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Java > Open Source Codes > org > roller > presentation > velocity > WebappResourceLoader


1 package org.roller.presentation.velocity;
2
3 import org.apache.commons.collections.ExtendedProperties;
4 import org.apache.commons.logging.Log;
5 import org.apache.commons.logging.LogFactory;
6 import org.apache.velocity.exception.ResourceNotFoundException;
7 import org.apache.velocity.runtime.resource.Resource;
8 import org.apache.velocity.runtime.resource.loader.ResourceLoader;
9 import org.roller.presentation.RollerContext;
10
11 import java.io.InputStream JavaDoc;
12
13 import javax.servlet.ServletContext JavaDoc;
14
15 /**
16  * Tries to load Velocity resources from the Webapp.
17  * This class borrows heavily from
18  * org.apache.velocity.tools.view.servlet.WebappLoader
19  * http://cvs.apache.org/viewcvs/jakarta-velocity-
20  * tools/view/src/java/org/apache/velocity/tools/view/servlet/WebappLoader.java?
21  * rev=1.1.1.1&content-type=text/vnd.viewcvs-markup
22  *
23  * @author Lance Lavandowska
24  */
25 public class WebappResourceLoader extends ResourceLoader
26 {
27     private static Log mLogger =
28         LogFactory.getFactory().getInstance(WebappResourceLoader.class);
29     
30     private static ServletContext JavaDoc mContext = null;
31   
32     /**
33      * @see org.apache.velocity.runtime.resource.loader.ResourceLoader#init(org.apache.commons.collections.ExtendedProperties)
34      */
35     public void init(ExtendedProperties arg0)
36     {
37         rsvc.info("WebappResourceLoader : initialization starting.");
38
39         this.getContext();
40         if (mContext == null)
41         {
42             mLogger.warn("WebappResourceLoader : Unable to find ServletContext!");
43         }
44
45         rsvc.info("WebappResourceLoader : initialization complete.");
46     }
47     
48     private ServletContext JavaDoc getContext()
49     {
50         if (mContext == null)
51         {
52             mContext = RollerContext.getServletContext();
53         }
54         return mContext;
55     }
56     
57     public static void setServletContext(ServletContext JavaDoc context)
58     {
59         mContext = context;
60     }
61     
62     /**
63      * @see org.apache.velocity.runtime.resource.loader.ResourceLoader#getResourceStream(java.lang.String)
64      */
65     public InputStream JavaDoc getResourceStream(String JavaDoc name)
66         throws ResourceNotFoundException
67     {
68         InputStream JavaDoc result = null;
69         
70         if (name == null || name.length() == 0)
71         {
72             throw new ResourceNotFoundException ("No template name provided");
73         }
74         
75         try
76         {
77             if (!name.startsWith("/"))
78                 name = "/" + name;
79
80             result = getContext().getResourceAsStream( name );
81         }
82         catch( NullPointerException JavaDoc npe)
83         {
84             String JavaDoc msg = "WebappResourceLoader.getResourceStream(): " + name;
85             if (mContext == null)
86             {
87                 mLogger.info("WebappResourceLoader("+name+"): ServletContext is null");
88                 msg += "\n\tServletContext is null";
89             }
90             throw new ResourceNotFoundException(msg);
91         }
92         catch( Exception JavaDoc fnfe )
93         {
94             /*
95              * log and convert to a general Velocity ResourceNotFoundException
96              */
97             throw new ResourceNotFoundException( fnfe.getMessage() );
98         }
99         
100         return result;
101     }
102     
103     /**
104      * Defaults to return false.
105      * @see org.apache.velocity.runtime.resource.loader.ResourceLoader#isSourceModified(org.apache.velocity.runtime.resource.Resource)
106      */
107     public boolean isSourceModified(Resource arg0)
108     {
109         return false;
110     }
111     
112     /**
113      * Defaults to return 0.
114      * @see org.apache.velocity.runtime.resource.loader.ResourceLoader#getLastModified(org.apache.velocity.runtime.resource.Resource)
115      */
116     public long getLastModified(Resource arg0)
117     {
118         return 0;
119     }
120 }
121
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