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
9
* http://www.apache.org/licenses/LICENSE-2.0
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.
18
package org.apache.commons.configuration;
20
import java.math.BigDecimal;
21
import java.math.BigInteger;
22
import java.util.Iterator;
23
import java.util.List;
24
import java.util.Properties;
27
* <p>The main Configuration interface.</p>
28
* <p>This interface allows accessing and manipulating a configuration object.
29
* The major part of the methods defined in this interface deals with accessing
30
* properties of various data types. There is a generic {@code getProperty()}
31
* method, which returns the value of the queried property in its raw data
32
* type. Other getter methods try to convert this raw data type into a specific
33
* data type. If this fails, a {@code ConversionException} will be thrown.</p>
34
* <p>For most of the property getter methods an overloaded version exists that
35
* allows to specify a default value, which will be returned if the queried
36
* property cannot be found in the configuration. The behavior of the methods
37
* that do not take a default value in case of a missing property is not defined
38
* by this interface and depends on a concrete implementation. E.g. the
39
* {@link AbstractConfiguration} class, which is the base class
40
* of most configuration implementations provided by this package, per default
41
* returns <b>null</b> if a property is not found, but provides the
42
* {@link AbstractConfiguration#setThrowExceptionOnMissing(boolean)
43
* setThrowExceptionOnMissing()}
44
* method, with which it can be configured to throw a {@code NoSuchElementException}
45
* exception in that case. (Note that getter methods for primitive types in
46
* {@code AbstractConfiguration} always throw an exception for missing
47
* properties because there is no way of overloading the return value.)</p>
48
* <p>With the {@code addProperty()} and {@code setProperty()} methods
49
* new properties can be added to a configuration or the values of properties
50
* can be changed. With {@code clearProperty()} a property can be removed.
51
* Other methods allow to iterate over the contained properties or to create
52
* a subset configuration.</p>
54
* @author Commons Configuration team
55
* @version $Id: Configuration.java 1204078 2011-11-19 21:28:49Z oheger $
57
public interface Configuration
60
* Return a decorator Configuration containing every key from the current
61
* Configuration that starts with the specified prefix. The prefix is
62
* removed from the keys in the subset. For example, if the configuration
63
* contains the following properties:
67
* prefix.string = Apache
69
* prefix = Jakarta</pre>
71
* the Configuration returned by {@code subset("prefix")} will contain
79
* (The key for the value "Jakarta" is an empty string)
81
* Since the subset is a decorator and not a modified copy of the initial
82
* Configuration, any change made to the subset is available to the
83
* Configuration, and reciprocally.
85
* @param prefix The prefix used to select the properties.
86
* @return a subset configuration
88
* @see SubsetConfiguration
90
Configuration subset(String prefix);
93
* Check if the configuration is empty.
95
* @return {@code true} if the configuration contains no property,
96
* {@code false} otherwise.
101
* Check if the configuration contains the specified key.
103
* @param key the key whose presence in this configuration is to be tested
105
* @return {@code true} if the configuration contains a value for this
106
* key, {@code false} otherwise
108
boolean containsKey(String key);
111
* Add a property to the configuration. If it already exists then the value
112
* stated here will be added to the configuration entry. For example, if
115
* <pre>resource.loader = file</pre>
117
* is already present in the configuration and you call
119
* <pre>addProperty("resource.loader", "classpath")</pre>
121
* Then you will end up with a List like the following:
123
* <pre>["file", "classpath"]</pre>
125
* @param key The key to add the property to.
126
* @param value The value to add.
128
void addProperty(String key, Object value);
131
* Set a property, this will replace any previously set values. Set values
132
* is implicitly a call to clearProperty(key), addProperty(key, value).
134
* @param key The key of the property to change
135
* @param value The new value
137
void setProperty(String key, Object value);
140
* Remove a property from the configuration.
142
* @param key the key to remove along with corresponding value.
144
void clearProperty(String key);
147
* Remove all properties from the configuration.
152
* Gets a property from the configuration. This is the most basic get
153
* method for retrieving values of properties. In a typical implementation
154
* of the {@code Configuration} interface the other get methods (that
155
* return specific data types) will internally make use of this method. On
156
* this level variable substitution is not yet performed. The returned
157
* object is an internal representation of the property value for the passed
158
* in key. It is owned by the {@code Configuration} object. So a caller
159
* should not modify this object. It cannot be guaranteed that this object
160
* will stay constant over time (i.e. further update operations on the
161
* configuration may change its internal state).
163
* @param key property to retrieve
164
* @return the value to which this configuration maps the specified key, or
165
* null if the configuration contains no mapping for this key.
167
Object getProperty(String key);
170
* Get the list of the keys contained in the configuration that match the
171
* specified prefix. For instance, if the configuration contains the
172
* following keys:<br>
173
* {@code db.user, db.pwd, db.url, window.xpos, window.ypos},<br>
174
* an invocation of {@code getKeys("db");}<br>
175
* will return the keys below:<br>
176
* {@code db.user, db.pwd, db.url}.<br>
177
* Note that the prefix itself is included in the result set if there is a
178
* matching key. The exact behavior - how the prefix is actually
179
* interpreted - depends on a concrete implementation.
181
* @param prefix The prefix to test against.
182
* @return An Iterator of keys that match the prefix.
185
Iterator<String> getKeys(String prefix);
188
* Get the list of the keys contained in the configuration. The returned
189
* iterator can be used to obtain all defined keys. Note that the exact
190
* behavior of the iterator's {@code remove()} method is specific to
191
* a concrete implementation. It <em>may</em> remove the corresponding
192
* property from the configuration, but this is not guaranteed. In any case
193
* it is no replacement for calling
194
* {@link #clearProperty(String)} for this property. So it is
195
* highly recommended to avoid using the iterator's {@code remove()}
198
* @return An Iterator.
200
Iterator<String> getKeys();
203
* Get a list of properties associated with the given configuration key.
204
* This method expects the given key to have an arbitrary number of String
205
* values, each of which is of the form {code key=value}. These
206
* strings are split at the equals sign, and the key parts will become
207
* keys of the returned {@code Properties} object, the value parts
210
* @param key The configuration key.
211
* @return The associated properties if key is found.
213
* @throws ConversionException is thrown if the key maps to an
214
* object that is not a String/List.
216
* @throws IllegalArgumentException if one of the tokens is
217
* malformed (does not contain an equals sign).
219
Properties getProperties(String key);
222
* Get a boolean associated with the given configuration key.
224
* @param key The configuration key.
225
* @return The associated boolean.
227
* @throws ConversionException is thrown if the key maps to an
228
* object that is not a Boolean.
230
boolean getBoolean(String key);
233
* Get a boolean associated with the given configuration key.
234
* If the key doesn't map to an existing object, the default value
237
* @param key The configuration key.
238
* @param defaultValue The default value.
239
* @return The associated boolean.
241
* @throws ConversionException is thrown if the key maps to an
242
* object that is not a Boolean.
244
boolean getBoolean(String key, boolean defaultValue);
247
* Get a {@link Boolean} associated with the given configuration key.
249
* @param key The configuration key.
250
* @param defaultValue The default value.
251
* @return The associated boolean if key is found and has valid
252
* format, default value otherwise.
254
* @throws ConversionException is thrown if the key maps to an
255
* object that is not a Boolean.
257
Boolean getBoolean(String key, Boolean defaultValue);
260
* Get a byte associated with the given configuration key.
262
* @param key The configuration key.
263
* @return The associated byte.
265
* @throws ConversionException is thrown if the key maps to an
266
* object that is not a Byte.
268
byte getByte(String key);
271
* Get a byte associated with the given configuration key.
272
* If the key doesn't map to an existing object, the default value
275
* @param key The configuration key.
276
* @param defaultValue The default value.
277
* @return The associated byte.
279
* @throws ConversionException is thrown if the key maps to an
280
* object that is not a Byte.
282
byte getByte(String key, byte defaultValue);
285
* Get a {@link Byte} associated with the given configuration key.
287
* @param key The configuration key.
288
* @param defaultValue The default value.
289
* @return The associated byte if key is found and has valid format, default
292
* @throws ConversionException is thrown if the key maps to an object that
295
Byte getByte(String key, Byte defaultValue);
298
* Get a double associated with the given configuration key.
300
* @param key The configuration key.
301
* @return The associated double.
303
* @throws ConversionException is thrown if the key maps to an
304
* object that is not a Double.
306
double getDouble(String key);
309
* Get a double associated with the given configuration key.
310
* If the key doesn't map to an existing object, the default value
313
* @param key The configuration key.
314
* @param defaultValue The default value.
315
* @return The associated double.
317
* @throws ConversionException is thrown if the key maps to an
318
* object that is not a Double.
320
double getDouble(String key, double defaultValue);
323
* Get a {@link Double} associated with the given configuration key.
325
* @param key The configuration key.
326
* @param defaultValue The default value.
327
* @return The associated double if key is found and has valid
328
* format, default value otherwise.
330
* @throws ConversionException is thrown if the key maps to an
331
* object that is not a Double.
333
Double getDouble(String key, Double defaultValue);
336
* Get a float associated with the given configuration key.
338
* @param key The configuration key.
339
* @return The associated float.
340
* @throws ConversionException is thrown if the key maps to an
341
* object that is not a Float.
343
float getFloat(String key);
346
* Get a float associated with the given configuration key.
347
* If the key doesn't map to an existing object, the default value
350
* @param key The configuration key.
351
* @param defaultValue The default value.
352
* @return The associated float.
354
* @throws ConversionException is thrown if the key maps to an
355
* object that is not a Float.
357
float getFloat(String key, float defaultValue);
360
* Get a {@link Float} associated with the given configuration key.
361
* If the key doesn't map to an existing object, the default value
364
* @param key The configuration key.
365
* @param defaultValue The default value.
366
* @return The associated float if key is found and has valid
367
* format, default value otherwise.
369
* @throws ConversionException is thrown if the key maps to an
370
* object that is not a Float.
372
Float getFloat(String key, Float defaultValue);
375
* Get a int associated with the given configuration key.
377
* @param key The configuration key.
378
* @return The associated int.
380
* @throws ConversionException is thrown if the key maps to an
381
* object that is not a Integer.
383
int getInt(String key);
386
* Get a int associated with the given configuration key.
387
* If the key doesn't map to an existing object, the default value
390
* @param key The configuration key.
391
* @param defaultValue The default value.
392
* @return The associated int.
394
* @throws ConversionException is thrown if the key maps to an
395
* object that is not a Integer.
397
int getInt(String key, int defaultValue);
400
* Get an {@link Integer} associated with the given configuration key.
401
* If the key doesn't map to an existing object, the default value
404
* @param key The configuration key.
405
* @param defaultValue The default value.
406
* @return The associated int if key is found and has valid format, default
409
* @throws ConversionException is thrown if the key maps to an object that
412
Integer getInteger(String key, Integer defaultValue);
415
* Get a long associated with the given configuration key.
417
* @param key The configuration key.
418
* @return The associated long.
420
* @throws ConversionException is thrown if the key maps to an
421
* object that is not a Long.
423
long getLong(String key);
426
* Get a long associated with the given configuration key.
427
* If the key doesn't map to an existing object, the default value
430
* @param key The configuration key.
431
* @param defaultValue The default value.
432
* @return The associated long.
434
* @throws ConversionException is thrown if the key maps to an
435
* object that is not a Long.
437
long getLong(String key, long defaultValue);
440
* Get a {@link Long} associated with the given configuration key.
441
* If the key doesn't map to an existing object, the default value
444
* @param key The configuration key.
445
* @param defaultValue The default value.
446
* @return The associated long if key is found and has valid
447
* format, default value otherwise.
449
* @throws ConversionException is thrown if the key maps to an
450
* object that is not a Long.
452
Long getLong(String key, Long defaultValue);
455
* Get a short associated with the given configuration key.
457
* @param key The configuration key.
458
* @return The associated short.
460
* @throws ConversionException is thrown if the key maps to an
461
* object that is not a Short.
463
short getShort(String key);
466
* Get a short associated with the given configuration key.
468
* @param key The configuration key.
469
* @param defaultValue The default value.
470
* @return The associated short.
472
* @throws ConversionException is thrown if the key maps to an
473
* object that is not a Short.
475
short getShort(String key, short defaultValue);
478
* Get a {@link Short} associated with the given configuration key.
479
* If the key doesn't map to an existing object, the default value
482
* @param key The configuration key.
483
* @param defaultValue The default value.
484
* @return The associated short if key is found and has valid
485
* format, default value otherwise.
487
* @throws ConversionException is thrown if the key maps to an
488
* object that is not a Short.
490
Short getShort(String key, Short defaultValue);
493
* Get a {@link BigDecimal} associated with the given configuration key.
495
* @param key The configuration key.
496
* @return The associated BigDecimal if key is found and has valid format
498
BigDecimal getBigDecimal(String key);
501
* Get a {@link BigDecimal} associated with the given configuration key.
502
* If the key doesn't map to an existing object, the default value
505
* @param key The configuration key.
506
* @param defaultValue The default value.
508
* @return The associated BigDecimal if key is found and has valid
509
* format, default value otherwise.
511
BigDecimal getBigDecimal(String key, BigDecimal defaultValue);
514
* Get a {@link BigInteger} associated with the given configuration key.
516
* @param key The configuration key.
518
* @return The associated BigInteger if key is found and has valid format
520
BigInteger getBigInteger(String key);
523
* Get a {@link BigInteger} associated with the given configuration key.
524
* If the key doesn't map to an existing object, the default value
527
* @param key The configuration key.
528
* @param defaultValue The default value.
530
* @return The associated BigInteger if key is found and has valid
531
* format, default value otherwise.
533
BigInteger getBigInteger(String key, BigInteger defaultValue);
536
* Get a string associated with the given configuration key.
538
* @param key The configuration key.
539
* @return The associated string.
541
* @throws ConversionException is thrown if the key maps to an object that
544
String getString(String key);
547
* Get a string associated with the given configuration key.
548
* If the key doesn't map to an existing object, the default value
551
* @param key The configuration key.
552
* @param defaultValue The default value.
553
* @return The associated string if key is found and has valid
554
* format, default value otherwise.
556
* @throws ConversionException is thrown if the key maps to an object that
559
String getString(String key, String defaultValue);
562
* Get an array of strings associated with the given configuration key.
563
* If the key doesn't map to an existing object an empty array is returned
565
* @param key The configuration key.
566
* @return The associated string array if key is found.
568
* @throws ConversionException is thrown if the key maps to an
569
* object that is not a String/List of Strings.
571
String[] getStringArray(String key);
574
* Get a List of strings associated with the given configuration key.
575
* If the key doesn't map to an existing object an empty List is returned.
577
* @param key The configuration key.
578
* @return The associated List.
580
* @throws ConversionException is thrown if the key maps to an
581
* object that is not a List.
583
List<Object> getList(String key);
586
* Get a List of strings associated with the given configuration key.
587
* If the key doesn't map to an existing object, the default value
590
* @param key The configuration key.
591
* @param defaultValue The default value.
592
* @return The associated List of strings.
594
* @throws ConversionException is thrown if the key maps to an
595
* object that is not a List.
597
List<Object> getList(String key, List<Object> defaultValue);
added
removed
src/main/java/org/apache/commons/configuration/Configuration.java
