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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.configuration;
19  
20  import java.io.File;
21  import java.io.InputStream;
22  import java.io.OutputStream;
23  import java.io.Reader;
24  import java.io.Writer;
25  import java.net.URL;
26  
27  import org.apache.commons.configuration.reloading.ReloadingStrategy;
28  
29  /**
30   * A persistent configuration loaded and saved to a file.
31   *
32   * @author Emmanuel Bourg
33   * @version $Id: FileConfiguration.java 1209883 2011-12-03 10:56:57Z oheger $
34   * @since 1.0-rc2
35   */
36  public interface FileConfiguration extends Configuration
37  {
38      /**
39       * Load the configuration from the underlying URL. If the URL is not
40       * specified, it attempts to locate the specified file name.
41       *
42       * @throws ConfigurationException if an error occurs during the load operation
43       */
44      void load() throws ConfigurationException;
45  
46      /**
47       * Locate the specified file and load the configuration.
48       *
49       * @param fileName the name of the file loaded
50       *
51       * @throws ConfigurationException if an error occurs during the load operation
52       */
53      void load(String fileName) throws ConfigurationException;
54  
55      /**
56       * Load the configuration from the specified file.
57       *
58       * @param file the loaded file
59       *
60       * @throws ConfigurationException if an error occurs during the load operation
61       */
62      void load(File file) throws ConfigurationException;
63  
64      /**
65       * Load the configuration from the specified URL.
66       *
67       * @param url the URL of the file loaded
68       *
69       * @throws ConfigurationException if an error occurs during the load operation
70       */
71      void load(URL url) throws ConfigurationException;
72  
73      /**
74       * Load the configuration from the specified stream, using the encoding
75       * returned by {@link #getEncoding()}.
76       *
77       * @param in the input stream
78       *
79       * @throws ConfigurationException if an error occurs during the load operation
80       */
81      void load(InputStream in) throws ConfigurationException;
82  
83      /**
84       * Load the configuration from the specified stream, using the specified
85       * encoding. If the encoding is null the default encoding is used.
86       *
87       * @param in the input stream
88       * @param encoding the encoding used. {@code null} to use the default encoding
89       *
90       * @throws ConfigurationException if an error occurs during the load operation
91       */
92      void load(InputStream in, String encoding) throws ConfigurationException;
93  
94      /**
95       * Load the configuration from the specified reader.
96       *
97       * @param in the reader
98       *
99       * @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 }