Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
CombinedConfiguration |
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| 1.8461538461538463;1,846 | ||||
CombinedConfiguration$ConfigData |
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| 1.8461538461538463;1,846 |
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 | package org.apache.commons.configuration; | |
18 | ||
19 | import java.util.ArrayList; | |
20 | import java.util.Collection; | |
21 | import java.util.HashMap; | |
22 | import java.util.Iterator; | |
23 | import java.util.List; | |
24 | import java.util.Map; | |
25 | import java.util.Set; | |
26 | ||
27 | import org.apache.commons.configuration.event.ConfigurationEvent; | |
28 | import org.apache.commons.configuration.event.ConfigurationListener; | |
29 | import org.apache.commons.configuration.tree.ConfigurationNode; | |
30 | import org.apache.commons.configuration.tree.DefaultConfigurationKey; | |
31 | import org.apache.commons.configuration.tree.DefaultConfigurationNode; | |
32 | import org.apache.commons.configuration.tree.DefaultExpressionEngine; | |
33 | import org.apache.commons.configuration.tree.NodeCombiner; | |
34 | import org.apache.commons.configuration.tree.UnionCombiner; | |
35 | import org.apache.commons.configuration.tree.ViewNode; | |
36 | ||
37 | /** | |
38 | * <p> | |
39 | * A hierarchical composite configuration class. | |
40 | * </p> | |
41 | * <p> | |
42 | * This class maintains a list of configuration objects, which can be added | |
43 | * using the divers <code>addConfiguration()</code> methods. After that the | |
44 | * configurations can be accessed either by name (if one was provided when the | |
45 | * configuration was added) or by index. For the whole set of managed | |
46 | * configurations a logical node structure is constructed. For this purpose a | |
47 | * <code>{@link org.apache.commons.configuration.tree.NodeCombiner NodeCombiner}</code> | |
48 | * object can be set. This makes it possible to specify different algorithms for | |
49 | * the combination process. | |
50 | * </p> | |
51 | * <p> | |
52 | * The big advantage of this class is that it creates a truely hierarchical | |
53 | * structure of all the properties stored in the contained configurations - even | |
54 | * if some of them are no hierarchical configurations per se. So all enhanced | |
55 | * features provided by a hierarchical configuration (e.g. choosing an | |
56 | * expression engine) are applicable. | |
57 | * </p> | |
58 | * <p> | |
59 | * The class works by registering itself as an event listener add all added | |
60 | * configurations. So it gets notified whenever one of these configurations is | |
61 | * changed and can invalidate its internal node structure. The next time a | |
62 | * property is accessed the node structure will be re-constructed using the | |
63 | * current state of the managed configurations. Node that, depending on the used | |
64 | * <code>NodeCombiner</code>, this may be a complex operation. | |
65 | * </p> | |
66 | * <p> | |
67 | * It is not strictly forbidden to manipulate a | |
68 | * <code>CombinedConfiguration</code> directly, but the results may be | |
69 | * unpredictable. For instance some node combiners use special view nodes for | |
70 | * linking parts of the original configurations' data together. If new | |
71 | * properties are added to such a special node, they do not belong to any of the | |
72 | * managed configurations and thus hang in the air. It is also possible that | |
73 | * direct updates on a <code>CombinedConfiguration</code> are incompatible | |
74 | * with the used node combiner (e.g. if the | |
75 | * <code>{@link org.apache.commons.configuration.tree.OverrideCombiner OverrideCombiner}</code> | |
76 | * is used and properties are removed the resulting node structure may be | |
77 | * incorrect because some properties that were hidden by the removed properties | |
78 | * are not visible). So it is recommended to perform updates only on the managed | |
79 | * configurations. | |
80 | * </p> | |
81 | * <p> | |
82 | * Whenever the node structure of a <code>CombinedConfiguration</code> becomes | |
83 | * invalid (either because one of the contained configurations was modified or | |
84 | * because the <code>invalidate()</code> method was directly called) an event | |
85 | * is generated. So this can be detected by interested event listeners. This | |
86 | * also makes it possible to add a combined configuration into another one. | |
87 | * </p> | |
88 | * <p> | |
89 | * Implementation note: Adding and removing configurations to and from a | |
90 | * combined configuration is not thread-safe. If a combined configuration is | |
91 | * manipulated by multiple threads, the developer has to take care about | |
92 | * properly synchronization. | |
93 | * </p> | |
94 | * | |
95 | * @author <a | |
96 | * href="http://jakarta.apache.org/commons/configuration/team-list.html">Commons | |
97 | * Configuration team</a> | |
98 | * @since 1.3 | |
99 | * @version $Id: CombinedConfiguration.java 439648 2006-09-02 20:42:10Z oheger $ | |
100 | */ | |
101 | 11 | public class CombinedConfiguration extends HierarchicalConfiguration implements |
102 | ConfigurationListener, Cloneable | |
103 | { | |
104 | /** | |
105 | * Constant for the invalidate event that is fired when the internal node | |
106 | * structure becomes invalid. | |
107 | */ | |
108 | public static final int EVENT_COMBINED_INVALIDATE = 40; | |
109 | ||
110 | /** | |
111 | * The serial version ID. | |
112 | */ | |
113 | private static final long serialVersionUID = 8338574525528692307L; | |
114 | ||
115 | /** Constant for the expression engine for parsing the at path. */ | |
116 | 6 | private static final DefaultExpressionEngine AT_ENGINE = new DefaultExpressionEngine(); |
117 | ||
118 | /** Constant for the default node combiner. */ | |
119 | 3 | private static final NodeCombiner DEFAULT_COMBINER = new UnionCombiner(); |
120 | ||
121 | /** Stores the combiner. */ | |
122 | private NodeCombiner nodeCombiner; | |
123 | ||
124 | /** Stores the combined root node. */ | |
125 | private ConfigurationNode combinedRoot; | |
126 | ||
127 | /** Stores a list with the contained configurations. */ | |
128 | private List configurations; | |
129 | ||
130 | /** Stores a map with the named configurations. */ | |
131 | private Map namedConfigurations; | |
132 | ||
133 | /** | |
134 | * Creates a new instance of <code>CombinedConfiguration</code> and | |
135 | * initializes the combiner to be used. | |
136 | * | |
137 | * @param comb the node combiner (can be <b>null</b>, then a union combiner | |
138 | * is used as default) | |
139 | */ | |
140 | public CombinedConfiguration(NodeCombiner comb) | |
141 | 45 | { |
142 | 45 | setNodeCombiner((comb != null) ? comb : DEFAULT_COMBINER); |
143 | 45 | clear(); |
144 | 45 | } |
145 | ||
146 | /** | |
147 | * Creates a new instance of <code>CombinedConfiguration</code> that uses | |
148 | * a union combiner. | |
149 | * | |
150 | * @see org.apache.commons.configuration.tree.UnionCombiner | |
151 | */ | |
152 | public CombinedConfiguration() | |
153 | { | |
154 | 39 | this(null); |
155 | 39 | } |
156 | ||
157 | /** | |
158 | * Returns the node combiner that is used for creating the combined node | |
159 | * structure. | |
160 | * | |
161 | * @return the node combiner | |
162 | */ | |
163 | public NodeCombiner getNodeCombiner() | |
164 | { | |
165 | 361 | return nodeCombiner; |
166 | } | |
167 | ||
168 | /** | |
169 | * Sets the node combiner. This object will be used when the combined node | |
170 | * structure is to be constructed. It must not be <b>null</b>, otherwise an | |
171 | * <code>IllegalArgumentException</code> exception is thrown. Changing the | |
172 | * node combiner causes an invalidation of this combined configuration, so | |
173 | * that the new combiner immediately takes effect. | |
174 | * | |
175 | * @param nodeCombiner the node combiner | |
176 | */ | |
177 | public void setNodeCombiner(NodeCombiner nodeCombiner) | |
178 | { | |
179 | 64 | if (nodeCombiner == null) |
180 | { | |
181 | 1 | throw new IllegalArgumentException( |
182 | "Node combiner must not be null!"); | |
183 | } | |
184 | 63 | this.nodeCombiner = nodeCombiner; |
185 | 63 | invalidate(); |
186 | 63 | } |
187 | ||
188 | /** | |
189 | * Adds a new configuration to this combined configuration. It is possible | |
190 | * (but not mandatory) to give the new configuration a name. This name must | |
191 | * be unique, otherwise a <code>ConfigurationRuntimeException</code> will | |
192 | * be thrown. With the optional <code>at</code> argument you can specify | |
193 | * where in the resulting node structure the content of the added | |
194 | * configuration should appear. This is a string that uses dots as property | |
195 | * delimiters (independent on the current expression engine). For instance | |
196 | * if you pass in the string <code>"database.tables"</code>, | |
197 | * all properties of the added configuration will occur in this branch. | |
198 | * | |
199 | * @param config the configuration to add (must not be <b>null</b>) | |
200 | * @param name the name of this configuration (can be <b>null</b>) | |
201 | * @param at the position of this configuration in the combined tree (can be | |
202 | * <b>null</b>) | |
203 | */ | |
204 | public void addConfiguration(AbstractConfiguration config, String name, | |
205 | String at) | |
206 | { | |
207 | 80 | if (config == null) |
208 | { | |
209 | 1 | throw new IllegalArgumentException( |
210 | "Added configuration must not be null!"); | |
211 | } | |
212 | 79 | if (name != null && namedConfigurations.containsKey(name)) |
213 | { | |
214 | 1 | throw new ConfigurationRuntimeException( |
215 | "A configuration with the name '" | |
216 | + name | |
217 | + "' already exists in this combined configuration!"); | |
218 | } | |
219 | ||
220 | 78 | ConfigData cd = new ConfigData(config, name, at); |
221 | 78 | configurations.add(cd); |
222 | 78 | if (name != null) |
223 | { | |
224 | 32 | namedConfigurations.put(name, config); |
225 | } | |
226 | ||
227 | 78 | config.addConfigurationListener(this); |
228 | 78 | invalidate(); |
229 | 78 | } |
230 | ||
231 | /** | |
232 | * Adds a new configuration to this combined configuration with an optional | |
233 | * name. The new configuration's properties will be added under the root of | |
234 | * the combined node structure. | |
235 | * | |
236 | * @param config the configuration to add (must not be <b>null</b>) | |
237 | * @param name the name of this configuration (can be <b>null</b>) | |
238 | */ | |
239 | public void addConfiguration(AbstractConfiguration config, String name) | |
240 | { | |
241 | 13 | addConfiguration(config, name, null); |
242 | 13 | } |
243 | ||
244 | /** | |
245 | * Adds a new configuration to this combined configuration. The new | |
246 | * configuration is not given a name. Its properties will be added under the | |
247 | * root of the combined node structure. | |
248 | * | |
249 | * @param config the configuration to add (must not be <b>null</b>) | |
250 | */ | |
251 | public void addConfiguration(AbstractConfiguration config) | |
252 | { | |
253 | 8 | addConfiguration(config, null, null); |
254 | 7 | } |
255 | ||
256 | /** | |
257 | * Returns the number of configurations that are contained in this combined | |
258 | * configuration. | |
259 | * | |
260 | * @return the number of contained configurations | |
261 | */ | |
262 | public int getNumberOfConfigurations() | |
263 | { | |
264 | 65 | return configurations.size(); |
265 | } | |
266 | ||
267 | /** | |
268 | * Returns the configuration at the specified index. The contained | |
269 | * configurations are numbered in the order they were added to this combined | |
270 | * configuration. The index of the first configuration is 0. | |
271 | * | |
272 | * @param index the index | |
273 | * @return the configuration at this index | |
274 | */ | |
275 | public Configuration getConfiguration(int index) | |
276 | { | |
277 | 37 | ConfigData cd = (ConfigData) configurations.get(index); |
278 | 37 | return cd.getConfiguration(); |
279 | } | |
280 | ||
281 | /** | |
282 | * Returns the configuration with the given name. This can be <b>null</b> | |
283 | * if no such configuration exists. | |
284 | * | |
285 | * @param name the name of the configuration | |
286 | * @return the configuration with this name | |
287 | */ | |
288 | public Configuration getConfiguration(String name) | |
289 | { | |
290 | 13 | return (Configuration) namedConfigurations.get(name); |
291 | } | |
292 | ||
293 | /** | |
294 | * Removes the specified configuration from this combined configuration. | |
295 | * | |
296 | * @param config the configuration to be removed | |
297 | * @return a flag whether this configuration was found and could be removed | |
298 | */ | |
299 | public boolean removeConfiguration(Configuration config) | |
300 | { | |
301 | 5 | for (int index = 0; index < getNumberOfConfigurations(); index++) |
302 | { | |
303 | 4 | if (((ConfigData) configurations.get(index)).getConfiguration() == config) |
304 | { | |
305 | 4 | removeConfigurationAt(index); |
306 | 4 | return true; |
307 | } | |
308 | } | |
309 | ||
310 | 1 | return false; |
311 | } | |
312 | ||
313 | /** | |
314 | * Removes the configuration at the specified index. | |
315 | * | |
316 | * @param index the index | |
317 | * @return the removed configuration | |
318 | */ | |
319 | public Configuration removeConfigurationAt(int index) | |
320 | { | |
321 | 6 | ConfigData cd = (ConfigData) configurations.remove(index); |
322 | 6 | if (cd.getName() != null) |
323 | { | |
324 | 4 | namedConfigurations.remove(cd.getName()); |
325 | } | |
326 | 6 | cd.getConfiguration().removeConfigurationListener(this); |
327 | 6 | invalidate(); |
328 | 6 | return cd.getConfiguration(); |
329 | } | |
330 | ||
331 | /** | |
332 | * Removes the configuration with the specified name. | |
333 | * | |
334 | * @param name the name of the configuration to be removed | |
335 | * @return the removed configuration (<b>null</b> if this configuration | |
336 | * was not found) | |
337 | */ | |
338 | public Configuration removeConfiguration(String name) | |
339 | { | |
340 | 3 | Configuration conf = getConfiguration(name); |
341 | 3 | if (conf != null) |
342 | { | |
343 | 2 | removeConfiguration(conf); |
344 | } | |
345 | 3 | return conf; |
346 | } | |
347 | ||
348 | /** | |
349 | * Returns a set with the names of all configurations contained in this | |
350 | * combined configuration. Of course here are only these configurations | |
351 | * listed, for which a name was specified when they were added. | |
352 | * | |
353 | * @return a set with the names of the contained configurations (never | |
354 | * <b>null</b>) | |
355 | */ | |
356 | public Set getConfigurationNames() | |
357 | { | |
358 | 14 | return namedConfigurations.keySet(); |
359 | } | |
360 | ||
361 | /** | |
362 | * Invalidates this combined configuration. This means that the next time a | |
363 | * property is accessed the combined node structure must be re-constructed. | |
364 | * Invalidation of a combined configuration also means that an event of type | |
365 | * <code>EVENT_COMBINED_INVALIDATE</code> is fired. Note that while other | |
366 | * events most times appear twice (once before and once after an update), | |
367 | * this event is only fired once (after update). | |
368 | */ | |
369 | public void invalidate() | |
370 | { | |
371 | 211 | synchronized (getNodeCombiner()) // use combiner as lock |
372 | { | |
373 | 211 | combinedRoot = null; |
374 | 211 | } |
375 | 211 | fireEvent(EVENT_COMBINED_INVALIDATE, null, null, false); |
376 | 211 | } |
377 | ||
378 | /** | |
379 | * Event listener call back for configuration update events. This method is | |
380 | * called whenever one of the contained configurations was modified. It | |
381 | * invalidates this combined configuration. | |
382 | * | |
383 | * @param event the update event | |
384 | */ | |
385 | public void configurationChanged(ConfigurationEvent event) | |
386 | { | |
387 | 16 | invalidate(); |
388 | 16 | } |
389 | ||
390 | /** | |
391 | * Returns the configuration root node of this combined configuration. This | |
392 | * method will construct a combined node structure using the current node | |
393 | * combiner if necessary. | |
394 | * | |
395 | * @return the combined root node | |
396 | */ | |
397 | public ConfigurationNode getRootNode() | |
398 | { | |
399 | 97 | synchronized (getNodeCombiner()) |
400 | { | |
401 | 97 | if (combinedRoot == null) |
402 | { | |
403 | 36 | combinedRoot = constructCombinedNode(); |
404 | } | |
405 | 97 | return combinedRoot; |
406 | 0 | } |
407 | } | |
408 | ||
409 | /** | |
410 | * Clears this configuration. All contained configurations will be removed. | |
411 | */ | |
412 | public void clear() | |
413 | { | |
414 | 48 | fireEvent(EVENT_CLEAR, null, null, true); |
415 | 48 | configurations = new ArrayList(); |
416 | 48 | namedConfigurations = new HashMap(); |
417 | 48 | fireEvent(EVENT_CLEAR, null, null, false); |
418 | 48 | invalidate(); |
419 | 48 | } |
420 | ||
421 | /** | |
422 | * Returns a copy of this object. This implementation performs a deep clone, | |
423 | * i.e. all contained configurations will be cloned, too. For this to work, | |
424 | * all contained configurations must be cloneable. Registered event | |
425 | * listeners won't be cloned. The clone will use the same node combiner than | |
426 | * the original. | |
427 | * | |
428 | * @return the copied object | |
429 | */ | |
430 | public Object clone() | |
431 | { | |
432 | 2 | CombinedConfiguration copy = (CombinedConfiguration) super.clone(); |
433 | 2 | copy.clear(); |
434 | 8 | for (Iterator it = configurations.iterator(); it.hasNext();) |
435 | { | |
436 | 4 | ConfigData cd = (ConfigData) it.next(); |
437 | 4 | copy.addConfiguration((AbstractConfiguration) ConfigurationUtils |
438 | .cloneConfiguration(cd.getConfiguration()), cd.getName(), | |
439 | cd.getAt()); | |
440 | } | |
441 | ||
442 | 2 | copy.setRootNode(new DefaultConfigurationNode()); |
443 | 2 | return copy; |
444 | } | |
445 | ||
446 | /** | |
447 | * Creates the root node of this combined configuration. | |
448 | * | |
449 | * @return the combined root node | |
450 | */ | |
451 | private ConfigurationNode constructCombinedNode() | |
452 | { | |
453 | 36 | if (getNumberOfConfigurations() < 1) |
454 | { | |
455 | 7 | return new ViewNode(); |
456 | } | |
457 | ||
458 | else | |
459 | { | |
460 | 29 | Iterator it = configurations.iterator(); |
461 | 29 | ConfigurationNode node = ((ConfigData) it.next()) |
462 | .getTransformedRoot(); | |
463 | 99 | while (it.hasNext()) |
464 | { | |
465 | 41 | node = getNodeCombiner().combine(node, |
466 | ((ConfigData) it.next()).getTransformedRoot()); | |
467 | } | |
468 | 29 | return node; |
469 | } | |
470 | } | |
471 | ||
472 | /** | |
473 | * An internal helper class for storing information about contained | |
474 | * configurations. | |
475 | */ | |
476 | static class ConfigData | |
477 | { | |
478 | /** Stores a reference to the configuration. */ | |
479 | private AbstractConfiguration configuration; | |
480 | ||
481 | /** Stores the name under which the configuration is stored. */ | |
482 | private String name; | |
483 | ||
484 | /** Stores the at information as path of nodes. */ | |
485 | private Collection atPath; | |
486 | ||
487 | /** Stores the at string.*/ | |
488 | private String at; | |
489 | ||
490 | /** | |
491 | * Creates a new instance of <code>ConfigData</code> and initializes | |
492 | * it. | |
493 | * | |
494 | * @param config the configuration | |
495 | * @param n the name | |
496 | * @param at the at position | |
497 | */ | |
498 | public ConfigData(AbstractConfiguration config, String n, String at) | |
499 | 78 | { |
500 | 78 | configuration = config; |
501 | 78 | name = n; |
502 | 78 | atPath = parseAt(at); |
503 | 78 | this.at = at; |
504 | 78 | } |
505 | ||
506 | /** | |
507 | * Returns the stored configuration. | |
508 | * | |
509 | * @return the configuration | |
510 | */ | |
511 | public AbstractConfiguration getConfiguration() | |
512 | { | |
513 | 127 | return configuration; |
514 | } | |
515 | ||
516 | /** | |
517 | * Returns the configuration's name. | |
518 | * | |
519 | * @return the name | |
520 | */ | |
521 | public String getName() | |
522 | { | |
523 | 14 | return name; |
524 | } | |
525 | ||
526 | /** | |
527 | * Returns the at position of this configuration. | |
528 | * | |
529 | * @return the at position | |
530 | */ | |
531 | public String getAt() | |
532 | { | |
533 | 4 | return at; |
534 | } | |
535 | ||
536 | /** | |
537 | * Returns the transformed root node of the stored configuration. The | |
538 | * term "transformed" means that an eventually defined at path | |
539 | * has been applied. | |
540 | * | |
541 | * @return the transformed root node | |
542 | */ | |
543 | public ConfigurationNode getTransformedRoot() | |
544 | { | |
545 | 70 | ViewNode result = new ViewNode(); |
546 | 70 | ViewNode atParent = result; |
547 | ||
548 | 70 | if (atPath != null) |
549 | { | |
550 | // Build the complete path | |
551 | 32 | for (Iterator it = atPath.iterator(); it.hasNext();) |
552 | { | |
553 | 12 | ViewNode node = new ViewNode(); |
554 | 12 | node.setName((String) it.next()); |
555 | 12 | atParent.addChild(node); |
556 | 12 | atParent = node; |
557 | } | |
558 | } | |
559 | ||
560 | // Copy data of the root node to the new path | |
561 | 70 | HierarchicalConfiguration hc = ConfigurationUtils |
562 | .convertToHierarchical(getConfiguration()); | |
563 | 70 | atParent.appendChildren(hc.getRootNode()); |
564 | 70 | atParent.appendAttributes(hc.getRootNode()); |
565 | ||
566 | 70 | return result; |
567 | } | |
568 | ||
569 | /** | |
570 | * Splits the at path into its components. | |
571 | * | |
572 | * @param at the at string | |
573 | * @return a collection with the names of the single components | |
574 | */ | |
575 | private Collection parseAt(String at) | |
576 | { | |
577 | 78 | if (at == null) |
578 | { | |
579 | 67 | return null; |
580 | } | |
581 | ||
582 | 11 | Collection result = new ArrayList(); |
583 | 11 | DefaultConfigurationKey.KeyIterator it = new DefaultConfigurationKey( |
584 | AT_ENGINE, at).iterator(); | |
585 | 35 | while (it.hasNext()) |
586 | { | |
587 | 13 | result.add(it.nextKey()); |
588 | } | |
589 | 11 | return result; |
590 | } | |
591 | } | |
592 | } |