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Java > Open Source Codes > org > objectstyle > cayenne > util > WebApplicationResourceLocator


1 /* ====================================================================
2  *
3  * The ObjectStyle Group Software License, version 1.1
4  * ObjectStyle Group - http://objectstyle.org/
5  *
6  * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
7  * of the software. All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
20  *
21  * 3. The end-user documentation included with the redistribution, if any,
22  * must include the following acknowlegement:
23  * "This product includes software developed by independent contributors
24  * and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
25  * Alternately, this acknowlegement may appear in the software itself,
26  * if and wherever such third-party acknowlegements normally appear.
27  *
28  * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
29  * or promote products derived from this software without prior written
30  * permission. For written permission, email
31  * "andrus at objectstyle dot org".
32  *
33  * 5. Products derived from this software may not be called "ObjectStyle"
34  * or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
35  * names without prior written permission.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals and hosted on ObjectStyle Group web site. For more
53  * information on the ObjectStyle Group, please see
54  * <http://objectstyle.org/>.
55  */
56 package org.objectstyle.cayenne.util;
57
58 import java.net.MalformedURLException JavaDoc;
59 import java.net.URL JavaDoc;
60 import java.util.ArrayList JavaDoc;
61 import java.util.Iterator JavaDoc;
62 import java.util.List JavaDoc;
63
64 import javax.servlet.ServletContext JavaDoc;
65
66 import org.apache.commons.collections.Predicate;
67 import org.apache.log4j.Logger;
68 import org.objectstyle.cayenne.conf.Configuration;
69
70 /**
71  * A ResourceLocator that can find resources relative to web application context.
72  *
73  * @author Andrei Adamchik
74  */
75 public class WebApplicationResourceLocator extends ResourceLocator {
76
77     private static Logger logObj;
78
79     // Create a Predicate that will enable logging only when
80 // Configuration.isLoggingConfigured() returns true.
81 // The passed predicate argument is ignored.
82 static {
83         Predicate p = new Predicate() {
84
85             public boolean evaluate(Object JavaDoc o) {
86                 return Configuration.isLoggingConfigured();
87             }
88         };
89
90         logObj = new PredicateLogger(WebApplicationResourceLocator.class, p);
91     }
92
93     protected ServletContext JavaDoc context;
94     protected List JavaDoc additionalContextPaths;
95
96     /**
97      * @since 1.2
98      */
99     public WebApplicationResourceLocator() {
100         this.additionalContextPaths = new ArrayList JavaDoc();
101         this.addFilesystemPath("/WEB-INF/");
102     }
103
104     /**
105      * Creates new WebApplicationResourceLocator with default lookup policy including user
106      * home directory, current directory and CLASSPATH.
107      */
108     public WebApplicationResourceLocator(ServletContext JavaDoc context) {
109         this();
110         setServletContext(context);
111     }
112
113     /**
114      * Sets the ServletContext used to locate resources.
115      */
116     public void setServletContext(ServletContext JavaDoc servletContext) {
117         this.context = servletContext;
118     }
119
120     /**
121      * Gets the ServletContext used to locate resources.
122      */
123     public ServletContext JavaDoc getServletContext() {
124         return this.context;
125     }
126
127     /**
128      * Looks for resources relative to /WEB-INF/ directory or any extra context paths
129      * configured. Internal ServletContext is used to find resources.
130      */
131     public URL JavaDoc findResource(String JavaDoc location) {
132         if (!additionalContextPaths.isEmpty() && getServletContext() != null) {
133
134             Iterator JavaDoc cpi = this.additionalContextPaths.iterator();
135             while (cpi.hasNext()) {
136                 String JavaDoc fullName = cpi.next() + "/" + location;
137                 logObj.debug("searching for: " + fullName);
138                 try {
139                     URL JavaDoc url = getServletContext().getResource(fullName);
140                     if (url != null) {
141                         return url;
142                     }
143                 }
144                 catch (MalformedURLException JavaDoc ex) {
145                     // ignoring
146 logObj.debug("Malformed URL, ignoring.", ex);
147                 }
148             }
149         }
150
151         return super.findResource(location);
152     }
153
154     /**
155      * Override ResourceLocator.addFilesystemPath(String) to intercept context paths
156      * starting with "/WEB-INF/" to place in additionalContextPaths.
157      */
158     public void addFilesystemPath(String JavaDoc path) {
159         if (path != null) {
160             if (path.startsWith("/WEB-INF/")) {
161                 this.additionalContextPaths.add(path);
162             }
163             else {
164                 super.addFilesystemPath(path);
165             }
166         }
167         else {
168             throw new IllegalArgumentException JavaDoc("Path must not be null.");
169         }
170     }
171 }
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