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Java > Open Source Codes > org > apache > jetspeed > services > resources > VariableResourcesService


1 /*
2  * Copyright 2000-2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.jetspeed.services.resources;
18
19 // Java Core Classes
20 import java.io.File JavaDoc;
21 import java.io.IOException JavaDoc;
22 import java.util.Enumeration JavaDoc;
23 import java.util.Hashtable JavaDoc;
24 import java.util.Vector JavaDoc;
25 import javax.servlet.ServletConfig JavaDoc;
26 import javax.servlet.ServletContext JavaDoc;
27
28 // Turbine stuff.
29 import org.apache.commons.configuration.Configuration;
30 import org.apache.turbine.services.resources.ResourceService;
31 import org.apache.turbine.services.resources.TurbineResourceService;
32 import org.apache.turbine.services.TurbineServices;
33 import org.apache.turbine.services.InitializationException;
34
35 // Jetspeed classes
36 import org.apache.jetspeed.services.logging.JetspeedLogFactoryService;
37 import org.apache.jetspeed.services.logging.JetspeedLogger;
38
39 /**
40  * <p>This implementation of the <code>resourcesService</code> relies
41  * on an external properties file for storing the configuration keys
42  * and values</p>
43  *
44  * <P>In order to be compatible with legacy applications, this implementation
45  * kept a static method for initializing the service, so it's still possible
46  * to write the following code:
47  * <p><code>
48  * TurbineResourceService.setPropertiesName("d:/conf/Turbine.properties");
49  * Vector myVar = TurbineResources.getVector("myvar");
50  * </code></p>
51  *
52  * <p>This implementation allows the use of several pre-defined variables within
53  * the configuration file. The variables are identified by the following
54  * sequence of tokens: ${<varname>}. Varname is always folded to lowercase.</p>
55  * <P>The predefined variables are:
56  * <ul>
57  * <li>webapp.dir: base directory for the web application
58  * <li>jvm.dir: JVM startup directory
59  * </ul>
60  * </p>
61  * <p>The init parameters of the servlet are also imported as default variables.
62  * They may override the previously defined default variables
63  * </p>
64  *
65  * @author <a HREF="mailto:raphael@apache.org">Raphaël Luta</a>
66  * @version $Id: VariableResourcesService.java,v 1.15 2004/02/23 03:29:53 jford Exp $
67  */
68 public class VariableResourcesService extends TurbineResourceService
69 {
70     /**
71      * Static initialization of the logger for this class
72      */
73     private static final JetspeedLogger logger = JetspeedLogFactoryService.getLogger(VariableResourcesService.class.getName());
74     
75     public static final String JavaDoc WEBAPP_DIR="webapp.dir";
76     public static final String JavaDoc WEB_DIR="web.dir";
77     public static final String JavaDoc JVM_DIR="jvm.dir";
78     public static final String JavaDoc START_TOKEN="${";
79     public static final String JavaDoc END_TOKEN="}";
80     
81     /** The container for the generic resources. */
82     private Hashtable JavaDoc variables = null;
83
84     /** The container for the generic resources. */
85     private Hashtable JavaDoc strings = null;
86     private Hashtable JavaDoc vectors = null;
87     private Hashtable JavaDoc arrays = null;
88
89
90     /**
91      * Late init. Don't return control until early init says we're done.
92      */
93     public void init( )
94     {
95         while( !getInit() ) {
96             try {
97                 Thread.sleep(500);
98             } catch (InterruptedException JavaDoc ie ) {
99                 logger.info("VariableResources service: Waiting for init()..." );
100             }
101         }
102     }
103
104
105     /**
106      * This method is called when the Service is initialized
107      *
108      * @param config a ServletConfig object
109      */
110     public synchronized void init(ServletConfig JavaDoc config) throws InitializationException
111     {
112         if (getInit()) return;
113         String JavaDoc props = config.getInitParameter(TurbineServices.PROPERTIES_PATH_KEY);
114
115         variables = new Hashtable JavaDoc();
116         strings = new Hashtable JavaDoc();
117         vectors = new Hashtable JavaDoc();
118         arrays = new Hashtable JavaDoc();
119         initVariables(config);
120
121         super.init(config);
122     }
123
124     /**
125      * Initializer method that sets up the generic resources.
126      *
127      * @param confs A Configurations object.
128      */
129     private void initVariables(ServletConfig JavaDoc config)
130     {
131         ServletContext JavaDoc ctxt = config.getServletContext();
132         
133         String JavaDoc path = ctxt.getRealPath("/");
134         
135         // define web app dir
136 if (path != null) {
137             variables.put(WEBAPP_DIR, normalizePath(path) );
138         }
139         
140         // FIXME. the following code blocks on Tomcat
141 // when loaded on startup
142 /*
143         path = ctxt.getContext("/").getRealPath("/");
144         if (path != null ) {
145             variables.put(WEB_DIR, normalizePath(path) );
146         }
147         */
148
149         // define JVM app dir
150 try {
151             path = new File JavaDoc(".").getCanonicalPath();
152             if (path != null) {
153                 variables.put(JVM_DIR, normalizePath(path) );
154             }
155         } catch (IOException JavaDoc e) {
156             //very unlikely that the JVM can't
157 //resolve its path
158 //But logging it anyway...
159 logger.error( "Exception define JVM app dir", e );
160         }
161
162         // load servlet init parameters as variables, they may override
163 // the previously defined variables. All param names are folded
164 // to lower case
165
166         Enumeration JavaDoc en = config.getInitParameterNames();
167         while( en.hasMoreElements() ) {
168             String JavaDoc paramName = (String JavaDoc)en.nextElement();
169             String JavaDoc paramValue = config.getInitParameter(paramName);
170             variables.put(paramName.toLowerCase(),paramValue);
171         }
172             
173     }
174
175     private static String JavaDoc normalizePath(String JavaDoc path) {
176         // change all separators to forward
177 // slashes
178 if (File.separatorChar != '/') {
179             path = path.replace(File.separatorChar,'/');
180         }
181         
182         // remove any trailing slash
183 if (path.endsWith("/")) {
184             path = path.substring(0,path.length()-1);
185         }
186         
187         return path;
188     }
189     
190     protected void setVariables(Hashtable JavaDoc vars)
191     {
192         synchronized (this)
193         {
194             this.variables = vars;
195             this.strings = new Hashtable JavaDoc();
196             this.vectors = new Hashtable JavaDoc();
197             this.arrays = new Hashtable JavaDoc();
198         }
199     }
200     
201     protected String JavaDoc substituteString( String JavaDoc base ) {
202         if (base == null) return null;
203         
204         int begin = -1;
205         int end = -1;
206         int prec = 0-END_TOKEN.length();
207         String JavaDoc var = null;
208         StringBuffer JavaDoc result = new StringBuffer JavaDoc();
209         
210         // FIXME: we should probably allow the escaping of the start token
211 while ( ((begin=base.indexOf(START_TOKEN,prec+END_TOKEN.length()))>-1)
212                 && ((end=base.indexOf(END_TOKEN,begin))>-1) ) {
213             
214             result.append(base.substring(prec+END_TOKEN.length(),begin));
215             var = base.substring(begin+START_TOKEN.length(),end);
216             if (variables.get(var)!=null) {
217                 result.append(variables.get(var));
218             }
219             prec=end;
220         }
221         result.append(base.substring(prec+END_TOKEN.length(),base.length()));
222         
223         return result.toString();
224     }
225         
226         
227     /**
228      * The purpose of this method is to get the configuration resource
229      * with the given name as a string.
230      *
231      * @param name The resource name.
232      * @return The value of the resource as a string.
233      */
234     public String JavaDoc getString(String JavaDoc name)
235     {
236         String JavaDoc std = (String JavaDoc)strings.get(name);
237         
238         if (std == null) {
239             std = substituteString(super.getString(name));
240             if (std != null) strings.put(name,std);
241         }
242         
243         return std;
244     }
245
246     /**
247      * The purpose of this method is to get the configuration resource
248      * with the given name as a string, or a default value.
249      *
250      * @param name The resource name.
251      * @param def The default value of the resource.
252      * @return The value of the resource as a string.
253      */
254     public String JavaDoc getString(String JavaDoc name,
255                                    String JavaDoc def)
256     {
257         String JavaDoc std = getString(name);
258         
259         if (std == null)
260             std = substituteString(def);
261     
262         return std;
263     }
264
265     /**
266      * The purpose of this method is to get the configuration resource
267      * with the given name as a string array.
268      *
269      * @param name The resource name.
270      * @return The value of the resource as a string array.
271      */
272     public String JavaDoc[] getStringArray(String JavaDoc name)
273     {
274         String JavaDoc[] std = (String JavaDoc[])arrays.get(name);
275         if (std==null) {
276             std = super.getStringArray(name);
277             if (std != null) {
278                 for(int i=0;i<std.length;i++) {
279                     std[i]=substituteString(std[i]);
280                 }
281                 arrays.put(name,std);
282             }
283         }
284         
285         return std;
286     }
287
288     /**
289      * The purpose of this method is to get the configuration resource
290      * with the given name as a vector.
291      *
292      * @param name The resource name.
293      * @return The value of the resource as a vector.
294      */
295     public Vector JavaDoc getVector(String JavaDoc name)
296     {
297         Vector JavaDoc std = (Vector JavaDoc)vectors.get(name);
298         
299         if (std==null) {
300             std = super.getVector(name);
301             if (std != null) {
302                 Vector JavaDoc newstd = new Vector JavaDoc();
303                 Enumeration JavaDoc en = std.elements();
304                 while (en.hasMoreElements()) {
305                     newstd.addElement(substituteString((String JavaDoc)en.nextElement()));
306                 }
307                 std = newstd;
308                 vectors.put(name,std);
309             }
310         }
311         
312         return std;
313     }
314
315     /**
316      * The purpose of this method is to get the configuration resource
317      * with the given name as a vector, or a default value.
318      *
319      * @param name The resource name.
320      * @param def The default value of the resource.
321      * @return The value of the resource as a vector.
322      */
323     public Vector JavaDoc getVector(String JavaDoc name,
324                                    Vector JavaDoc def)
325     {
326         Vector JavaDoc std = getVector(name);
327         if ( std == null) {
328             if (def != null) {
329                 std = new Vector JavaDoc();
330                 Enumeration JavaDoc en = def.elements();
331                 while (en.hasMoreElements()) {
332                     std.addElement(substituteString((String JavaDoc)en.nextElement()));
333                 }
334             }
335         }
336
337         return std;
338     }
339
340     /**
341      * The purpose of this method is to extract a subset of configuraton
342      * resources sharing a common name prefix. The prefix is stripped
343      * from the names of the resulting resources.
344      *
345      * @param prefix the common name prefix
346      * @return A ResourceService providing the subset of configuration.
347      */
348     public ResourceService getResources(String JavaDoc prefix)
349     {
350         Configuration config = getConfiguration().subset(prefix);
351         
352         if (config == null)
353         {
354             return null;
355         }
356         
357         VariableResourcesService res = new VariableResourcesService();
358         try
359         {
360             res.init(config);
361         }
362         catch (Exception JavaDoc e)
363         {
364             logger.error( "Unable to init resources for " + prefix, e );
365         }
366         res.setVariables(this.variables);
367         return (ResourceService)res;
368     }
369
370
371 }
372
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