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
018package org.apache.commons.configuration;
019
020import java.io.File;
021import java.io.InputStream;
022import java.io.OutputStream;
023import java.io.Reader;
024import java.io.Writer;
025import java.net.URL;
026
027import 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 $Id: FileConfiguration.java 1209883 2011-12-03 10:56:57Z oheger $
034 * @since 1.0-rc2
035 */
036public 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} 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()} or {@code setURL()} 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} the base path
188     * will be {@code file:/temp/}). If the base path was explicitly set
189     * using {@code setBasePath()}, 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()} and
199     * {@code setFileName()} 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}), 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 automatically saving of modified properties to the disk.
238     *
239     * @param autoSave {@code true} to enable, {@code false} 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} if auto-saving is enabled, {@code false} 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}