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Java > Open Source Codes > nextapp > echo2 > webrender > util > Resource


1 /*
2  * This file is part of the Echo Web Application Framework (hereinafter "Echo").
3  * Copyright (C) 2002-2005 NextApp, Inc.
4  *
5  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
6  *
7  * The contents of this file are subject to the Mozilla Public License Version
8  * 1.1 (the "License"); you may not use this file except in compliance with
9  * the License. You may obtain a copy of the License at
10  * http://www.mozilla.org/MPL/
11  *
12  * Software distributed under the License is distributed on an "AS IS" basis,
13  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
14  * for the specific language governing rights and limitations under the
15  * License.
16  *
17  * Alternatively, the contents of this file may be used under the terms of
18  * either the GNU General Public License Version 2 or later (the "GPL"), or
19  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
20  * in which case the provisions of the GPL or the LGPL are applicable instead
21  * of those above. If you wish to allow use of your version of this file only
22  * under the terms of either the GPL or the LGPL, and not to allow others to
23  * use your version of this file under the terms of the MPL, indicate your
24  * decision by deleting the provisions above and replace them with the notice
25  * and other provisions required by the GPL or the LGPL. If you do not delete
26  * the provisions above, a recipient may use your version of this file under
27  * the terms of any one of the MPL, the GPL or the LGPL.
28  */
29
30 package nextapp.echo2.webrender.util;
31
32 import java.io.ByteArrayOutputStream JavaDoc;
33 import java.io.IOException JavaDoc;
34 import java.io.InputStream JavaDoc;
35
36 /**
37  * Provides functionality for obtaining text and binary resource files.
38  */
39 public class Resource {
40     
41     private static final int BUFFER_SIZE = 4096;
42     
43     /**
44      * A RuntimeException exception that will be thrown in the event that
45      * problems are encountered obtaining a resource.
46      */
47     public static class ResourceException extends RuntimeException JavaDoc {
48     
49         /**
50          * Creates a resource exception.
51          *
52          * @param description A description of the error.
53          */
54         private ResourceException(String JavaDoc description) {
55             super(description);
56         }
57     }
58
59     /**
60      * Retrieves the specified resource as a <code>String</code>.
61      *
62      * @param resourceName The name of the resource to be retrieved.
63      * @return The specified resource as a <code>String</code>.
64      */
65     public static String JavaDoc getResourceAsString(String JavaDoc resourceName) {
66         return getResource(resourceName).toString();
67     }
68     
69     /**
70      * Retrieves the specified resource as an array of <code>byte</code>s.
71      *
72      * @param resourceName The name of the resource to be retrieved.
73      * @return The specified resource as an array of <code>byte<code>s.
74      */
75     public static byte[] getResourceAsByteArray(String JavaDoc resourceName) {
76         return getResource(resourceName).toByteArray();
77     }
78     
79     /**
80      * An internal method used to retrieve a resource as a
81      * <code>ByteArrayOutputStream</code>.
82      *
83      * @param resourceName The name of the resource to be retrieved.
84      * @return A <code>ByteArrayOutputStream</code> of the content of the
85      * resource.
86      */
87     private static ByteArrayOutputStream JavaDoc getResource(String JavaDoc resourceName) {
88         InputStream JavaDoc in = null;
89         byte[] buffer = new byte[BUFFER_SIZE];
90         ByteArrayOutputStream JavaDoc out = null;
91         int bytesRead = 0;
92         
93         try {
94             in = Resource.class.getResourceAsStream(resourceName);
95             if (in == null) {
96                 throw new ResourceException("Resource does not exist: \"" + resourceName + "\"");
97             }
98             out = new ByteArrayOutputStream JavaDoc();
99             do {
100                 bytesRead = in.read(buffer);
101                 if (bytesRead > 0) {
102                     out.write(buffer, 0, bytesRead);
103                 }
104             } while (bytesRead > 0);
105         } catch (IOException JavaDoc ex) {
106             throw new ResourceException("Cannot get resource: \"" + resourceName + "\": " + ex);
107         } finally {
108             if (in != null) { try { in.close(); } catch (IOException JavaDoc ex) { } }
109         }
110         
111         return out;
112     }
113
114     /** Non-instantiable class. */
115     private Resource() { }
116 }
117
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