001 /*
002 * $Id: WebappPropertyResources.java 348371 2005-11-23 04:56:51Z niallp $
003 * $Revision: 348371 $
004 * $Date: 2005-11-23 04:56:51 +0000 (Wed, 23 Nov 2005) $
005 *
006 * ====================================================================
007 *
008 * Copyright 2003-2005 The Apache Software Foundation
009 *
010 * Licensed under the Apache License, Version 2.0 (the "License");
011 * you may not use this file except in compliance with the License.
012 * You may obtain a copy of the License at
013 *
014 * http://www.apache.org/licenses/LICENSE-2.0
015 *
016 * Unless required by applicable law or agreed to in writing, software
017 * distributed under the License is distributed on an "AS IS" BASIS,
018 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
019 * See the License for the specific language governing permissions and
020 * limitations under the License.
021 *
022 */
023
024 package org.apache.commons.resources.impl;
025
026 import java.io.FileNotFoundException;
027 import java.io.IOException;
028 import java.io.InputStream;
029 import java.util.Locale;
030 import java.util.Map;
031 import java.util.Properties;
032
033 import javax.servlet.ServletContext;
034
035 import org.apache.commons.logging.Log;
036 import org.apache.commons.logging.LogFactory;
037
038 /**
039 * <p>Concrete implementation of {@link org.apache.commons.resources.Resources} that wraps a family
040 * (one per <code>Locale</code> of properties files that share a base
041 * context-relative path for servlet context resources, and have
042 * name suffixes reflecting the <code>Locale</code> for which
043 * the document's messages apply. Resources are looked up in a hierarchy
044 * of properties files in a manner identical to that performed by
045 * <code>java.util.ResourceBundle.getBundle().</code>.</p>
046 *
047 * <p>The base resource path passed to our constructor must contain the
048 * context-relative base name of the properties file family.
049 * For example, if the base path is passed as
050 * <code>http://localhost/foo/Bar</code>, the resources for the
051 * <code>en_US</code> Locale would be stored under URL
052 * <code>http://localhost/foo/Bar_en_US.properties</code>, and the default
053 * resources would be stored in
054 * <code>http://localhost/foo/Bar.properties</code>.</p>
055 */
056 public class WebappPropertyResources extends CollectionResourcesBase {
057
058 /**
059 * <p>The <code>Log</code> instance for this class.</p>
060 */
061 private transient Log log =
062 LogFactory.getLog(WebappPropertyResources.class);
063
064 // ----------------------------------------------------------- Constructors
065
066
067 /**
068 * <p>Create a new {@link org.apache.commons.resources.Resources} instance with the specified
069 * logical name and base resource URL.</p>
070 *
071 * @param name Logical name of the new instance
072 * @param base Base URL of the family of properties files that contain
073 * the resource keys and values
074 * @param servletContext the <code>ServletContext</code> instance
075 * to use for resolving resource references
076 */
077 public WebappPropertyResources(String name, String base,
078 ServletContext servletContext) {
079
080 super(name, base);
081 this.servletContext = servletContext;
082
083 }
084
085
086 // ----------------------------------------------------- Instance Variables
087
088
089 /**
090 * <p>The <code>ServletContext</code> instance for resolving
091 * our resources references.</p>
092 */
093 private ServletContext servletContext = null;
094
095
096 // ------------------------------------------------------ Protected Methods
097
098
099 /**
100 * <p>Return a <code>Map</code> containing the name-value mappings for
101 * the specified base URL and requested <code>Locale</code>, if there
102 * are any. If there are no defined mappings for the specified
103 * <code>Locale</code>, return an empty <code>Map</code> instead.</p>
104 *
105 * <p>Concrete subclasses must override this method to perform the
106 * appropriate lookup. A typical implementation will construct an
107 * absolute URL based on the specified base URL and <code>Locale</code>,
108 * retrieve the specified resource file (if any), and parse it into
109 * a <code>Map</code> structure.</p>
110 *
111 * <p>Caching of previously retrieved <code>Map</code>s (if any) should
112 * be performed by callers of this method. Therefore, this method should
113 * always attempt to retrieve the specified resource and load it
114 * appropriately.</p>
115 *
116 * @param baseUrl Base URL of the resource files for this {@link org.apache.commons.resources.Resources}
117 * instance
118 * @param locale <code>Locale</code> for which name-value mappings
119 * are requested
120 * @return A name-value Map for the specified URL and locale.
121 */
122 protected Map getLocaleMap(String baseUrl, Locale locale) {
123
124 if (getLog().isDebugEnabled()) {
125 getLog().debug("Loading locale '" + locale + "' resources from base '" +
126 baseUrl + "'");
127 }
128
129 Properties props = new Properties();
130 String name = baseUrl.replace('.', '/');
131 name += getLocaleSuffix(locale) + ".properties";
132
133 InputStream stream = null;
134
135 try {
136
137 // Open an input stream to the URL for this locale (if any)
138 if (getLog().isTraceEnabled()) {
139 getLog().trace("Complete path is '" + name + "'");
140 }
141 try{
142 stream = servletContext.getResourceAsStream(name);
143 }
144 catch(Exception e){
145 // not found
146 // try ContextClassLoader
147 }
148 if (stream == null){
149
150 ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
151 if (classLoader == null) {
152 classLoader = this.getClass().getClassLoader();
153 }
154 stream = classLoader.getResourceAsStream(name);
155 }
156
157 // Parse the input stream and populate the name-value mappings map
158 if (stream != null) {
159 if (getLog().isTraceEnabled()) {
160 getLog().trace("Parsing input resource");
161 }
162 props.load(stream);
163 }
164
165 } catch (FileNotFoundException e) {
166
167 // Log and swallow this exception
168 if (getLog().isDebugEnabled()) {
169 getLog().debug("No resources for locale '" + locale +
170 "' from base '" + baseUrl + "'");
171 }
172 props.clear();
173
174 } catch (IOException e) {
175
176 getLog().warn("IOException loading locale '" + locale +
177 "' from base '" + baseUrl + "'", e);
178 props.clear();
179
180 } finally {
181
182 // Close the input stream that was opened earlier
183 if (stream != null) {
184 try {
185 stream.close();
186 } catch (IOException e) {
187 getLog().error("Error closing stream.", e);
188 }
189 stream = null;
190 }
191
192 }
193
194 // Return the populated (or empty) properties
195 return (props);
196
197 }
198
199 /**
200 * Accessor method for Log instance.
201 *
202 * The Log instance variable is transient and
203 * accessing it through this method ensures it
204 * is re-initialized when this instance is
205 * de-serialized.
206 *
207 * @return The Log instance.
208 */
209 private Log getLog() {
210 if (log == null) {
211 log = LogFactory.getLog(WebappPropertyResources.class);
212 }
213 return log;
214 }
215
216 }