1 /*
2 * Copyright 1996-2006 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 /*
27 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
28 * (C) Copyright IBM Corp. 1996 - 1999 - All Rights Reserved
29 *
30 * The original version of this source code and documentation
31 * is copyrighted and owned by Taligent, Inc., a wholly-owned
32 * subsidiary of IBM. These materials are provided under terms
33 * of a License Agreement between Taligent and Sun. This technology
34 * is protected by multiple US and International patents.
35 *
36 * This notice and attribution to Taligent may not be removed.
37 * Taligent is a registered trademark of Taligent, Inc.
38 *
39 */
40
41 package java.util;
42
43 import java.io.IOException;
44 import java.io.InputStream;
45 import java.lang.ref.ReferenceQueue;
46 import java.lang.ref.SoftReference;
47 import java.lang.ref.WeakReference;
48 import java.net.JarURLConnection;
49 import java.net.URL;
50 import java.net.URLConnection;
51 import java.security.AccessController;
52 import java.security.PrivilegedAction;
53 import java.security.PrivilegedActionException;
54 import java.security.PrivilegedExceptionAction;
55 import java.util.concurrent.ConcurrentHashMap;
56 import java.util.concurrent.ConcurrentMap;
57 import java.util.jar.JarEntry;
58
59
60 /**
61 *
62 * Resource bundles contain locale-specific objects.
63 * When your program needs a locale-specific resource,
64 * a <code>String</code> for example, your program can load it
65 * from the resource bundle that is appropriate for the
66 * current user's locale. In this way, you can write
67 * program code that is largely independent of the user's
68 * locale isolating most, if not all, of the locale-specific
69 * information in resource bundles.
70 *
71 * <p>
72 * This allows you to write programs that can:
73 * <UL type=SQUARE>
74 * <LI> be easily localized, or translated, into different languages
75 * <LI> handle multiple locales at once
76 * <LI> be easily modified later to support even more locales
77 * </UL>
78 *
79 * <P>
80 * Resource bundles belong to families whose members share a common base
81 * name, but whose names also have additional components that identify
82 * their locales. For example, the base name of a family of resource
83 * bundles might be "MyResources". The family should have a default
84 * resource bundle which simply has the same name as its family -
85 * "MyResources" - and will be used as the bundle of last resort if a
86 * specific locale is not supported. The family can then provide as
87 * many locale-specific members as needed, for example a German one
88 * named "MyResources_de".
89 *
90 * <P>
91 * Each resource bundle in a family contains the same items, but the items have
92 * been translated for the locale represented by that resource bundle.
93 * For example, both "MyResources" and "MyResources_de" may have a
94 * <code>String</code> that's used on a button for canceling operations.
95 * In "MyResources" the <code>String</code> may contain "Cancel" and in
96 * "MyResources_de" it may contain "Abbrechen".
97 *
98 * <P>
99 * If there are different resources for different countries, you
100 * can make specializations: for example, "MyResources_de_CH" contains objects for
101 * the German language (de) in Switzerland (CH). If you want to only
102 * modify some of the resources
103 * in the specialization, you can do so.
104 *
105 * <P>
106 * When your program needs a locale-specific object, it loads
107 * the <code>ResourceBundle</code> class using the
108 * {@link #getBundle(java.lang.String, java.util.Locale) getBundle}
109 * method:
110 * <blockquote>
111 * <pre>
112 * ResourceBundle myResources =
113 * ResourceBundle.getBundle("MyResources", currentLocale);
114 * </pre>
115 * </blockquote>
116 *
117 * <P>
118 * Resource bundles contain key/value pairs. The keys uniquely
119 * identify a locale-specific object in the bundle. Here's an
120 * example of a <code>ListResourceBundle</code> that contains
121 * two key/value pairs:
122 * <blockquote>
123 * <pre>
124 * public class MyResources extends ListResourceBundle {
125 * protected Object[][] getContents() {
126 * return new Object[][] {
127 * // LOCALIZE THE SECOND STRING OF EACH ARRAY (e.g., "OK")
128 * {"OkKey", "OK"},
129 * {"CancelKey", "Cancel"},
130 * // END OF MATERIAL TO LOCALIZE
131 * };
132 * }
133 * }
134 * </pre>
135 * </blockquote>
136 * Keys are always <code>String</code>s.
137 * In this example, the keys are "OkKey" and "CancelKey".
138 * In the above example, the values
139 * are also <code>String</code>s--"OK" and "Cancel"--but
140 * they don't have to be. The values can be any type of object.
141 *
142 * <P>
143 * You retrieve an object from resource bundle using the appropriate
144 * getter method. Because "OkKey" and "CancelKey"
145 * are both strings, you would use <code>getString</code> to retrieve them:
146 * <blockquote>
147 * <pre>
148 * button1 = new Button(myResources.getString("OkKey"));
149 * button2 = new Button(myResources.getString("CancelKey"));
150 * </pre>
151 * </blockquote>
152 * The getter methods all require the key as an argument and return
153 * the object if found. If the object is not found, the getter method
154 * throws a <code>MissingResourceException</code>.
155 *
156 * <P>
157 * Besides <code>getString</code>, <code>ResourceBundle</code> also provides
158 * a method for getting string arrays, <code>getStringArray</code>,
159 * as well as a generic <code>getObject</code> method for any other
160 * type of object. When using <code>getObject</code>, you'll
161 * have to cast the result to the appropriate type. For example:
162 * <blockquote>
163 * <pre>
164 * int[] myIntegers = (int[]) myResources.getObject("intList");
165 * </pre>
166 * </blockquote>
167 *
168 * <P>
169 * The Java Platform provides two subclasses of <code>ResourceBundle</code>,
170 * <code>ListResourceBundle</code> and <code>PropertyResourceBundle</code>,
171 * that provide a fairly simple way to create resources.
172 * As you saw briefly in a previous example, <code>ListResourceBundle</code>
173 * manages its resource as a list of key/value pairs.
174 * <code>PropertyResourceBundle</code> uses a properties file to manage
175 * its resources.
176 *
177 * <p>
178 * If <code>ListResourceBundle</code> or <code>PropertyResourceBundle</code>
179 * do not suit your needs, you can write your own <code>ResourceBundle</code>
180 * subclass. Your subclasses must override two methods: <code>handleGetObject</code>
181 * and <code>getKeys()</code>.
182 *
183 * <h4>ResourceBundle.Control</h4>
184 *
185 * The {@link ResourceBundle.Control} class provides information necessary
186 * to perform the bundle loading process by the <code>getBundle</code>
187 * factory methods that take a <code>ResourceBundle.Control</code>
188 * instance. You can implement your own subclass in order to enable
189 * non-standard resource bundle formats, change the search strategy, or
190 * define caching parameters. Refer to the descriptions of the class and the
191 * {@link #getBundle(String, Locale, ClassLoader, Control) getBundle}
192 * factory method for details.
193 *
194 * <h4>Cache Management</h4>
195 *
196 * Resource bundle instances created by the <code>getBundle</code> factory
197 * methods are cached by default, and the factory methods return the same
198 * resource bundle instance multiple times if it has been
199 * cached. <code>getBundle</code> clients may clear the cache, manage the
200 * lifetime of cached resource bundle instances using time-to-live values,
201 * or specify not to cache resource bundle instances. Refer to the
202 * descriptions of the {@linkplain #getBundle(String, Locale, ClassLoader,
203 * Control) <code>getBundle</code> factory method}, {@link
204 * #clearCache(ClassLoader) clearCache}, {@link
205 * Control#getTimeToLive(String, Locale)
206 * ResourceBundle.Control.getTimeToLive}, and {@link
207 * Control#needsReload(String, Locale, String, ClassLoader, ResourceBundle,
208 * long) ResourceBundle.Control.needsReload} for details.
209 *
210 * <h4>Example</h4>
211 *
212 * The following is a very simple example of a <code>ResourceBundle</code>
213 * subclass, <code>MyResources</code>, that manages two resources (for a larger number of
214 * resources you would probably use a <code>Map</code>).
215 * Notice that you don't need to supply a value if
216 * a "parent-level" <code>ResourceBundle</code> handles the same
217 * key with the same value (as for the okKey below).
218 * <blockquote>
219 * <pre>
220 * // default (English language, United States)
221 * public class MyResources extends ResourceBundle {
222 * public Object handleGetObject(String key) {
223 * if (key.equals("okKey")) return "Ok";
224 * if (key.equals("cancelKey")) return "Cancel";
225 * return null;
226 * }
227 *
228 * public Enumeration<String> getKeys() {
229 * return Collections.enumeration(keySet());
230 * }
231 *
232 * // Overrides handleKeySet() so that the getKeys() implementation
233 * // can rely on the keySet() value.
234 * protected Set<String> handleKeySet() {
235 * return new HashSet<String>(Arrays.asList("okKey", "cancelKey"));
236 * }
237 * }
238 *
239 * // German language
240 * public class MyResources_de extends MyResources {
241 * public Object handleGetObject(String key) {
242 * // don't need okKey, since parent level handles it.
243 * if (key.equals("cancelKey")) return "Abbrechen";
244 * return null;
245 * }
246 *
247 * protected Set<String> handleKeySet() {
248 * return new HashSet<String>(Arrays.asList("cancelKey"));
249 * }
250 * }
251 * </pre>
252 * </blockquote>
253 * You do not have to restrict yourself to using a single family of
254 * <code>ResourceBundle</code>s. For example, you could have a set of bundles for
255 * exception messages, <code>ExceptionResources</code>
256 * (<code>ExceptionResources_fr</code>, <code>ExceptionResources_de</code>, ...),
257 * and one for widgets, <code>WidgetResource</code> (<code>WidgetResources_fr</code>,
258 * <code>WidgetResources_de</code>, ...); breaking up the resources however you like.
259 *
260 * @see ListResourceBundle
261 * @see PropertyResourceBundle
262 * @see MissingResourceException
263 * @since JDK1.1
264 */
265 public abstract class ResourceBundle {
266
267 /** initial size of the bundle cache */
268 private static final int INITIAL_CACHE_SIZE = 32;
269
270 /** constant indicating that no resource bundle exists */
271 private static final ResourceBundle NONEXISTENT_BUNDLE = new ResourceBundle() {
272 public Enumeration<String> getKeys() { return null; }
273 protected Object handleGetObject(String key) { return null; }
274 public String toString() { return "NONEXISTENT_BUNDLE"; }
275 };
276
277
278 /**
279 * The cache is a map from cache keys (with bundle base name, locale, and
280 * class loader) to either a resource bundle or NONEXISTENT_BUNDLE wrapped by a
281 * BundleReference.
282 *
283 * The cache is a ConcurrentMap, allowing the cache to be searched
284 * concurrently by multiple threads. This will also allow the cache keys
285 * to be reclaimed along with the ClassLoaders they reference.
286 *
287 * This variable would be better named "cache", but we keep the old
288 * name for compatibility with some workarounds for bug 4212439.
289 */
290 private static final ConcurrentMap<CacheKey, BundleReference> cacheList
291 = new ConcurrentHashMap<CacheKey, BundleReference>(INITIAL_CACHE_SIZE);
292
293 /**
294 * This ConcurrentMap is used to keep multiple threads from loading the
295 * same bundle concurrently. The table entries are <CacheKey, Thread>
296 * where CacheKey is the key for the bundle that is under construction
297 * and Thread is the thread that is constructing the bundle.
298 * This list is manipulated in findBundleInCache and putBundleInCache.
299 */
300 private static final ConcurrentMap<CacheKey, Thread> underConstruction
301 = new ConcurrentHashMap<CacheKey, Thread>();
302
303 /**
304 * Queue for reference objects referring to class loaders or bundles.
305 */
306 private static final ReferenceQueue referenceQueue = new ReferenceQueue();
307
308 /**
309 * The parent bundle of this bundle.
310 * The parent bundle is searched by {@link #getObject getObject}
311 * when this bundle does not contain a particular resource.
312 */
313 protected ResourceBundle parent = null;
314
315 /**
316 * The locale for this bundle.
317 */
318 private Locale locale = null;
319
320 /**
321 * The base bundle name for this bundle.
322 */
323 private String name;
324
325 /**
326 * The flag indicating this bundle has expired in the cache.
327 */
328 private volatile boolean expired;
329
330 /**
331 * The back link to the cache key. null if this bundle isn't in
332 * the cache (yet) or has expired.
333 */
334 private volatile CacheKey cacheKey;
335
336 /**
337 * A Set of the keys contained only in this ResourceBundle.
338 */
339 private volatile Set<String> keySet;
340
341 /**
342 * Sole constructor. (For invocation by subclass constructors, typically
343 * implicit.)
344 */
345 public ResourceBundle() {
346 }
347
348 /**
349 * Gets a string for the given key from this resource bundle or one of its parents.
350 * Calling this method is equivalent to calling
351 * <blockquote>
352 * <code>(String) {@link #getObject(java.lang.String) getObject}(key)</code>.
353 * </blockquote>
354 *
355 * @param key the key for the desired string
356 * @exception NullPointerException if <code>key</code> is <code>null</code>
357 * @exception MissingResourceException if no object for the given key can be found
358 * @exception ClassCastException if the object found for the given key is not a string
359 * @return the string for the given key
360 */
361 public final String getString(String key) {
362 return (String) getObject(key);
363 }
364
365 /**
366 * Gets a string array for the given key from this resource bundle or one of its parents.
367 * Calling this method is equivalent to calling
368 * <blockquote>
369 * <code>(String[]) {@link #getObject(java.lang.String) getObject}(key)</code>.
370 * </blockquote>
371 *
372 * @param key the key for the desired string array
373 * @exception NullPointerException if <code>key</code> is <code>null</code>
374 * @exception MissingResourceException if no object for the given key can be found
375 * @exception ClassCastException if the object found for the given key is not a string array
376 * @return the string array for the given key
377 */
378 public final String[] getStringArray(String key) {
379 return (String[]) getObject(key);
380 }
381
382 /**
383 * Gets an object for the given key from this resource bundle or one of its parents.
384 * This method first tries to obtain the object from this resource bundle using
385 * {@link #handleGetObject(java.lang.String) handleGetObject}.
386 * If not successful, and the parent resource bundle is not null,
387 * it calls the parent's <code>getObject</code> method.
388 * If still not successful, it throws a MissingResourceException.
389 *
390 * @param key the key for the desired object
391 * @exception NullPointerException if <code>key</code> is <code>null</code>
392 * @exception MissingResourceException if no object for the given key can be found
393 * @return the object for the given key
394 */
395 public final Object getObject(String key) {
396 Object obj = handleGetObject(key);
397 if (obj == null) {
398 if (parent != null) {
399 obj = parent.getObject(key);
400 }
401 if (obj == null)
402 throw new MissingResourceException("Can't find resource for bundle "
403 +this.getClass().getName()
404 +", key "+key,
405 this.getClass().getName(),
406 key);
407 }
408 return obj;
409 }
410
411 /**
412 * Returns the locale of this resource bundle. This method can be used after a
413 * call to getBundle() to determine whether the resource bundle returned really
414 * corresponds to the requested locale or is a fallback.
415 *
416 * @return the locale of this resource bundle
417 */
418 public Locale getLocale() {
419 return locale;
420 }
421
422 /*
423 * Automatic determination of the ClassLoader to be used to load
424 * resources on behalf of the client. N.B. The client is getLoader's
425 * caller's caller.
426 */
427 private static ClassLoader getLoader() {
428 Class[] stack = getClassContext();
429 /* Magic number 2 identifies our caller's caller */
430 Class c = stack[2];
431 ClassLoader cl = (c == null) ? null : c.getClassLoader();
432 if (cl == null) {
433 // When the caller's loader is the boot class loader, cl is null
434 // here. In that case, ClassLoader.getSystemClassLoader() may
435 // return the same class loader that the application is
436 // using. We therefore use a wrapper ClassLoader to create a
437 // separate scope for bundles loaded on behalf of the Java
438 // runtime so that these bundles cannot be returned from the
439 // cache to the application (5048280).
440 cl = RBClassLoader.INSTANCE;
441 }
442 return cl;
443 }
444
445 private static native Class[] getClassContext();
446
447 /**
448 * A wrapper of ClassLoader.getSystemClassLoader().
449 */
450 private static class RBClassLoader extends ClassLoader {
451 private static final RBClassLoader INSTANCE = AccessController.doPrivileged(
452 new PrivilegedAction<RBClassLoader>() {
453 public RBClassLoader run() {
454 return new RBClassLoader();
455 }
456 });
457 private static final ClassLoader loader = ClassLoader.getSystemClassLoader();
458
459 private RBClassLoader() {
460 }
461 public Class<?> loadClass(String name) throws ClassNotFoundException {
462 if (loader != null) {
463 return loader.loadClass(name);
464 }
465 return Class.forName(name);
466 }
467 public URL getResource(String name) {
468 if (loader != null) {
469 return loader.getResource(name);
470 }
471 return ClassLoader.getSystemResource(name);
472 }
473 public InputStream getResourceAsStream(String name) {
474 if (loader != null) {
475 return loader.getResourceAsStream(name);
476 }
477 return ClassLoader.getSystemResourceAsStream(name);
478 }
479 }
480
481 /**
482 * Sets the parent bundle of this bundle.
483 * The parent bundle is searched by {@link #getObject getObject}
484 * when this bundle does not contain a particular resource.
485 *
486 * @param parent this bundle's parent bundle.
487 */
488 protected void setParent(ResourceBundle parent) {
489 assert parent != NONEXISTENT_BUNDLE;
490 this.parent = parent;
491 }
492
493 /**
494 * Key used for cached resource bundles. The key checks the base
495 * name, the locale, and the class loader to determine if the
496 * resource is a match to the requested one. The loader may be
497 * null, but the base name and the locale must have a non-null
498 * value.
499 */
500 private static final class CacheKey implements Cloneable {
501 // These three are the actual keys for lookup in Map.
502 private String name;
503 private Locale locale;
504 private LoaderReference loaderRef;
505
506 // bundle format which is necessary for calling
507 // Control.needsReload().
508 private String format;
509
510 // These time values are in CacheKey so that NONEXISTENT_BUNDLE
511 // doesn't need to be cloned for caching.
512
513 // The time when the bundle has been loaded
514 private volatile long loadTime;
515
516 // The time when the bundle expires in the cache, or either
517 // Control.TTL_DONT_CACHE or Control.TTL_NO_EXPIRATION_CONTROL.
518 private volatile long expirationTime;
519
520 // Placeholder for an error report by a Throwable
521 private Throwable cause;
522
523 // Hash code value cache to avoid recalculating the hash code
524 // of this instance.
525 private int hashCodeCache;
526
527 CacheKey(String baseName, Locale locale, ClassLoader loader) {
528 this.name = baseName;
529 this.locale = locale;
530 if (loader == null) {
531 this.loaderRef = null;
532 } else {
533 loaderRef = new LoaderReference(loader, referenceQueue, this);
534 }
535 calculateHashCode();
536 }
537
538 String getName() {
539 return name;
540 }
541
542 CacheKey setName(String baseName) {
543 if (!this.name.equals(baseName)) {
544 this.name = baseName;
545 calculateHashCode();
546 }
547 return this;
548 }
549
550 Locale getLocale() {
551 return locale;
552 }
553
554 CacheKey setLocale(Locale locale) {
555 if (!this.locale.equals(locale)) {
556 this.locale = locale;
557 calculateHashCode();
558 }
559 return this;
560 }
561
562 ClassLoader getLoader() {
563 return (loaderRef != null) ? loaderRef.get() : null;
564 }
565
566 public boolean equals(Object other) {
567 if (this == other) {
568 return true;
569 }
570 try {
571 final CacheKey otherEntry = (CacheKey)other;
572 //quick check to see if they are not equal
573 if (hashCodeCache != otherEntry.hashCodeCache) {
574 return false;
575 }
576 //are the names the same?
577 if (!name.equals(otherEntry.name)) {
578 return false;
579 }
580 // are the locales the same?
581 if (!locale.equals(otherEntry.locale)) {
582 return false;
583 }
584 //are refs (both non-null) or (both null)?
585 if (loaderRef == null) {
586 return otherEntry.loaderRef == null;
587 }
588 ClassLoader loader = loaderRef.get();
589 return (otherEntry.loaderRef != null)
590 // with a null reference we can no longer find
591 // out which class loader was referenced; so
592 // treat it as unequal
593 && (loader != null)
594 && (loader == otherEntry.loaderRef.get());
595 } catch (NullPointerException e) {
596 } catch (ClassCastException e) {
597 }
598 return false;
599 }
600
601 public int hashCode() {
602 return hashCodeCache;
603 }
604
605 private void calculateHashCode() {
606 hashCodeCache = name.hashCode() << 3;
607 hashCodeCache ^= locale.hashCode();
608 ClassLoader loader = getLoader();
609 if (loader != null) {
610 hashCodeCache ^= loader.hashCode();
611 }
612 }
613
614 public Object clone() {
615 try {
616 CacheKey clone = (CacheKey) super.clone();
617 if (loaderRef != null) {
618 clone.loaderRef = new LoaderReference(loaderRef.get(),
619 referenceQueue, clone);
620 }
621 // Clear the reference to a Throwable
622 clone.cause = null;
623 return clone;
624 } catch (CloneNotSupportedException e) {
625 //this should never happen
626 throw new InternalError();
627 }
628 }
629
630 String getFormat() {
631 return format;
632 }
633
634 void setFormat(String format) {
635 this.format = format;
636 }
637
638 private void setCause(Throwable cause) {
639 if (this.cause == null) {
640 this.cause = cause;
641 } else {
642 // Override the cause if the previous one is
643 // ClassNotFoundException.
644 if (this.cause instanceof ClassNotFoundException) {
645 this.cause = cause;
646 }
647 }
648 }
649
650 private Throwable getCause() {
651 return cause;
652 }
653
654 public String toString() {
655 String l = locale.toString();
656 if (l.length() == 0) {
657 if (locale.getVariant().length() != 0) {
658 l = "__" + locale.getVariant();
659 } else {
660 l = "\"\"";
661 }
662 }
663 return "CacheKey[" + name + ", lc=" + l + ", ldr=" + getLoader()
664 + "(format=" + format + ")]";
665 }
666 }
667
668 /**
669 * The common interface to get a CacheKey in LoaderReference and
670 * BundleReference.
671 */
672 private static interface CacheKeyReference {
673 public CacheKey getCacheKey();
674 }
675
676 /**
677 * References to class loaders are weak references, so that they can be
678 * garbage collected when nobody else is using them. The ResourceBundle
679 * class has no reason to keep class loaders alive.
680 */
681 private static final class LoaderReference extends WeakReference<ClassLoader>
682 implements CacheKeyReference {
683 private CacheKey cacheKey;
684
685 LoaderReference(ClassLoader referent, ReferenceQueue q, CacheKey key) {
686 super(referent, q);
687 cacheKey = key;
688 }
689
690 public CacheKey getCacheKey() {
691 return cacheKey;
692 }
693 }
694
695 /**
696 * References to bundles are soft references so that they can be garbage
697 * collected when they have no hard references.
698 */
699 private static final class BundleReference extends SoftReference<ResourceBundle>
700 implements CacheKeyReference {
701 private CacheKey cacheKey;
702
703 BundleReference(ResourceBundle referent, ReferenceQueue q, CacheKey key) {
704 super(referent, q);
705 cacheKey = key;
706 }
707
708 public CacheKey getCacheKey() {
709 return cacheKey;
710 }
711 }
712
713 /**
714 * Gets a resource bundle using the specified base name, the default locale,
715 * and the caller's class loader. Calling this method is equivalent to calling
716 * <blockquote>
717 * <code>getBundle(baseName, Locale.getDefault(), this.getClass().getClassLoader())</code>,
718 * </blockquote>
719 * except that <code>getClassLoader()</code> is run with the security
720 * privileges of <code>ResourceBundle</code>.
721 * See {@link #getBundle(String, Locale, ClassLoader) getBundle}
722 * for a complete description of the search and instantiation strategy.
723 *
724 * @param baseName the base name of the resource bundle, a fully qualified class name
725 * @exception java.lang.NullPointerException
726 * if <code>baseName</code> is <code>null</code>
727 * @exception MissingResourceException
728 * if no resource bundle for the specified base name can be found
729 * @return a resource bundle for the given base name and the default locale
730 */
731 public static final ResourceBundle getBundle(String baseName)
732 {
733 return getBundleImpl(baseName, Locale.getDefault(),
734 /* must determine loader here, else we break stack invariant */
735 getLoader(),
736 Control.INSTANCE);
737 }
738
739 /**
740 * Returns a resource bundle using the specified base name, the
741 * default locale and the specified control. Calling this method
742 * is equivalent to calling
743 * <pre>
744 * getBundle(baseName, Locale.getDefault(),
745 * this.getClass().getClassLoader(), control),
746 * </pre>
747 * except that <code>getClassLoader()</code> is run with the security
748 * privileges of <code>ResourceBundle</code>. See {@link
749 * #getBundle(String, Locale, ClassLoader, Control) getBundle} for the
750 * complete description of the resource bundle loading process with a
751 * <code>ResourceBundle.Control</code>.
752 *
753 * @param baseName
754 * the base name of the resource bundle, a fully qualified class
755 * name
756 * @param control
757 * the control which gives information for the resource bundle
758 * loading process
759 * @return a resource bundle for the given base name and the default
760 * locale
761 * @exception NullPointerException
762 * if <code>baseName</code> or <code>control</code> is
763 * <code>null</code>
764 * @exception MissingResourceException
765 * if no resource bundle for the specified base name can be found
766 * @exception IllegalArgumentException
767 * if the given <code>control</code> doesn't perform properly
768 * (e.g., <code>control.getCandidateLocales</code> returns null.)
769 * Note that validation of <code>control</code> is performed as
770 * needed.
771 * @since 1.6
772 */
773 public static final ResourceBundle getBundle(String baseName,
774 Control control) {
775 return getBundleImpl(baseName, Locale.getDefault(),
776 /* must determine loader here, else we break stack invariant */
777 getLoader(),
778 control);
779 }
780
781 /**
782 * Gets a resource bundle using the specified base name and locale,
783 * and the caller's class loader. Calling this method is equivalent to calling
784 * <blockquote>
785 * <code>getBundle(baseName, locale, this.getClass().getClassLoader())</code>,
786 * </blockquote>
787 * except that <code>getClassLoader()</code> is run with the security
788 * privileges of <code>ResourceBundle</code>.
789 * See {@link #getBundle(String, Locale, ClassLoader) getBundle}
790 * for a complete description of the search and instantiation strategy.
791 *
792 * @param baseName
793 * the base name of the resource bundle, a fully qualified class name
794 * @param locale
795 * the locale for which a resource bundle is desired
796 * @exception NullPointerException
797 * if <code>baseName</code> or <code>locale</code> is <code>null</code>
798 * @exception MissingResourceException
799 * if no resource bundle for the specified base name can be found
800 * @return a resource bundle for the given base name and locale
801 */
802 public static final ResourceBundle getBundle(String baseName,
803 Locale locale)
804 {
805 return getBundleImpl(baseName, locale,
806 /* must determine loader here, else we break stack invariant */
807 getLoader(),
808 Control.INSTANCE);
809 }
810
811 /**
812 * Returns a resource bundle using the specified base name, target
813 * locale and control, and the caller's class loader. Calling this
814 * method is equivalent to calling
815 * <pre>
816 * getBundle(baseName, targetLocale, this.getClass().getClassLoader(),
817 * control),
818 * </pre>
819 * except that <code>getClassLoader()</code> is run with the security
820 * privileges of <code>ResourceBundle</code>. See {@link
821 * #getBundle(String, Locale, ClassLoader, Control) getBundle} for the
822 * complete description of the resource bundle loading process with a
823 * <code>ResourceBundle.Control</code>.
824 *
825 * @param baseName
826 * the base name of the resource bundle, a fully qualified
827 * class name
828 * @param targetLocale
829 * the locale for which a resource bundle is desired
830 * @param control
831 * the control which gives information for the resource
832 * bundle loading process
833 * @return a resource bundle for the given base name and a
834 * <code>Locale</code> in <code>locales</code>
835 * @exception NullPointerException
836 * if <code>baseName</code>, <code>locales</code> or
837 * <code>control</code> is <code>null</code>
838 * @exception MissingResourceException
839 * if no resource bundle for the specified base name in any
840 * of the <code>locales</code> can be found.
841 * @exception IllegalArgumentException
842 * if the given <code>control</code> doesn't perform properly
843 * (e.g., <code>control.getCandidateLocales</code> returns null.)
844 * Note that validation of <code>control</code> is performed as
845 * needed.
846 * @since 1.6
847 */
848 public static final ResourceBundle getBundle(String baseName, Locale targetLocale,
849 Control control) {
850 return getBundleImpl(baseName, targetLocale,
851 /* must determine loader here, else we break stack invariant */
852 getLoader(),
853 control);
854 }
855
856 /**
857 * Gets a resource bundle using the specified base name, locale, and class loader.
858 *
859 * <p><a name="default_behavior"/>
860 * Conceptually, <code>getBundle</code> uses the following strategy for locating and instantiating
861 * resource bundles:
862 * <p>
863 * <code>getBundle</code> uses the base name, the specified locale, and the default
864 * locale (obtained from {@link java.util.Locale#getDefault() Locale.getDefault})
865 * to generate a sequence of <a name="candidates"><em>candidate bundle names</em></a>.
866 * If the specified locale's language, country, and variant are all empty
867 * strings, then the base name is the only candidate bundle name.
868 * Otherwise, the following sequence is generated from the attribute
869 * values of the specified locale (language1, country1, and variant1)
870 * and of the default locale (language2, country2, and variant2):
871 * <ul>
872 * <li> baseName + "_" + language1 + "_" + country1 + "_" + variant1
873 * <li> baseName + "_" + language1 + "_" + country1
874 * <li> baseName + "_" + language1
875 * <li> baseName + "_" + language2 + "_" + country2 + "_" + variant2
876 * <li> baseName + "_" + language2 + "_" + country2
877 * <li> baseName + "_" + language2
878 * <li> baseName
879 * </ul>
880 * <p>
881 * Candidate bundle names where the final component is an empty string are omitted.
882 * For example, if country1 is an empty string, the second candidate bundle name is omitted.
883 *
884 * <p>
885 * <code>getBundle</code> then iterates over the candidate bundle names to find the first
886 * one for which it can <em>instantiate</em> an actual resource bundle. For each candidate
887 * bundle name, it attempts to create a resource bundle:
888 * <ul>
889 * <li>
890 * First, it attempts to load a class using the candidate bundle name.
891 * If such a class can be found and loaded using the specified class loader, is assignment
892 * compatible with ResourceBundle, is accessible from ResourceBundle, and can be instantiated,
893 * <code>getBundle</code> creates a new instance of this class and uses it as the <em>result
894 * resource bundle</em>.
895 * <li>
896 * Otherwise, <code>getBundle</code> attempts to locate a property resource file.
897 * It generates a path name from the candidate bundle name by replacing all "." characters
898 * with "/" and appending the string ".properties".
899 * It attempts to find a "resource" with this name using
900 * {@link java.lang.ClassLoader#getResource(java.lang.String) ClassLoader.getResource}.
901 * (Note that a "resource" in the sense of <code>getResource</code> has nothing to do with
902 * the contents of a resource bundle, it is just a container of data, such as a file.)
903 * If it finds a "resource", it attempts to create a new
904 * {@link PropertyResourceBundle} instance from its contents.
905 * If successful, this instance becomes the <em>result resource bundle</em>.
906 * </ul>
907 *
908 * <p>
909 * If no result resource bundle has been found, a <code>MissingResourceException</code>
910 * is thrown.
911 *
912 * <p><a name="parent_chain"/>
913 * Once a result resource bundle has been found, its <em>parent chain</em> is instantiated.
914 * <code>getBundle</code> iterates over the candidate bundle names that can be
915 * obtained by successively removing variant, country, and language
916 * (each time with the preceding "_") from the bundle name of the result resource bundle.
917 * As above, candidate bundle names where the final component is an empty string are omitted.
918 * With each of the candidate bundle names it attempts to instantiate a resource bundle, as
919 * described above.
920 * Whenever it succeeds, it calls the previously instantiated resource
921 * bundle's {@link #setParent(java.util.ResourceBundle) setParent} method
922 * with the new resource bundle, unless the previously instantiated resource
923 * bundle already has a non-null parent.
924 *
925 * <p>
926 * <code>getBundle</code> caches instantiated resource bundles and
927 * may return the same resource bundle instance multiple
928 * times.
929 *
930 * <p>
931 * The <code>baseName</code> argument should be a fully qualified class name. However, for
932 * compatibility with earlier versions, Sun's Java SE Runtime Environments do not verify this,
933 * and so it is possible to access <code>PropertyResourceBundle</code>s by specifying a
934 * path name (using "/") instead of a fully qualified class name (using ".").
935 *
936 * <p><a name="default_behavior_example"/>
937 * <strong>Example:</strong><br>The following class and property files are provided:
938 * <pre>
939 * MyResources.class
940 * MyResources.properties
941 * MyResources_fr.properties
942 * MyResources_fr_CH.class
943 * MyResources_fr_CH.properties
944 * MyResources_en.properties
945 * MyResources_es_ES.class
946 * </pre>
947 * The contents of all files are valid (that is, public non-abstract subclasses of <code>ResourceBundle</code> for
948 * the ".class" files, syntactically correct ".properties" files).
949 * The default locale is <code>Locale("en", "GB")</code>.
950 * <p>
951 * Calling <code>getBundle</code> with the shown locale argument values instantiates
952 * resource bundles from the following sources:
953 * <ul>
954 * <li>Locale("fr", "CH"): result MyResources_fr_CH.class, parent MyResources_fr.properties, parent MyResources.class
955 * <li>Locale("fr", "FR"): result MyResources_fr.properties, parent MyResources.class
956 * <li>Locale("de", "DE"): result MyResources_en.properties, parent MyResources.class
957 * <li>Locale("en", "US"): result MyResources_en.properties, parent MyResources.class
958 * <li>Locale("es", "ES"): result MyResources_es_ES.class, parent MyResources.class
959 * </ul>
960 * <p>The file MyResources_fr_CH.properties is never used because it is hidden by
961 * MyResources_fr_CH.class. Likewise, MyResources.properties is also hidden by
962 * MyResources.class.
963 *
964 * @param baseName the base name of the resource bundle, a fully qualified class name
965 * @param locale the locale for which a resource bundle is desired
966 * @param loader the class loader from which to load the resource bundle
967 * @return a resource bundle for the given base name and locale
968 * @exception java.lang.NullPointerException
969 * if <code>baseName</code>, <code>locale</code>, or <code>loader</code> is <code>null</code>
970 * @exception MissingResourceException
971 * if no resource bundle for the specified base name can be found
972 * @since 1.2
973 */
974 public static ResourceBundle getBundle(String baseName, Locale locale,
975 ClassLoader loader)
976 {
977 if (loader == null) {
978 throw new NullPointerException();
979 }
980 return getBundleImpl(baseName, locale, loader, Control.INSTANCE);
981 }
982
983 /**
984 * Returns a resource bundle using the specified base name, target
985 * locale, class loader and control. Unlike the {@linkplain
986 * #getBundle(String, Locale, ClassLoader) <code>getBundle</code>
987 * factory methods with no <code>control</code> argument}, the given
988 * <code>control</code> specifies how to locate and instantiate resource
989 * bundles. Conceptually, the bundle loading process with the given
990 * <code>control</code> is performed in the following steps.
991 *
992 * <p>
993 * <ol>
994 * <li>This factory method looks up the resource bundle in the cache for
995 * the specified <code>baseName</code>, <code>targetLocale</code> and
996 * <code>loader</code>. If the requested resource bundle instance is
997 * found in the cache and the time-to-live periods of the instance and
998 * all of its parent instances have not expired, the instance is returned
999 * to the caller. Otherwise, this factory method proceeds with the
1000 * loading process below.</li>
1001 *
1002 * <li>The {@link ResourceBundle.Control#getFormats(String)
1003 * control.getFormats} method is called to get resource bundle formats
1004 * to produce bundle or resource names. The strings
1005 * <code>"java.class"</code> and <code>"java.properties"</code>
1006 * designate class-based and {@linkplain PropertyResourceBundle
1007 * property}-based resource bundles, respectively. Other strings
1008 * starting with <code>"java."</code> are reserved for future extensions
1009 * and must not be used for application-defined formats. Other strings
1010 * designate application-defined formats.</li>
1011 *
1012 * <li>The {@link ResourceBundle.Control#getCandidateLocales(String,
1013 * Locale) control.getCandidateLocales} method is called with the target
1014 * locale to get a list of <em>candidate <code>Locale</code>s</em> for
1015 * which resource bundles are searched.</li>
1016 *
1017 * <li>The {@link ResourceBundle.Control#newBundle(String, Locale,
1018 * String, ClassLoader, boolean) control.newBundle} method is called to
1019 * instantiate a <code>ResourceBundle</code> for the base bundle name, a
1020 * candidate locale, and a format. (Refer to the note on the cache
1021 * lookup below.) This step is iterated over all combinations of the
1022 * candidate locales and formats until the <code>newBundle</code> method
1023 * returns a <code>ResourceBundle</code> instance or the iteration has
1024 * used up all the combinations. For example, if the candidate locales
1025 * are <code>Locale("de", "DE")</code>, <code>Locale("de")</code> and
1026 * <code>Locale("")</code> and the formats are <code>"java.class"</code>
1027 * and <code>"java.properties"</code>, then the following is the
1028 * sequence of locale-format combinations to be used to call
1029 * <code>control.newBundle</code>.
1030 *
1031 * <table style="width: 50%; text-align: left; margin-left: 40px;"
1032 * border="0" cellpadding="2" cellspacing="2">
1033 * <tbody><code>
1034 * <tr>
1035 * <td
1036 * style="vertical-align: top; text-align: left; font-weight: bold; width: 50%;">Locale<br>
1037 * </td>
1038 * <td
1039 * style="vertical-align: top; text-align: left; font-weight: bold; width: 50%;">format<br>
1040 * </td>
1041 * </tr>
1042 * <tr>
1043 * <td style="vertical-align: top; width: 50%;">Locale("de", "DE")<br>
1044 * </td>
1045 * <td style="vertical-align: top; width: 50%;">java.class<br>
1046 * </td>
1047 * </tr>
1048 * <tr>
1049 * <td style="vertical-align: top; width: 50%;">Locale("de", "DE")</td>
1050 * <td style="vertical-align: top; width: 50%;">java.properties<br>
1051 * </td>
1052 * </tr>
1053 * <tr>
1054 * <td style="vertical-align: top; width: 50%;">Locale("de")</td>
1055 * <td style="vertical-align: top; width: 50%;">java.class</td>
1056 * </tr>
1057 * <tr>
1058 * <td style="vertical-align: top; width: 50%;">Locale("de")</td>
1059 * <td style="vertical-align: top; width: 50%;">java.properties</td>
1060 * </tr>
1061 * <tr>
1062 * <td style="vertical-align: top; width: 50%;">Locale("")<br>
1063 * </td>
1064 * <td style="vertical-align: top; width: 50%;">java.class</td>
1065 * </tr>
1066 * <tr>
1067 * <td style="vertical-align: top; width: 50%;">Locale("")</td>
1068 * <td style="vertical-align: top; width: 50%;">java.properties</td>
1069 * </tr>
1070 * </code></tbody>
1071 * </table>
1072 * </li>
1073 *
1074 * <li>If the previous step has found no resource bundle, proceed to
1075 * Step 6. If a bundle has been found that is a base bundle (a bundle
1076 * for <code>Locale("")</code>), and the candidate locale list only contained
1077 * <code>Locale("")</code>, return the bundle to the caller. If a bundle
1078 * has been found that is a base bundle, but the candidate locale list
1079 * contained locales other than Locale(""), put the bundle on hold and
1080 * proceed to Step 6. If a bundle has been found that is not a base
1081 * bundle, proceed to Step 7.</li>
1082 *
1083 * <li>The {@link ResourceBundle.Control#getFallbackLocale(String,
1084 * Locale) control.getFallbackLocale} method is called to get a fallback
1085 * locale (alternative to the current target locale) to try further
1086 * finding a resource bundle. If the method returns a non-null locale,
1087 * it becomes the next target locale and the loading process starts over
1088 * from Step 3. Otherwise, if a base bundle was found and put on hold in
1089 * a previous Step 5, it is returned to the caller now. Otherwise, a
1090 * MissingResourceException is thrown.</li>
1091 *
1092 * <li>At this point, we have found a resource bundle that's not the
1093 * base bundle. If this bundle set its parent during its instantiation,
1094 * it is returned to the caller. Otherwise, its <a
1095 * href="./ResourceBundle.html#parent_chain">parent chain</a> is
1096 * instantiated based on the list of candidate locales from which it was
1097 * found. Finally, the bundle is returned to the caller.</li>
1098 *
1099 *
1100 * </ol>
1101 *
1102 * <p>During the resource bundle loading process above, this factory
1103 * method looks up the cache before calling the {@link
1104 * Control#newBundle(String, Locale, String, ClassLoader, boolean)
1105 * control.newBundle} method. If the time-to-live period of the
1106 * resource bundle found in the cache has expired, the factory method
1107 * calls the {@link ResourceBundle.Control#needsReload(String, Locale,
1108 * String, ClassLoader, ResourceBundle, long) control.needsReload}
1109 * method to determine whether the resource bundle needs to be reloaded.
1110 * If reloading is required, the factory method calls
1111 * <code>control.newBundle</code> to reload the resource bundle. If
1112 * <code>control.newBundle</code> returns <code>null</code>, the factory
1113 * method puts a dummy resource bundle in the cache as a mark of
1114 * nonexistent resource bundles in order to avoid lookup overhead for
1115 * subsequent requests. Such dummy resource bundles are under the same
1116 * expiration control as specified by <code>control</code>.
1117 *
1118 * <p>All resource bundles loaded are cached by default. Refer to
1119 * {@link Control#getTimeToLive(String,Locale)
1120 * control.getTimeToLive} for details.
1121 *
1122 *
1123 * <p>The following is an example of the bundle loading process with the
1124 * default <code>ResourceBundle.Control</code> implementation.
1125 *
1126 * <p>Conditions:
1127 * <ul>
1128 * <li>Base bundle name: <code>foo.bar.Messages</code>
1129 * <li>Requested <code>Locale</code>: {@link Locale#ITALY}</li>
1130 * <li>Default <code>Locale</code>: {@link Locale#FRENCH}</li>
1131 * <li>Available resource bundles:
1132 * <code>foo/bar/Messages_fr.properties</code> and
1133 * <code>foo/bar/Messages.properties</code></li>
1134 *
1135 * </ul>
1136 *
1137 * <p>First, <code>getBundle</code> tries loading a resource bundle in
1138 * the following sequence.
1139 *
1140 * <ul>
1141 * <li>class <code>foo.bar.Messages_it_IT</code>
1142 * <li>file <code>foo/bar/Messages_it_IT.properties</code>
1143 * <li>class <code>foo.bar.Messages_it</code></li>
1144 * <li>file <code>foo/bar/Messages_it.properties</code></li>
1145 * <li>class <code>foo.bar.Messages</code></li>
1146 * <li>file <code>foo/bar/Messages.properties</code></li>
1147 * </ul>
1148 *
1149 * <p>At this point, <code>getBundle</code> finds
1150 * <code>foo/bar/Messages.properties</code>, which is put on hold
1151 * because it's the base bundle. <code>getBundle</code> calls {@link
1152 * Control#getFallbackLocale(String, Locale)
1153 * control.getFallbackLocale("foo.bar.Messages", Locale.ITALY)} which
1154 * returns <code>Locale.FRENCH</code>. Next, <code>getBundle</code>
1155 * tries loading a bundle in the following sequence.
1156 *
1157 * <ul>
1158 * <li>class <code>foo.bar.Messages_fr</code></li>
1159 * <li>file <code>foo/bar/Messages_fr.properties</code></li>
1160 * <li>class <code>foo.bar.Messages</code></li>
1161 * <li>file <code>foo/bar/Messages.properties</code></li>
1162 * </ul>
1163 *
1164 * <p><code>getBundle</code> finds
1165 * <code>foo/bar/Messages_fr.properties</code> and creates a
1166 * <code>ResourceBundle</code> instance. Then, <code>getBundle</code>
1167 * sets up its parent chain from the list of the candiate locales. Only
1168 * <code>foo/bar/Messages.properties</code> is found in the list and
1169 * <code>getBundle</code> creates a <code>ResourceBundle</code> instance
1170 * that becomes the parent of the instance for
1171 * <code>foo/bar/Messages_fr.properties</code>.
1172 *
1173 * @param baseName
1174 * the base name of the resource bundle, a fully qualified
1175 * class name
1176 * @param targetLocale
1177 * the locale for which a resource bundle is desired
1178 * @param loader
1179 * the class loader from which to load the resource bundle
1180 * @param control
1181 * the control which gives information for the resource
1182 * bundle loading process
1183 * @return a resource bundle for the given base name and locale
1184 * @exception NullPointerException
1185 * if <code>baseName</code>, <code>targetLocale</code>,
1186 * <code>loader</code>, or <code>control</code> is
1187 * <code>null</code>
1188 * @exception MissingResourceException
1189 * if no resource bundle for the specified base name can be found
1190 * @exception IllegalArgumentException
1191 * if the given <code>control</code> doesn't perform properly
1192 * (e.g., <code>control.getCandidateLocales</code> returns null.)
1193 * Note that validation of <code>control</code> is performed as
1194 * needed.
1195 * @since 1.6
1196 */
1197 public static ResourceBundle getBundle(String baseName, Locale targetLocale,
1198 ClassLoader loader, Control control) {
1199 if (loader == null || control == null) {
1200 throw new NullPointerException();
1201 }
1202 return getBundleImpl(baseName, targetLocale, loader, control);
1203 }
1204
1205 private static ResourceBundle getBundleImpl(String baseName, Locale locale,
1206 ClassLoader loader, Control control) {
1207 if (locale == null || control == null) {
1208 throw new NullPointerException();
1209 }
1210
1211 // We create a CacheKey here for use by this call. The base
1212 // name and loader will never change during the bundle loading
1213 // process. We have to make sure that the locale is set before
1214 // using it as a cache key.
1215 CacheKey cacheKey = new CacheKey(baseName, locale, loader);
1216 ResourceBundle bundle = null;
1217
1218 // Quick lookup of the cache.
1219 BundleReference bundleRef = cacheList.get(cacheKey);
1220 if (bundleRef != null) {
1221 bundle = bundleRef.get();
1222 bundleRef = null;
1223 }
1224
1225 // If this bundle and all of its parents are valid (not expired),
1226 // then return this bundle. If any of the bundles is expired, we
1227 // don't call control.needsReload here but instead drop into the
1228 // complete loading process below.
1229 if (isValidBundle(bundle) && hasValidParentChain(bundle)) {
1230 return bundle;
1231 }
1232
1233 // No valid bundle was found in the cache, so we need to load the
1234 // resource bundle and its parents.
1235
1236 boolean isKnownControl = (control == Control.INSTANCE) ||
1237 (control instanceof SingleFormatControl);
1238 List<String> formats = control.getFormats(baseName);
1239 if (!isKnownControl && !checkList(formats)) {
1240 throw new IllegalArgumentException("Invalid Control: getFormats");
1241 }
1242
1243 ResourceBundle baseBundle = null;
1244 for (Locale targetLocale = locale;
1245 targetLocale != null;
1246 targetLocale = control.getFallbackLocale(baseName, targetLocale)) {
1247 List<Locale> candidateLocales = control.getCandidateLocales(baseName, targetLocale);
1248 if (!isKnownControl && !checkList(candidateLocales)) {
1249 throw new IllegalArgumentException("Invalid Control: getCandidateLocales");
1250 }
1251
1252 bundle = findBundle(cacheKey, candidateLocales, formats, 0, control, baseBundle);
1253
1254 // If the loaded bundle is the base bundle and exactly for the
1255 // requested locale or the only candidate locale, then take the
1256 // bundle as the resulting one. If the loaded bundle is the base
1257 // bundle, it's put on hold until we finish processing all
1258 // fallback locales.
1259 if (isValidBundle(bundle)) {
1260 boolean isBaseBundle = Locale.ROOT.equals(bundle.locale);
1261 if (!isBaseBundle || bundle.locale.equals(locale)
1262 || (candidateLocales.size() == 1
1263 && bundle.locale.equals(candidateLocales.get(0)))) {
1264 break;
1265 }
1266
1267 // If the base bundle has been loaded, keep the reference in
1268 // baseBundle so that we can avoid any redundant loading in case
1269 // the control specify not to cache bundles.
1270 if (isBaseBundle && baseBundle == null) {
1271 baseBundle = bundle;
1272 }
1273 }
1274 }
1275
1276 if (bundle == null) {
1277 if (baseBundle == null) {
1278 throwMissingResourceException(baseName, locale, cacheKey.getCause());
1279 }
1280 bundle = baseBundle;
1281 }
1282
1283 return bundle;
1284 }
1285
1286 /**
1287 * Checks if the given <code>List</code> is not null, not empty,
1288 * not having null in its elements.
1289 */
1290 private static final boolean checkList(List a) {
1291 boolean valid = (a != null && a.size() != 0);
1292 if (valid) {
1293 int size = a.size();
1294 for (int i = 0; valid && i < size; i++) {
1295 valid = (a.get(i) != null);
1296 }
1297 }
1298 return valid;
1299 }
1300
1301 private static final ResourceBundle findBundle(CacheKey cacheKey,
1302 List<Locale> candidateLocales,
1303 List<String> formats,
1304 int index,
1305 Control control,
1306 ResourceBundle baseBundle) {
1307 Locale targetLocale = candidateLocales.get(index);
1308 ResourceBundle parent = null;
1309 if (index != candidateLocales.size() - 1) {
1310 parent = findBundle(cacheKey, candidateLocales, formats, index + 1,
1311 control, baseBundle);
1312 } else if (baseBundle != null && Locale.ROOT.equals(targetLocale)) {
1313 return baseBundle;
1314 }
1315
1316 // Before we do the real loading work, see whether we need to
1317 // do some housekeeping: If references to class loaders or
1318 // resource bundles have been nulled out, remove all related
1319 // information from the cache.
1320 Object ref;
1321 while ((ref = referenceQueue.poll()) != null) {
1322 cacheList.remove(((CacheKeyReference)ref).getCacheKey());
1323 }
1324
1325 // flag indicating the resource bundle has expired in the cache
1326 boolean expiredBundle = false;
1327
1328 // First, look up the cache to see if it's in the cache, without
1329 // declaring beginLoading.
1330 cacheKey.setLocale(targetLocale);
1331 ResourceBundle bundle = findBundleInCache(cacheKey, control);
1332 if (isValidBundle(bundle)) {
1333 expiredBundle = bundle.expired;
1334 if (!expiredBundle) {
1335 // If its parent is the one asked for by the candidate
1336 // locales (the runtime lookup path), we can take the cached
1337 // one. (If it's not identical, then we'd have to check the
1338 // parent's parents to be consistent with what's been
1339 // requested.)
1340 if (bundle.parent == parent) {
1341 return bundle;
1342 }
1343 // Otherwise, remove the cached one since we can't keep
1344 // the same bundles having different parents.
1345 BundleReference bundleRef = cacheList.get(cacheKey);
1346 if (bundleRef != null && bundleRef.get() == bundle) {
1347 cacheList.remove(cacheKey, bundleRef);
1348 }
1349 }
1350 }
1351
1352 if (bundle != NONEXISTENT_BUNDLE) {
1353 CacheKey constKey = (CacheKey) cacheKey.clone();
1354
1355 try {
1356 // Try declaring loading. If beginLoading() returns true,
1357 // then we can proceed. Otherwise, we need to take a look
1358 // at the cache again to see if someone else has loaded
1359 // the bundle and put it in the cache while we've been
1360 // waiting for other loading work to complete.
1361 while (!beginLoading(constKey)) {
1362 bundle = findBundleInCache(cacheKey, control);
1363 if (bundle == null) {
1364 continue;
1365 }
1366 if (bundle == NONEXISTENT_BUNDLE) {
1367 // If the bundle is NONEXISTENT_BUNDLE, the bundle doesn't exist.
1368 return parent;
1369 }
1370 expiredBundle = bundle.expired;
1371 if (!expiredBundle) {
1372 if (bundle.parent == parent) {
1373 return bundle;
1374 }
1375 BundleReference bundleRef = cacheList.get(cacheKey);
1376 if (bundleRef != null && bundleRef.get() == bundle) {
1377 cacheList.remove(cacheKey, bundleRef);
1378 }
1379 }
1380 }
1381
1382 try {
1383 bundle = loadBundle(cacheKey, formats, control, expiredBundle);
1384 if (bundle != null) {
1385 if (bundle.parent == null) {
1386 bundle.setParent(parent);
1387 }
1388 bundle.locale = targetLocale;
1389 bundle = putBundleInCache(cacheKey, bundle, control);
1390 return bundle;
1391 }
1392
1393 // Put NONEXISTENT_BUNDLE in the cache as a mark that there's no bundle
1394 // instance for the locale.
1395 putBundleInCache(cacheKey, NONEXISTENT_BUNDLE, control);
1396 } finally {
1397 endLoading(constKey);
1398 }
1399 } finally {
1400 if (constKey.getCause() instanceof InterruptedException) {
1401 Thread.currentThread().interrupt();
1402 }
1403 }
1404 }
1405 assert underConstruction.get(cacheKey) != Thread.currentThread();
1406 return parent;
1407 }
1408
1409 private static final ResourceBundle loadBundle(CacheKey cacheKey,
1410 List<String> formats,
1411 Control control,
1412 boolean reload) {
1413 assert underConstruction.get(cacheKey) == Thread.currentThread();
1414
1415 // Here we actually load the bundle in the order of formats
1416 // specified by the getFormats() value.
1417 Locale targetLocale = cacheKey.getLocale();
1418
1419 ResourceBundle bundle = null;
1420 int size = formats.size();
1421 for (int i = 0; i < size; i++) {
1422 String format = formats.get(i);
1423 try {
1424 bundle = control.newBundle(cacheKey.getName(), targetLocale, format,
1425 cacheKey.getLoader(), reload);
1426 } catch (LinkageError error) {
1427 // We need to handle the LinkageError case due to
1428 // inconsistent case-sensitivity in ClassLoader.
1429 // See 6572242 for details.
1430 cacheKey.setCause(error);
1431 } catch (Exception cause) {
1432 cacheKey.setCause(cause);
1433 }
1434 if (bundle != null) {
1435 // Set the format in the cache key so that it can be
1436 // used when calling needsReload later.
1437 cacheKey.setFormat(format);
1438 bundle.name = cacheKey.getName();
1439 bundle.locale = targetLocale;
1440 // Bundle provider might reuse instances. So we should make
1441 // sure to clear the expired flag here.
1442 bundle.expired = false;
1443 break;
1444 }
1445 }
1446 assert underConstruction.get(cacheKey) == Thread.currentThread();
1447
1448 return bundle;
1449 }
1450
1451 private static final boolean isValidBundle(ResourceBundle bundle) {
1452 return bundle != null && bundle != NONEXISTENT_BUNDLE;
1453 }
1454
1455 /**
1456 * Determines whether any of resource bundles in the parent chain,
1457 * including the leaf, have expired.
1458 */
1459 private static final boolean hasValidParentChain(ResourceBundle bundle) {
1460 long now = System.currentTimeMillis();
1461 while (bundle != null) {
1462 if (bundle.expired) {
1463 return false;
1464 }
1465 CacheKey key = bundle.cacheKey;
1466 if (key != null) {
1467 long expirationTime = key.expirationTime;
1468 if (expirationTime >= 0 && expirationTime <= now) {
1469 return false;
1470 }
1471 }
1472 bundle = bundle.parent;
1473 }
1474 return true;
1475 }
1476
1477 /**
1478 * Declares the beginning of actual resource bundle loading. This method
1479 * returns true if the declaration is successful and the current thread has
1480 * been put in underConstruction. If someone else has already begun
1481 * loading, this method waits until that loading work is complete and
1482 * returns false.
1483 */
1484 private static final boolean beginLoading(CacheKey constKey) {
1485 Thread me = Thread.currentThread();
1486 Thread worker;
1487 // We need to declare by putting the current Thread (me) to
1488 // underConstruction that we are working on loading the specified
1489 // resource bundle. If we are already working the loading, it means
1490 // that the resource loading requires a recursive call. In that case,
1491 // we have to proceed. (4300693)
1492 if (((worker = underConstruction.putIfAbsent(constKey, me)) == null)
1493 || worker == me) {
1494 return true;
1495 }
1496
1497 // If someone else is working on the loading, wait until
1498 // the Thread finishes the bundle loading.
1499 synchronized (worker) {
1500 while (underConstruction.get(constKey) == worker) {
1501 try {
1502 worker.wait();
1503 } catch (InterruptedException e) {
1504 // record the interruption
1505 constKey.setCause(e);
1506 }
1507 }
1508 }
1509 return false;
1510 }
1511
1512 /**
1513 * Declares the end of the bundle loading. This method calls notifyAll
1514 * for those who are waiting for this completion.
1515 */
1516 private static final void endLoading(CacheKey constKey) {
1517 // Remove this Thread from the underConstruction map and wake up
1518 // those who have been waiting for me to complete this bundle
1519 // loading.
1520 Thread me = Thread.currentThread();
1521 assert (underConstruction.get(constKey) == me);
1522 underConstruction.remove(constKey);
1523 synchronized (me) {
1524 me.notifyAll();
1525 }
1526 }
1527
1528 /**
1529 * Throw a MissingResourceException with proper message
1530 */
1531 private static final void throwMissingResourceException(String baseName,
1532 Locale locale,
1533 Throwable cause) {
1534 // If the cause is a MissingResourceException, avoid creating
1535 // a long chain. (6355009)
1536 if (cause instanceof MissingResourceException) {
1537 cause = null;
1538 }
1539 throw new MissingResourceException("Can't find bundle for base name "
1540 + baseName + ", locale " + locale,
1541 baseName + "_" + locale, // className
1542 "", // key
1543 cause);
1544 }
1545
1546 /**
1547 * Finds a bundle in the cache. Any expired bundles are marked as
1548 * `expired' and removed from the cache upon return.
1549 *
1550 * @param cacheKey the key to look up the cache
1551 * @param control the Control to be used for the expiration control
1552 * @return the cached bundle, or null if the bundle is not found in the
1553 * cache or its parent has expired. <code>bundle.expire</code> is true
1554 * upon return if the bundle in the cache has expired.
1555 */
1556 private static final ResourceBundle findBundleInCache(CacheKey cacheKey,
1557 Control control) {
1558 BundleReference bundleRef = cacheList.get(cacheKey);
1559 if (bundleRef == null) {
1560 return null;
1561 }
1562 ResourceBundle bundle = bundleRef.get();
1563 if (bundle == null) {
1564 return null;
1565 }
1566 ResourceBundle p = bundle.parent;
1567 assert p != NONEXISTENT_BUNDLE;
1568 // If the parent has expired, then this one must also expire. We
1569 // check only the immediate parent because the actual loading is
1570 // done from the root (base) to leaf (child) and the purpose of
1571 // checking is to propagate expiration towards the leaf. For
1572 // example, if the requested locale is ja_JP_JP and there are
1573 // bundles for all of the candidates in the cache, we have a list,
1574 //
1575 // base <- ja <- ja_JP <- ja_JP_JP
1576 //
1577 // If ja has expired, then it will reload ja and the list becomes a
1578 // tree.
1579 //
1580 // base <- ja (new)
1581 // " <- ja (expired) <- ja_JP <- ja_JP_JP
1582 //
1583 // When looking up ja_JP in the cache, it finds ja_JP in the cache
1584 // which references to the expired ja. Then, ja_JP is marked as
1585 // expired and removed from the cache. This will be propagated to
1586 // ja_JP_JP.
1587 //
1588 // Now, it's possible, for example, that while loading new ja_JP,
1589 // someone else has started loading the same bundle and finds the
1590 // base bundle has expired. Then, what we get from the first
1591 // getBundle call includes the expired base bundle. However, if
1592 // someone else didn't start its loading, we wouldn't know if the
1593 // base bundle has expired at the end of the loading process. The
1594 // expiration control doesn't guarantee that the returned bundle and
1595 // its parents haven't expired.
1596 //
1597 // We could check the entire parent chain to see if there's any in
1598 // the chain that has expired. But this process may never end. An
1599 // extreme case would be that getTimeToLive returns 0 and
1600 // needsReload always returns true.
1601 if (p != null && p.expired) {
1602 assert bundle != NONEXISTENT_BUNDLE;
1603 bundle.expired = true;
1604 bundle.cacheKey = null;
1605 cacheList.remove(cacheKey, bundleRef);
1606 bundle = null;
1607 } else {
1608 CacheKey key = bundleRef.getCacheKey();
1609 long expirationTime = key.expirationTime;
1610 if (!bundle.expired && expirationTime >= 0 &&
1611 expirationTime <= System.currentTimeMillis()) {
1612 // its TTL period has expired.
1613 if (bundle != NONEXISTENT_BUNDLE) {
1614 // Synchronize here to call needsReload to avoid
1615 // redundant concurrent calls for the same bundle.
1616 synchronized (bundle) {
1617 expirationTime = key.expirationTime;
1618 if (!bundle.expired && expirationTime >= 0 &&
1619 expirationTime <= System.currentTimeMillis()) {
1620 try {
1621 bundle.expired = control.needsReload(key.getName(),
1622 key.getLocale(),
1623 key.getFormat(),
1624 key.getLoader(),
1625 bundle,
1626 key.loadTime);
1627 } catch (Exception e) {
1628 cacheKey.setCause(e);
1629 }
1630 if (bundle.expired) {
1631 // If the bundle needs to be reloaded, then
1632 // remove the bundle from the cache, but
1633 // return the bundle with the expired flag
1634 // on.
1635 bundle.cacheKey = null;
1636 cacheList.remove(cacheKey, bundleRef);
1637 } else {
1638 // Update the expiration control info. and reuse
1639 // the same bundle instance
1640 setExpirationTime(key, control);
1641 }
1642 }
1643 }
1644 } else {
1645 // We just remove NONEXISTENT_BUNDLE from the cache.
1646 cacheList.remove(cacheKey, bundleRef);
1647 bundle = null;
1648 }
1649 }
1650 }
1651 return bundle;
1652 }
1653
1654 /**
1655 * Put a new bundle in the cache.
1656 *
1657 * @param cacheKey the key for the resource bundle
1658 * @param bundle the resource bundle to be put in the cache
1659 * @return the ResourceBundle for the cacheKey; if someone has put
1660 * the bundle before this call, the one found in the cache is
1661 * returned.
1662 */
1663 private static final ResourceBundle putBundleInCache(CacheKey cacheKey,
1664 ResourceBundle bundle,
1665 Control control) {
1666 setExpirationTime(cacheKey, control);
1667 if (cacheKey.expirationTime != Control.TTL_DONT_CACHE) {
1668 CacheKey key = (CacheKey) cacheKey.clone();
1669 BundleReference bundleRef = new BundleReference(bundle, referenceQueue, key);
1670 bundle.cacheKey = key;
1671
1672 // Put the bundle in the cache if it's not been in the cache.
1673 BundleReference result = cacheList.putIfAbsent(key, bundleRef);
1674
1675 // If someone else has put the same bundle in the cache before
1676 // us and it has not expired, we should use the one in the cache.
1677 if (result != null) {
1678 ResourceBundle rb = result.get();
1679 if (rb != null && !rb.expired) {
1680 // Clear the back link to the cache key
1681 bundle.cacheKey = null;
1682 bundle = rb;
1683 // Clear the reference in the BundleReference so that
1684 // it won't be enqueued.
1685 bundleRef.clear();
1686 } else {
1687 // Replace the invalid (garbage collected or expired)
1688 // instance with the valid one.
1689 cacheList.put(key, bundleRef);
1690 }
1691 }
1692 }
1693 return bundle;
1694 }
1695
1696 private static final void setExpirationTime(CacheKey cacheKey, Control control) {
1697 long ttl = control.getTimeToLive(cacheKey.getName(),
1698 cacheKey.getLocale());
1699 if (ttl >= 0) {
1700 // If any expiration time is specified, set the time to be
1701 // expired in the cache.
1702 long now = System.currentTimeMillis();
1703 cacheKey.loadTime = now;
1704 cacheKey.expirationTime = now + ttl;
1705 } else if (ttl >= Control.TTL_NO_EXPIRATION_CONTROL) {
1706 cacheKey.expirationTime = ttl;
1707 } else {
1708 throw new IllegalArgumentException("Invalid Control: TTL=" + ttl);
1709 }
1710 }
1711
1712 /**
1713 * Removes all resource bundles from the cache that have been loaded
1714 * using the caller's class loader.
1715 *
1716 * @since 1.6
1717 * @see ResourceBundle.Control#getTimeToLive(String,Locale)
1718 */
1719 public static final void clearCache() {
1720 clearCache(getLoader());
1721 }
1722
1723 /**
1724 * Removes all resource bundles from the cache that have been loaded
1725 * using the given class loader.
1726 *
1727 * @param loader the class loader
1728 * @exception NullPointerException if <code>loader</code> is null
1729 * @since 1.6
1730 * @see ResourceBundle.Control#getTimeToLive(String,Locale)
1731 */
1732 public static final void clearCache(ClassLoader loader) {
1733 if (loader == null) {
1734 throw new NullPointerException();
1735 }
1736 Set<CacheKey> set = cacheList.keySet();
1737 for (CacheKey key : set) {
1738 if (key.getLoader() == loader) {
1739 set.remove(key);
1740 }
1741 }
1742 }
1743
1744 /**
1745 * Gets an object for the given key from this resource bundle.
1746 * Returns null if this resource bundle does not contain an
1747 * object for the given key.
1748 *
1749 * @param key the key for the desired object
1750 * @exception NullPointerException if <code>key</code> is <code>null</code>
1751 * @return the object for the given key, or null
1752 */
1753 protected abstract Object handleGetObject(String key);
1754
1755 /**
1756 * Returns an enumeration of the keys.
1757 *
1758 * @return an <code>Enumeration</code> of the keys contained in
1759 * this <code>ResourceBundle</code> and its parent bundles.
1760 */
1761 public abstract Enumeration<String> getKeys();
1762
1763 /**
1764 * Determines whether the given <code>key</code> is contained in
1765 * this <code>ResourceBundle</code> or its parent bundles.
1766 *
1767 * @param key
1768 * the resource <code>key</code>
1769 * @return <code>true</code> if the given <code>key</code> is
1770 * contained in this <code>ResourceBundle</code> or its
1771 * parent bundles; <code>false</code> otherwise.
1772 * @exception NullPointerException
1773 * if <code>key</code> is <code>null</code>
1774 * @since 1.6
1775 */
1776 public boolean containsKey(String key) {
1777 if (key == null) {
1778 throw new NullPointerException();
1779 }
1780 for (ResourceBundle rb = this; rb != null; rb = rb.parent) {
1781 if (rb.handleKeySet().contains(key)) {
1782 return true;
1783 }
1784 }
1785 return false;
1786 }
1787
1788 /**
1789 * Returns a <code>Set</code> of all keys contained in this
1790 * <code>ResourceBundle</code> and its parent bundles.
1791 *
1792 * @return a <code>Set</code> of all keys contained in this
1793 * <code>ResourceBundle</code> and its parent bundles.
1794 * @since 1.6
1795 */
1796 public Set<String> keySet() {
1797 Set<String> keys = new HashSet<String>();
1798 for (ResourceBundle rb = this; rb != null; rb = rb.parent) {
1799 keys.addAll(rb.handleKeySet());
1800 }
1801 return keys;
1802 }
1803
1804 /**
1805 * Returns a <code>Set</code> of the keys contained <em>only</em>
1806 * in this <code>ResourceBundle</code>.
1807 *
1808 * <p>The default implementation returns a <code>Set</code> of the
1809 * keys returned by the {@link #getKeys() getKeys} method except
1810 * for the ones for which the {@link #handleGetObject(String)
1811 * handleGetObject} method returns <code>null</code>. Once the
1812 * <code>Set</code> has been created, the value is kept in this
1813 * <code>ResourceBundle</code> in order to avoid producing the
1814 * same <code>Set</code> in the next calls. Override this method
1815 * in subclass implementations for faster handling.
1816 *
1817 * @return a <code>Set</code> of the keys contained only in this
1818 * <code>ResourceBundle</code>
1819 * @since 1.6
1820 */
1821 protected Set<String> handleKeySet() {
1822 if (keySet == null) {
1823 synchronized (this) {
1824 if (keySet == null) {
1825 Set<String> keys = new HashSet<String>();
1826 Enumeration<String> enumKeys = getKeys();
1827 while (enumKeys.hasMoreElements()) {
1828 String key = enumKeys.nextElement();
1829 if (handleGetObject(key) != null) {
1830 keys.add(key);
1831 }
1832 }
1833 keySet = keys;
1834 }
1835 }
1836 }
1837 return keySet;
1838 }
1839
1840
1841
1842 /**
1843 * <code>ResourceBundle.Control</code> defines a set of callback methods
1844 * that are invoked by the {@link ResourceBundle#getBundle(String,
1845 * Locale, ClassLoader, Control) ResourceBundle.getBundle} factory
1846 * methods during the bundle loading process. In other words, a
1847 * <code>ResourceBundle.Control</code> collaborates with the factory
1848 * methods for loading resource bundles. The default implementation of
1849 * the callback methods provides the information necessary for the
1850 * factory methods to perform the <a
1851 * href="./ResourceBundle.html#default_behavior">default behavior</a>.
1852 *
1853 * <p>In addition to the callback methods, the {@link
1854 * #toBundleName(String, Locale) toBundleName} and {@link
1855 * #toResourceName(String, String) toResourceName} methods are defined
1856 * primarily for convenience in implementing the callback
1857 * methods. However, the <code>toBundleName</code> method could be
1858 * overridden to provide different conventions in the organization and
1859 * packaging of localized resources. The <code>toResourceName</code>
1860 * method is <code>final</code> to avoid use of wrong resource and class
1861 * name separators.
1862 *
1863 * <p>Two factory methods, {@link #getControl(List)} and {@link
1864 * #getNoFallbackControl(List)}, provide
1865 * <code>ResourceBundle.Control</code> instances that implement common
1866 * variations of the default bundle loading process.
1867 *
1868 * <p>The formats returned by the {@link Control#getFormats(String)
1869 * getFormats} method and candidate locales returned by the {@link
1870 * ResourceBundle.Control#getCandidateLocales(String, Locale)
1871 * getCandidateLocales} method must be consistent in all
1872 * <code>ResourceBundle.getBundle</code> invocations for the same base
1873 * bundle. Otherwise, the <code>ResourceBundle.getBundle</code> methods
1874 * may return unintended bundles. For example, if only
1875 * <code>"java.class"</code> is returned by the <code>getFormats</code>
1876 * method for the first call to <code>ResourceBundle.getBundle</code>
1877 * and only <code>"java.properties"</code> for the second call, then the
1878 * second call will return the class-based one that has been cached
1879 * during the first call.
1880 *
1881 * <p>A <code>ResourceBundle.Control</code> instance must be thread-safe
1882 * if it's simultaneously used by multiple threads.
1883 * <code>ResourceBundle.getBundle</code> does not synchronize to call
1884 * the <code>ResourceBundle.Control</code> methods. The default
1885 * implementations of the methods are thread-safe.
1886 *
1887 * <p>Applications can specify <code>ResourceBundle.Control</code>
1888 * instances returned by the <code>getControl</code> factory methods or
1889 * created from a subclass of <code>ResourceBundle.Control</code> to
1890 * customize the bundle loading process. The following are examples of
1891 * changing the default bundle loading process.
1892 *
1893 * <p><b>Example 1</b>
1894 *
1895 * <p>The following code lets <code>ResourceBundle.getBundle</code> look
1896 * up only properties-based resources.
1897 *
1898 * <pre>
1899 * import java.util.*;
1900 * import static java.util.ResourceBundle.Control.*;
1901 * ...
1902 * ResourceBundle bundle =
1903 * ResourceBundle.getBundle("MyResources", new Locale("fr", "CH"),
1904 * ResourceBundle.Control.getControl(FORMAT_PROPERTIES));
1905 * </pre>
1906 *
1907 * Given the resource bundles in the <a
1908 * href="./ResourceBundle.html#default_behavior_example">example</a> in
1909 * the <code>ResourceBundle.getBundle</code> description, this
1910 * <code>ResourceBundle.getBundle</code> call loads
1911 * <code>MyResources_fr_CH.properties</code> whose parent is
1912 * <code>MyResources_fr.properties</code> whose parent is
1913 * <code>MyResources.properties</code>. (<code>MyResources_fr_CH.properties</code>
1914 * is not hidden, but <code>MyResources_fr_CH.class</code> is.)
1915 *
1916 * <p><b>Example 2</b>
1917 *
1918 * <p>The following is an example of loading XML-based bundles
1919 * using {@link Properties#loadFromXML(java.io.InputStream)
1920 * Properties.loadFromXML}.
1921 *
1922 * <pre>
1923 * ResourceBundle rb = ResourceBundle.getBundle("Messages",
1924 * new ResourceBundle.Control() {
1925 * public List<String> getFormats(String baseName) {
1926 * if (baseName == null)
1927 * throw new NullPointerException();
1928 * return Arrays.asList("xml");
1929 * }
1930 * public ResourceBundle newBundle(String baseName,
1931 * Locale locale,
1932 * String format,
1933 * ClassLoader loader,
1934 * boolean reload)
1935 * throws IllegalAccessException,
1936 * InstantiationException,
1937 * IOException {
1938 * if (baseName == null || locale == null
1939 * || format == null || loader == null)
1940 * throw new NullPointerException();
1941 * ResourceBundle bundle = null;
1942 * if (format.equals("xml")) {
1943 * String bundleName = toBundleName(baseName, locale);
1944 * String resourceName = toResourceName(bundleName, format);
1945 * InputStream stream = null;
1946 * if (reload) {
1947 * URL url = loader.getResource(resourceName);
1948 * if (url != null) {
1949 * URLConnection connection = url.openConnection();
1950 * if (connection != null) {
1951 * // Disable caches to get fresh data for
1952 * // reloading.
1953 * connection.setUseCaches(false);
1954 * stream = connection.getInputStream();
1955 * }
1956 * }
1957 * } else {
1958 * stream = loader.getResourceAsStream(resourceName);
1959 * }
1960 * if (stream != null) {
1961 * BufferedInputStream bis = new BufferedInputStream(stream);
1962 * bundle = new XMLResourceBundle(bis);
1963 * bis.close();
1964 * }
1965 * }
1966 * return bundle;
1967 * }
1968 * });
1969 *
1970 * ...
1971 *
1972 * private static class XMLResourceBundle extends ResourceBundle {
1973 * private Properties props;
1974 * XMLResourceBundle(InputStream stream) throws IOException {
1975 * props = new Properties();
1976 * props.loadFromXML(stream);
1977 * }
1978 * protected Object handleGetObject(String key) {
1979 * return props.getProperty(key);
1980 * }
1981 * public Enumeration<String> getKeys() {
1982 * ...
1983 * }
1984 * }
1985 * </pre>
1986 *
1987 * @since 1.6
1988 */
1989 public static class Control {
1990 /**
1991 * The default format <code>List</code>, which contains the strings
1992 * <code>"java.class"</code> and <code>"java.properties"</code>, in
1993 * this order. This <code>List</code> is {@linkplain
1994 * Collections#unmodifiableList(List) unmodifiable}.
1995 *
1996 * @see #getFormats(String)
1997 */
1998 public static final List<String> FORMAT_DEFAULT
1999 = Collections.unmodifiableList(Arrays.asList("java.class",
2000 "java.properties"));
2001
2002 /**
2003 * The class-only format <code>List</code> containing
2004 * <code>"java.class"</code>. This <code>List</code> is {@linkplain
2005 * Collections#unmodifiableList(List) unmodifiable}.
2006 *
2007 * @see #getFormats(String)
2008 */
2009 public static final List<String> FORMAT_CLASS
2010 = Collections.unmodifiableList(Arrays.asList("java.class"));
2011
2012 /**
2013 * The properties-only format <code>List</code> containing
2014 * <code>"java.properties"</code>. This <code>List</code> is
2015 * {@linkplain Collections#unmodifiableList(List) unmodifiable}.
2016 *
2017 * @see #getFormats(String)
2018 */
2019 public static final List<String> FORMAT_PROPERTIES
2020 = Collections.unmodifiableList(Arrays.asList("java.properties"));
2021
2022 /**
2023 * The time-to-live constant for not caching loaded resource bundle
2024 * instances.
2025 *
2026 * @see #getTimeToLive(String, Locale)
2027 */
2028 public static final long TTL_DONT_CACHE = -1;
2029
2030 /**
2031 * The time-to-live constant for disabling the expiration control
2032 * for loaded resource bundle instances in the cache.
2033 *
2034 * @see #getTimeToLive(String, Locale)
2035 */
2036 public static final long TTL_NO_EXPIRATION_CONTROL = -2;
2037
2038 private static final Control INSTANCE = new Control();
2039
2040 /**
2041 * Sole constructor. (For invocation by subclass constructors,
2042 * typically implicit.)
2043 */
2044 protected Control() {
2045 }
2046
2047 /**
2048 * Returns a <code>ResourceBundle.Control</code> in which the {@link
2049 * #getFormats(String) getFormats} method returns the specified
2050 * <code>formats</code>. The <code>formats</code> must be equal to
2051 * one of {@link Control#FORMAT_PROPERTIES}, {@link
2052 * Control#FORMAT_CLASS} or {@link
2053 * Control#FORMAT_DEFAULT}. <code>ResourceBundle.Control</code>
2054 * instances returned by this method are singletons and thread-safe.
2055 *
2056 * <p>Specifying {@link Control#FORMAT_DEFAULT} is equivalent to
2057 * instantiating the <code>ResourceBundle.Control</code> class,
2058 * except that this method returns a singleton.
2059 *
2060 * @param formats
2061 * the formats to be returned by the
2062 * <code>ResourceBundle.Control.getFormats</code> method
2063 * @return a <code>ResourceBundle.Control</code> supporting the
2064 * specified <code>formats</code>
2065 * @exception NullPointerException
2066 * if <code>formats</code> is <code>null</code>
2067 * @exception IllegalArgumentException
2068 * if <code>formats</code> is unknown
2069 */
2070 public static final Control getControl(List<String> formats) {
2071 if (formats.equals(Control.FORMAT_PROPERTIES)) {
2072 return SingleFormatControl.PROPERTIES_ONLY;
2073 }
2074 if (formats.equals(Control.FORMAT_CLASS)) {
2075 return SingleFormatControl.CLASS_ONLY;
2076 }
2077 if (formats.equals(Control.FORMAT_DEFAULT)) {
2078 return Control.INSTANCE;
2079 }
2080 throw new IllegalArgumentException();
2081 }
2082
2083 /**
2084 * Returns a <code>ResourceBundle.Control</code> in which the {@link
2085 * #getFormats(String) getFormats} method returns the specified
2086 * <code>formats</code> and the {@link
2087 * Control#getFallbackLocale(String, Locale) getFallbackLocale}
2088 * method returns <code>null</code>. The <code>formats</code> must
2089 * be equal to one of {@link Control#FORMAT_PROPERTIES}, {@link
2090 * Control#FORMAT_CLASS} or {@link Control#FORMAT_DEFAULT}.
2091 * <code>ResourceBundle.Control</code> instances returned by this
2092 * method are singletons and thread-safe.
2093 *
2094 * @param formats
2095 * the formats to be returned by the
2096 * <code>ResourceBundle.Control.getFormats</code> method
2097 * @return a <code>ResourceBundle.Control</code> supporting the
2098 * specified <code>formats</code> with no fallback
2099 * <code>Locale</code> support
2100 * @exception NullPointerException
2101 * if <code>formats</code> is <code>null</code>
2102 * @exception IllegalArgumentException
2103 * if <code>formats</code> is unknown
2104 */
2105 public static final Control getNoFallbackContro
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