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1   package org.apache.turbine.services.template.mapper;
2   
3   
4   /*
5    * Licensed to the Apache Software Foundation (ASF) under one
6    * or more contributor license agreements.  See the NOTICE file
7    * distributed with this work for additional information
8    * regarding copyright ownership.  The ASF licenses this file
9    * to you under the Apache License, Version 2.0 (the
10   * "License"); you may not use this file except in compliance
11   * with the License.  You may obtain a copy of the License at
12   *
13   *   http://www.apache.org/licenses/LICENSE-2.0
14   *
15   * Unless required by applicable law or agreed to in writing,
16   * software distributed under the License is distributed on an
17   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
18   * KIND, either express or implied.  See the License for the
19   * specific language governing permissions and limitations
20   * under the License.
21   */
22  
23  
24  import java.util.HashMap;
25  import java.util.Map;
26  
27  import org.apache.commons.lang.StringUtils;
28  import org.apache.turbine.services.template.TemplateEngineService;
29  import org.apache.turbine.services.template.TurbineTemplate;
30  
31  /**
32   * A base class for the various mappers which contains common
33   * code.
34   *
35   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
36   * @version $Id: BaseMapper.java 1706239 2015-10-01 13:18:35Z tv $
37   */
38  
39  public abstract class BaseMapper
40  {
41      /** True if this mapper should cache template -> name mappings */
42      private boolean useCache = false;
43  
44      /** Default cache size. Just a number out of thin air. Will be set at init time */
45      private int cacheSize = 5;
46  
47      /** The internal template -> name mapping cache */
48      private Map<String, String> templateCache = null;
49  
50      /** The name of the default property to pull from the Template Engine Service if the default is requested */
51      protected String defaultProperty;
52  
53      /** The separator used to concatenate the result parts for this mapper. */
54      protected char separator;
55  
56      // Note: You might _not_ use TurbineTemplate.<xxx> in the C'tor and the init method.
57      // The service isn't configured yet and if you do, the Broker will try to reinit the
58      // Service which leads to an endless loop and a deadlock.
59  
60      /**
61       * Default C'tor. If you use this C'tor, you must use
62       * the bean setter to set the various properties needed for
63       * this mapper before first usage.
64       */
65      public BaseMapper()
66      {
67          // empty
68      }
69  
70      /**
71       * Get the CacheSize value.
72       * @return the CacheSize value.
73       */
74      public int getCacheSize()
75      {
76          return cacheSize;
77      }
78  
79      /**
80       * Set the CacheSize value.
81       * @param cacheSize The new CacheSize value.
82       */
83      public void setCacheSize(int cacheSize)
84      {
85          this.cacheSize = cacheSize;
86      }
87  
88      /**
89       * Get the UseCache value.
90       * @return the UseCache value.
91       */
92      public boolean isUseCache()
93      {
94          return useCache;
95      }
96  
97      /**
98       * Set the UseCache value.
99       * @param useCache The new UseCache value.
100      */
101     public void setUseCache(boolean useCache)
102     {
103         this.useCache = useCache;
104     }
105 
106     /**
107      * Get the DefaultProperty value.
108      * @return the DefaultProperty value.
109      */
110     public String getDefaultProperty()
111     {
112         return defaultProperty;
113     }
114 
115     /**
116      * Set the DefaultProperty value.
117      * @param defaultProperty The new DefaultProperty value.
118      */
119     public void setDefaultProperty(String defaultProperty)
120     {
121         this.defaultProperty = defaultProperty;
122     }
123 
124     /**
125      * Get the Separator value.
126      * @return the Separator value.
127      */
128     public char getSeparator()
129     {
130         return separator;
131     }
132 
133     /**
134      * Set the Separator value.
135      * @param separator The new Separator value.
136      */
137     public void setSeparator(char separator)
138     {
139         this.separator = separator;
140     }
141 
142     /**
143      * Initializes the Mapper. Must be called before the mapper might be used.
144      */
145     public void init()
146     {
147         if (useCache)
148         {
149             templateCache = new HashMap<String, String>(cacheSize);
150         }
151     }
152 
153     /**
154      * Returns the default name for the passed Template.
155      * If the passed template has no extension,
156      * the default extension is assumed.
157      * If the template is empty, the default template is
158      * returned.
159      *
160      * @param template The template name.
161      *
162      * @return the mapped default name for the template.
163      */
164 
165     public String getDefaultName(String template)
166     {
167         // We might get a Name without an extension passed. If yes, then we use
168         // the Default extension
169 
170         TemplateEngineService tes
171             = TurbineTemplate.getTemplateEngineService(template);
172 
173         if (StringUtils.isEmpty(template) || (tes == null))
174         {
175             return TurbineTemplate.getDefaultTemplate();
176         }
177 
178         String defaultName = (String) tes.getTemplateEngineServiceConfiguration()
179             .get(defaultProperty);
180 
181         return StringUtils.isEmpty(defaultName)
182             ? TurbineTemplate.getDefaultTemplate()
183             : defaultName;
184     }
185 
186     /**
187      * Return the first match name for the given template name.
188      *
189      * @param template The template name.
190      *
191      * @return The first matching class or template name.
192      */
193     public String getMappedName(String template)
194     {
195         if (StringUtils.isEmpty(template))
196         {
197             return null;
198         }
199 
200         if (useCache && templateCache.containsKey(template))
201         {
202             return templateCache.get(template);
203         }
204 
205         String res = doMapping(template);
206 
207         // Never cache "null" return values and empty Strings.
208         if (useCache && StringUtils.isNotEmpty(res))
209         {
210             templateCache.put(template, res);
211         }
212 
213         return res;
214     }
215 
216     /**
217      * The actual mapping implementation class. It
218      * is guaranteed that never an empty or null
219      * template name is passed to it. This might
220      * return null.
221      *
222      * @param template The template name.
223      * @return The mapped class or template name.
224      */
225     public abstract String doMapping(String template);
226 }