Not found. Go on.
150 }
151
152             if (firstRun)
153             {
154                 firstRun = false;
155             }
156             else
157             {
158                 if (components.isEmpty())
159                 {
160                     break; // for(;;)
161 }
162                 components.remove(componentSize--);
163             }
164         }
165
166         log.debug("Returning default");
167         return getDefaultName(template);
168     }
169 }
170
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