001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    package org.apache.commons.configuration;
019    
020    import java.net.URL;
021    import java.io.InputStream;
022    import java.io.Reader;
023    import java.io.OutputStream;
024    import java.io.Writer;
025    import java.io.File;
026    
027    import org.apache.commons.configuration.reloading.ReloadingStrategy;
028    
029    /**
030     * A persistent configuration loaded and saved to a file.
031     *
032     * @author Emmanuel Bourg
033     * @version $Revision: 529194 $, $Date: 2007-04-16 12:40:42 +0200 (Mo, 16 Apr 2007) $
034     * @since 1.0-rc2
035     */
036    public interface FileConfiguration extends Configuration
037    {
038        /**
039         * Load the configuration from the underlying URL. If the URL is not
040         * specified, it attempts to locate the specified file name.
041         *
042         * @throws ConfigurationException if an error occurs during the load operation
043         */
044        void load() throws ConfigurationException;
045    
046        /**
047         * Locate the specified file and load the configuration.
048         *
049         * @param fileName the name of the file loaded
050         *
051         * @throws ConfigurationException if an error occurs during the load operation
052         */
053        void load(String fileName) throws ConfigurationException;
054    
055        /**
056         * Load the configuration from the specified file.
057         *
058         * @param file the loaded file
059         *
060         * @throws ConfigurationException if an error occurs during the load operation
061         */
062        void load(File file) throws ConfigurationException;
063    
064        /**
065         * Load the configuration from the specified URL.
066         *
067         * @param url the URL of the file loaded
068         *
069         * @throws ConfigurationException if an error occurs during the load operation
070         */
071        void load(URL url) throws ConfigurationException;
072    
073        /**
074         * Load the configuration from the specified stream, using the encoding
075         * returned by {@link #getEncoding()}.
076         *
077         * @param in the input stream
078         *
079         * @throws ConfigurationException if an error occurs during the load operation
080         */
081        void load(InputStream in) throws ConfigurationException;
082    
083        /**
084         * Load the configuration from the specified stream, using the specified
085         * encoding. If the encoding is null the default encoding is used.
086         *
087         * @param in the input stream
088         * @param encoding the encoding used. <code>null</code> to use the default encoding
089         *
090         * @throws ConfigurationException if an error occurs during the load operation
091         */
092        void load(InputStream in, String encoding) throws ConfigurationException;
093    
094        /**
095         * Load the configuration from the specified reader.
096         *
097         * @param in the reader
098         *
099         * @throws ConfigurationException if an error occurs during the load operation
100         */
101        void load(Reader in) throws ConfigurationException;
102    
103        /**
104         * Save the configuration.
105         *
106         * @throws ConfigurationException if an error occurs during the save operation
107         */
108        void save() throws ConfigurationException;
109    
110        /**
111         * Save the configuration to the specified file.
112         *
113         * @param fileName the name of the file to be saved
114         *
115         * @throws ConfigurationException if an error occurs during the save operation
116         */
117        void save(String fileName) throws ConfigurationException;
118    
119        /**
120         * Save the configuration to the specified file.
121         *
122         * @param file specifies the file to be saved
123         *
124         * @throws ConfigurationException if an error occurs during the save operation
125         */
126        void save(File file) throws ConfigurationException;
127    
128        /**
129         * Save the configuration to the specified URL.
130         *
131         * @param url the URL
132         *
133         * @throws ConfigurationException if an error occurs during the save operation
134         */
135        void save(URL url) throws ConfigurationException;
136    
137        /**
138         * Save the configuration to the specified stream, using the encoding
139         * returned by {@link #getEncoding()}.
140         *
141         * @param out the output stream
142         *
143         * @throws ConfigurationException if an error occurs during the save operation
144         */
145        void save(OutputStream out) throws ConfigurationException;
146    
147        /**
148         * Save the configuration to the specified stream, using the specified
149         * encoding. If the encoding is null the default encoding is used.
150         *
151         * @param out the output stream
152         * @param encoding the encoding to be used
153         * @throws ConfigurationException if an error occurs during the save operation
154         */
155        void save(OutputStream out, String encoding) throws ConfigurationException;
156    
157        /**
158         * Save the configuration to the specified writer.
159         *
160         * @param out the writer
161         *
162         * @throws ConfigurationException if an error occurs during the save operation
163         */
164        void save(Writer out) throws ConfigurationException;
165    
166        /**
167         * Return the name of the file.
168         *
169         * @return the file name
170         */
171        String getFileName();
172    
173        /**
174         * Set the name of the file.
175         *
176         * @param fileName the name of the file
177         */
178        void setFileName(String fileName);
179    
180        /**
181         * Returns the base path. One way to specify the location of a configuration
182         * source is by setting its base path and its file name. This method returns
183         * this base path. The concrete value returned by this method depends on the
184         * way the location of the configuration file was set. If methods like
185         * <code>setFile()</code> or <code>setURL()</code> were used, the base
186         * path typically points to the parent directory of the configuration file
187         * (e.g. for the URL <code>file:/temp/test.properties</code> the base path
188         * will be <code>file:/temp/</code>). If the base path was explictly set
189         * using <code>setBasePath()</code>, this method will return the exact
190         * value specified here without further modifications.
191         *
192         * @return the base path
193         * @see AbstractFileConfiguration#setBasePath(String)
194         */
195        String getBasePath();
196    
197        /**
198         * Sets the base path. The methods <code>setBasePath()</code> and
199         * <code>setFileName()</code> can be used together to specify the location
200         * of the configuration file to be loaded. If relative file names are to
201         * be resolved (e.g. for the include files supported by
202         * <code>PropertiesConfiguration</code>), this base path will be used.
203         *
204         * @param basePath the base path.
205         */
206        void setBasePath(String basePath);
207    
208        /**
209         * Return the file where the configuration is stored.
210         *
211         * @return the configuration file
212         */
213        File getFile();
214    
215        /**
216         * Set the file where the configuration is stored.
217         *
218         * @param file the file
219         */
220        void setFile(File file);
221    
222        /**
223         * Return the URL where the configuration is stored.
224         *
225         * @return the URL of the configuration
226         */
227        URL getURL();
228    
229        /**
230         * The URL where the configuration is stored.
231         *
232         * @param url the URL
233         */
234        void setURL(URL url);
235    
236        /**
237         * Enable or disable the automatical saving of modified properties to the disk.
238         *
239         * @param autoSave <code>true</code> to enable, <code>false</code> to disable
240         * @since 1.1
241         */
242        void setAutoSave(boolean autoSave);
243    
244        /**
245         * Tells if properties are automatically saved to the disk.
246         *
247         * @return <code>true</code> if auto-saving is enabled, <code>false</code> otherwise
248         * @since 1.1
249         */
250        boolean isAutoSave();
251    
252        /**
253         * Return the reloading strategy.
254         *
255         * @return the reloading strategy currently used
256         * @since 1.1
257         */
258        ReloadingStrategy getReloadingStrategy();
259    
260        /**
261         * Set the reloading strategy.
262         *
263         * @param strategy the reloading strategy to use
264         * @since 1.1
265         */
266        void setReloadingStrategy(ReloadingStrategy strategy);
267    
268        /**
269         * Reload the configuration.
270         *
271         * @since 1.1
272         */
273        void reload();
274    
275        /**
276         * Return the encoding used to store the configuration file. If the value
277         * is null the default encoding is used.
278         *
279         * @return the current encoding
280         * @since 1.1
281         */
282        String getEncoding();
283    
284        /**
285         * Set the encoding used to store the configuration file. Set the encoding
286         * to null to use the default encoding.
287         *
288         * @param encoding the encoding to use
289         * @since 1.1
290         */
291        void setEncoding(String encoding);
292    
293    }