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Java > Open Source Codes > org > apache > cayenne > gen > ClassGeneratorResourceLoader


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19
20 package org.apache.cayenne.gen;
21
22 import java.io.BufferedInputStream JavaDoc;
23 import java.io.File JavaDoc;
24 import java.io.FileInputStream JavaDoc;
25 import java.io.FileNotFoundException JavaDoc;
26 import java.io.InputStream JavaDoc;
27
28 import org.apache.velocity.exception.ResourceNotFoundException;
29 import org.apache.velocity.runtime.resource.loader.FileResourceLoader;
30
31 /**
32  * Velocity template resource loader customized for Cayenne use. Supports loading
33  * templates from the thread ClassLoader and from relative and absolute paths.
34  *
35  * @since 1.2
36  * @author Andrus Adamchik
37  */
38 public class ClassGeneratorResourceLoader extends FileResourceLoader {
39
40     /**
41      * Returns resource as InputStream. First calls super implementation. If resource
42      * wasn't found, it attempts to load it from current directory or as an absolute path.
43      */
44     public synchronized InputStream JavaDoc getResourceStream(String JavaDoc name)
45             throws ResourceNotFoundException {
46
47         InputStream JavaDoc stream = loadFromRelativePath(name);
48         if (stream != null) {
49             return stream;
50         }
51
52         stream = loadFromAbsPath(name);
53         if (stream != null) {
54             return stream;
55         }
56
57         stream = loadFromThreadClassLoader(name);
58         if (stream != null) {
59             return stream;
60         }
61
62         stream = loadFromThisClassLoader(name);
63         if (stream != null) {
64             return stream;
65         }
66
67         throw new ResourceNotFoundException("Couldn't find resource '"
68                 + name
69                 + "'. Searched filesystem path and classpath");
70     }
71
72     protected InputStream JavaDoc loadFromRelativePath(String JavaDoc name) {
73         try {
74             return super.getResourceStream(name);
75         }
76         catch (ResourceNotFoundException rnfex) {
77             return null;
78         }
79     }
80
81     protected InputStream JavaDoc loadFromAbsPath(String JavaDoc name) {
82         try {
83             File JavaDoc file = new File JavaDoc(name);
84             return (file.canRead()) ? new BufferedInputStream JavaDoc(new FileInputStream JavaDoc(file
85                     .getAbsolutePath())) : null;
86
87         }
88         catch (FileNotFoundException JavaDoc fnfe) {
89             return null;
90         }
91     }
92
93     protected InputStream JavaDoc loadFromThreadClassLoader(String JavaDoc name) {
94         return Thread.currentThread().getContextClassLoader().getResourceAsStream(name);
95     }
96
97     protected InputStream JavaDoc loadFromThisClassLoader(String JavaDoc name) {
98         return getClass().getClassLoader().getResourceAsStream(name);
99     }
100 }
101
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