java.util
Class ResourceBundle

java.lang.Object
  |
  +--java.util.ResourceBundle
Direct Known Subclasses:
ListResourceBundle, PropertyResourceBundle

public abstract class ResourceBundle
extends Object

Untamed:


Field Summary
private static float CACHE_LOAD_FACTOR
          capacity of cache consumed before it should grow
private static java.util.ResourceBundle.ResourceCacheKey cacheKey
          Static key used for resource lookups.
private static sun.misc.SoftCache cacheList
          This is a SoftCache, allowing bundles to be removed from the cache if they are no longer needed.
private static Integer DEFAULT_NOT_FOUND
          NOTFOUND value used if class loader is null
private static int INITIAL_CACHE_SIZE
          initial size of the bundle cache
private  Locale locale
          The locale for this bundle.
private static int MAX_BUNDLES_SEARCHED
          Maximum length of one branch of the resource search path tree.
protected  ResourceBundle parent
          The parent bundle of this bundle.
private static Hashtable underConstruction
          This Hashtable is used to keep multiple threads from loading the same bundle concurrently.
 
Constructor Summary
ResourceBundle()
          Enabled: Sole constructor.
 
Method Summary
private static Vector calculateBundleNames(String baseName, Locale locale)
          Calculate the bundles along the search path from the base bundle to the bundle specified by baseName and locale.
private static void cleanUpConstructionList()
          Remove any entries this thread may have in the construction list.
private static Object findBundle(ClassLoader loader, String bundleName, Locale defaultLocale, String baseName, Object parent, Object NOTFOUND)
          Find a bundle in the cache or load it via the loader or a property file.
private static Object findBundleInCache(ClassLoader loader, String bundleName, Locale defaultLocale)
          Find a bundle in the cache.
static ResourceBundle getBundle(String baseName)
          Enabled: Gets a resource bundle using the specified base name, the default locale, and the caller's class loader.
static ResourceBundle getBundle(String baseName, Locale locale)
          Enabled: Gets a resource bundle using the specified base name and locale, and the caller's class loader.
static ResourceBundle getBundle(String baseName, Locale locale, ClassLoader loader)
          Enabled: Gets a resource bundle using the specified base name, locale, and class loader.
private static ResourceBundle getBundleImpl(String baseName, Locale locale, ClassLoader loader)
           
private static Class[] getClassContext()
           
abstract  Enumeration getKeys()
          Enabled: Returns an enumeration of the keys.
private static ClassLoader getLoader()
           
 Locale getLocale()
          Enabled: Returns the locale of this resource bundle.
 Object getObject(String key)
          Enabled: Gets an object for the given key from this resource bundle or one of its parents.
 String getString(String key)
          Enabled: Gets a string for the given key from this resource bundle or one of its parents.
 String[] getStringArray(String key)
          Enabled: Gets a string array for the given key from this resource bundle or one of its parents.
protected abstract  Object handleGetObject(String key)
          Gets an object for the given key from this resource bundle.
private static Object loadBundle(ClassLoader loader, String bundleName, Locale defaultLocale)
          Load a bundle through either the specified ClassLoader or from a ".properties" file and return the loaded bundle.
private static Object propagate(ClassLoader loader, Vector names, Vector bundlesFound, Locale defaultLocale, Object parent)
          propagate bundles from the root down the specified branch of the search tree.
private static void putBundleInCache(ClassLoader loader, String bundleName, Locale defaultLocale, Object value)
          Put a new bundle in the cache and notify waiting threads that a new bundle has been put in the cache.
private  void setLocale(String baseName, String bundleName)
          Sets the locale for this bundle.
protected  void setParent(ResourceBundle parent)
          Sets the parent bundle of this bundle.
private static void throwMissingResourceException(String baseName, Locale locale)
          Throw a MissingResourceException with proper message
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

cacheKey

private static final java.util.ResourceBundle.ResourceCacheKey cacheKey
Static key used for resource lookups. Concurrent access to this object is controlled by synchronizing cacheList, not cacheKey. A static object is used to do cache lookups for performance reasons - the assumption being that synchronization has a lower overhead than object allocation and subsequent garbage collection.


INITIAL_CACHE_SIZE

private static final int INITIAL_CACHE_SIZE
initial size of the bundle cache


CACHE_LOAD_FACTOR

private static final float CACHE_LOAD_FACTOR
capacity of cache consumed before it should grow


MAX_BUNDLES_SEARCHED

private static final int MAX_BUNDLES_SEARCHED
Maximum length of one branch of the resource search path tree. Used in getBundle.


underConstruction

private static final Hashtable underConstruction
This Hashtable is used to keep multiple threads from loading the same bundle concurrently. The table entries are (cacheKey, thread) where cacheKey is the key for the bundle that is under construction and thread is the thread that is constructing the bundle. This list is manipulated in findBundle and putBundleInCache. Synchronization of this object is done through cacheList, not on this object.


DEFAULT_NOT_FOUND

private static final Integer DEFAULT_NOT_FOUND
NOTFOUND value used if class loader is null


cacheList

private static sun.misc.SoftCache cacheList
This is a SoftCache, allowing bundles to be removed from the cache if they are no longer needed. This will also allow the cache keys to be reclaimed along with the ClassLoaders they reference.


parent

protected ResourceBundle parent
The parent bundle of this bundle. The parent bundle is searched by getObject when this bundle does not contain a particular resource.


locale

private Locale locale
The locale for this bundle.

Constructor Detail

ResourceBundle

public ResourceBundle()
Enabled: Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

getString

public final String getString(String key)
Enabled: Gets a string for the given key from this resource bundle or one of its parents. Calling this method is equivalent to calling
(String) getObject(key).

Parameters:
key - the key for the desired string
Returns:
the string for the given key

getStringArray

public final String[] getStringArray(String key)
Enabled: Gets a string array for the given key from this resource bundle or one of its parents. Calling this method is equivalent to calling
(String[]) getObject(key).

Parameters:
key - the key for the desired string array
Returns:
the string array for the given key

getObject

public final Object getObject(String key)
Enabled: Gets an object for the given key from this resource bundle or one of its parents. This method first tries to obtain the object from this resource bundle using handleGetObject. If not successful, and the parent resource bundle is not null, it calls the parent's getObject method. If still not successful, it throws a MissingResourceException.

Parameters:
key - the key for the desired object
Returns:
the object for the given key

getLocale

public Locale getLocale()
Enabled: Returns the locale of this resource bundle. This method can be used after a call to getBundle() to determine whether the resource bundle returned really corresponds to the requested locale or is a fallback.

Returns:
the locale of this resource bundle

setLocale

private void setLocale(String baseName,
                       String bundleName)
Sets the locale for this bundle. This is the locale that this bundle actually represents and does not depend on how the bundle was found by getBundle. Ex. if the user was looking for fr_FR and getBundle found en_US, the bundle's locale would be en_US, NOT fr_FR

Parameters:
baseName - the bundle's base name
bundleName - the complete bundle name including locale extension.

getLoader

private static ClassLoader getLoader()

getClassContext

private static Class[] getClassContext()

setParent

protected void setParent(ResourceBundle parent)
Sets the parent bundle of this bundle. The parent bundle is searched by getObject when this bundle does not contain a particular resource.

Parameters:
parent - this bundle's parent bundle.

getBundle

public static final ResourceBundle getBundle(String baseName)
Enabled: Gets a resource bundle using the specified base name, the default locale, and the caller's class loader. Calling this method is equivalent to calling
getBundle(baseName, Locale.getDefault(), this.getClass().getClassLoader()),
except that getClassLoader() is run with the security privileges of ResourceBundle. See getBundle for a complete description of the search and instantiation strategy.

Parameters:
baseName - the base name of the resource bundle, a fully qualified class name
Returns:
a resource bundle for the given base name and the default locale

getBundle

public static final ResourceBundle getBundle(String baseName,
                                             Locale locale)
Enabled: Gets a resource bundle using the specified base name and locale, and the caller's class loader. Calling this method is equivalent to calling
getBundle(baseName, locale, this.getClass().getClassLoader()),
except that getClassLoader() is run with the security privileges of ResourceBundle. See getBundle for a complete description of the search and instantiation strategy.

Parameters:
baseName - the base name of the resource bundle, a fully qualified class name
locale - the locale for which a resource bundle is desired
Returns:
a resource bundle for the given base name and locale

getBundle

public static ResourceBundle getBundle(String baseName,
                                       Locale locale,
                                       ClassLoader loader)
Enabled: Gets a resource bundle using the specified base name, locale, and class loader.

Conceptually, getBundle uses the following strategy for locating and instantiating resource bundles:

getBundle uses the base name, the specified locale, and the default locale (obtained from Locale.getDefault) to generate a sequence of candidate bundle names. If the specified locale's language, country, and variant are all empty strings, then the base name is the only candidate bundle name. Otherwise, the following sequence is generated from the attribute values of the specified locale (language1, country1, and variant1) and of the default locale (language2, country2, and variant2):

Candidate bundle names where the final component is an empty string are omitted. For example, if country1 is an empty string, the second candidate bundle name is omitted.

getBundle then iterates over the candidate bundle names to find the first one for which it can instantiate an actual resource bundle. For each candidate bundle name, it attempts to create a resource bundle:

If no result resource bundle has been found, a MissingResourceException is thrown.

Once a result resource bundle has been found, its parent chain is instantiated. getBundle iterates over the candidate bundle names that can be obtained by successively removing variant, country, and language (each time with the preceding "_") from the bundle name of the result resource bundle. As above, candidate bundle names where the final component is an empty string are omitted. With each of the candidate bundle names it attempts to instantiate a resource bundle, as described above. Whenever it succeeds, it calls the previously instantiated resource bundle's setParent method with the new resource bundle, unless the previously instantiated resource bundle already has a non-null parent.

Implementations of getBundle may cache instantiated resource bundles and return the same resource bundle instance multiple times. They may also vary the sequence in which resource bundles are instantiated as long as the selection of the result resource bundle and its parent chain are compatible with the description above.

The baseName argument should be a fully qualified class name. However, for compatibility with earlier versions, Sun's Java 2 runtime environments do not verify this, and so it is possible to access PropertyResourceBundles by specifying a path name (using "/") instead of a fully qualified class name (using ".").

Example: The following class and property files are provided: MyResources.class, MyResources_fr_CH.properties, MyResources_fr_CH.class, MyResources_fr.properties, MyResources_en.properties, MyResources_es_ES.class. The contents of all files are valid (that is, public non-abstract subclasses of ResourceBundle for the ".class" files, syntactically correct ".properties" files). The default locale is Locale("en", "UK").

Calling getBundle with the shown locale argument values instantiates resource bundles from the following sources:

The file MyResources_fr_CH.properties is never used because it is hidden by MyResources_fr_CH.class.

Parameters:
baseName - the base name of the resource bundle, a fully qualified class name
locale - the locale for which a resource bundle is desired
loader - the class loader from which to load the resource bundle
Returns:
a resource bundle for the given base name and locale
Since:
1.2

getBundleImpl

private static ResourceBundle getBundleImpl(String baseName,
                                            Locale locale,
                                            ClassLoader loader)

propagate

private static Object propagate(ClassLoader loader,
                                Vector names,
                                Vector bundlesFound,
                                Locale defaultLocale,
                                Object parent)
propagate bundles from the root down the specified branch of the search tree.

Parameters:
loader - the class loader for the bundles
names - the names of the bundles along search path
bundlesFound - the bundles corresponding to the names (some may be null)
defaultLocale - the default locale at the time getBundle was called
parent - the parent of the first bundle in the path (the root bundle)
Returns:
the value of the last bundle along the path

throwMissingResourceException

private static void throwMissingResourceException(String baseName,
                                                  Locale locale)
                                           throws MissingResourceException
Throw a MissingResourceException with proper message

MissingResourceException

cleanUpConstructionList

private static void cleanUpConstructionList()
Remove any entries this thread may have in the construction list. This is done as cleanup in the case where a bundle can't be constructed.


findBundle

private static Object findBundle(ClassLoader loader,
                                 String bundleName,
                                 Locale defaultLocale,
                                 String baseName,
                                 Object parent,
                                 Object NOTFOUND)
Find a bundle in the cache or load it via the loader or a property file. If the bundle isn't found, an entry is put in the constructionCache and null is returned. If null is returned, the caller must define the bundle by calling putBundleInCache. This routine also propagates NOTFOUND values from parent to child bundles when the parent is NOTFOUND.

Parameters:
loader - the loader to use when loading a bundle
bundleName - the complete bundle name including locale extension
defaultLocale - the default locale at the time getBundle was called
parent - the parent of the resource bundle being loaded. null if the bundle is a root bundle
NOTFOUND - the value to use for NOTFOUND bundles.
Returns:
the bundle or null if the bundle could not be found in the cache or loaded.

calculateBundleNames

private static Vector calculateBundleNames(String baseName,
                                           Locale locale)
Calculate the bundles along the search path from the base bundle to the bundle specified by baseName and locale.

Parameters:
baseName - the base bundle name
locale - the locale

findBundleInCache

private static Object findBundleInCache(ClassLoader loader,
                                        String bundleName,
                                        Locale defaultLocale)
Find a bundle in the cache.

Parameters:
loader - the class loader that is responsible for loading the bundle.
bundleName - the complete name of the bundle including locale extension. ex. sun.text.resources.LocaleElements_fr_BE
defaultLocale - the default locale at the time getBundle was called
Returns:
the cached bundle. null if the bundle is not in the cache.

putBundleInCache

private static void putBundleInCache(ClassLoader loader,
                                     String bundleName,
                                     Locale defaultLocale,
                                     Object value)
Put a new bundle in the cache and notify waiting threads that a new bundle has been put in the cache.

Parameters:
defaultLocale - the default locale at the time getBundle was called

loadBundle

private static Object loadBundle(ClassLoader loader,
                                 String bundleName,
                                 Locale defaultLocale)
Load a bundle through either the specified ClassLoader or from a ".properties" file and return the loaded bundle.

Parameters:
loader - the ClassLoader to use to load the bundle. If null, the system ClassLoader is used.
bundleName - the name of the resource to load. The name should be complete including a qualified class name followed by the locale extension. ex. sun.text.resources.LocaleElements_fr_BE
defaultLocale - the default locale at the time getBundle was called
Returns:
the bundle or null if none could be found.

handleGetObject

protected abstract Object handleGetObject(String key)
Gets an object for the given key from this resource bundle. Returns null if this resource bundle does not contain an object for the given key.

Parameters:
key - the key for the desired object
Returns:
the object for the given key, or null

getKeys

public abstract Enumeration getKeys()
Enabled: Returns an enumeration of the keys.



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