Control
open class Control
kotlin.Any | |
↳ | java.util.ResourceBundle.Control |
ResourceBundle.Control
defines a set of callback methods that are invoked by the ResourceBundle.getBundle
factory methods during the bundle loading process. In other words, a ResourceBundle.Control
collaborates with the factory methods for loading resource bundles. The default implementation of the callback methods provides the information necessary for the factory methods to perform the default behavior.
In addition to the callback methods, the toBundleName
and toResourceName
methods are defined primarily for convenience in implementing the callback methods. However, the toBundleName
method could be overridden to provide different conventions in the organization and packaging of localized resources. The toResourceName
method is final
to avoid use of wrong resource and class name separators.
Two factory methods, getControl(java.util.List)
and getNoFallbackControl(java.util.List)
, provide ResourceBundle.Control
instances that implement common variations of the default bundle loading process.
The formats returned by the getFormats
method and candidate locales returned by the getCandidateLocales
method must be consistent in all ResourceBundle.getBundle
invocations for the same base bundle. Otherwise, the ResourceBundle.getBundle
methods may return unintended bundles. For example, if only "java.class"
is returned by the getFormats
method for the first call to ResourceBundle.getBundle
and only "java.properties"
for the second call, then the second call will return the class-based one that has been cached during the first call.
A ResourceBundle.Control
instance must be thread-safe if it's simultaneously used by multiple threads. ResourceBundle.getBundle
does not synchronize to call the ResourceBundle.Control
methods. The default implementations of the methods are thread-safe.
Applications can specify ResourceBundle.Control
instances returned by the getControl
factory methods or created from a subclass of ResourceBundle.Control
to customize the bundle loading process. The following are examples of changing the default bundle loading process.
Example 1
The following code lets ResourceBundle.getBundle
look up only properties-based resources.
import java.util.*; import static java.util.ResourceBundle.Control.*; ... ResourceBundle bundle = ResourceBundle.getBundle("MyResources", new Locale("fr", "CH"), ResourceBundle.Control.getControl(FORMAT_PROPERTIES));
ResourceBundle.getBundle
description, this ResourceBundle.getBundle
call loads MyResources_fr_CH.properties
whose parent is MyResources_fr.properties
whose parent is MyResources.properties
. (MyResources_fr_CH.properties
is not hidden, but MyResources_fr_CH.class
is.)
Example 2
The following is an example of loading XML-based bundles using Properties.loadFromXML
.
ResourceBundle rb = ResourceBundle.getBundle("Messages", new ResourceBundle.Control() { public List<String> getFormats(String baseName) { if (baseName == null) throw new NullPointerException(); return Arrays.asList("xml"); } public ResourceBundle newBundle(String baseName, Locale locale, String format, ClassLoader loader, boolean reload) throws IllegalAccessException, InstantiationException, IOException { if (baseName == null || locale == null || format == null || loader == null) throw new NullPointerException(); ResourceBundle bundle = null; if (format.equals("xml")) { String bundleName = toBundleName(baseName, locale); String resourceName = toResourceName(bundleName, format); InputStream stream = null; if (reload) { URL url = loader.getResource(resourceName); if (url != null) { URLConnection connection = url.openConnection(); if (connection != null) { // Disable caches to get fresh data for // reloading. connection.setUseCaches(false); stream = connection.getInputStream(); } } } else { stream = loader.getResourceAsStream(resourceName); } if (stream != null) { BufferedInputStream bis = new BufferedInputStream(stream); bundle = new XMLResourceBundle(bis); bis.close(); } } return bundle; } }); ... private static class XMLResourceBundle extends ResourceBundle { private Properties props; XMLResourceBundle(InputStream stream) throws IOException { props = new Properties(); props.loadFromXML(stream); } protected Object handleGetObject(String key) { return props.getProperty(key); } public Enumeration<String> getKeys() { ... } }
Summary
Constants | |
---|---|
static Long |
The time-to-live constant for not caching loaded resource bundle instances. |
static Long |
The time-to-live constant for disabling the expiration control for loaded resource bundle instances in the cache. |
Protected constructors | |
---|---|
Control() Sole constructor. |
Public methods | |
---|---|
open MutableList<Locale!>! |
getCandidateLocales(baseName: String!, locale: Locale!) Returns a |
static ResourceBundle.Control! |
getControl(formats: MutableList<String!>!) Returns a |
open Locale! |
getFallbackLocale(baseName: String!, locale: Locale!) Returns a |
open MutableList<String!>! |
getFormats(baseName: String!) Returns a |
static ResourceBundle.Control! |
getNoFallbackControl(formats: MutableList<String!>!) Returns a |
open Long |
getTimeToLive(baseName: String!, locale: Locale!) Returns the time-to-live (TTL) value for resource bundles that are loaded under this |
open Boolean |
needsReload(baseName: String!, locale: Locale!, format: String!, loader: ClassLoader!, bundle: ResourceBundle!, loadTime: Long) Determines if the expired |
open ResourceBundle! |
newBundle(baseName: String!, locale: Locale!, format: String!, loader: ClassLoader!, reload: Boolean) Instantiates a resource bundle for the given bundle name of the given format and locale, using the given class loader if necessary. |
open String! |
toBundleName(baseName: String!, locale: Locale!) Converts the given and to the bundle name. |
String! |
toResourceName(bundleName: String!, suffix: String!) Converts the given |
Properties | |
---|---|
static MutableList<String!>! |
The class-only format |
static MutableList<String!>! |
The default format |
static MutableList<String!>! |
The properties-only format |
Constants
TTL_DONT_CACHE
static val TTL_DONT_CACHE: Long
The time-to-live constant for not caching loaded resource bundle instances.
Value: -1L
See Also
TTL_NO_EXPIRATION_CONTROL
static val TTL_NO_EXPIRATION_CONTROL: Long
The time-to-live constant for disabling the expiration control for loaded resource bundle instances in the cache.
Value: -2L
See Also
Protected constructors
Control
protected Control()
Sole constructor. (For invocation by subclass constructors, typically implicit.)
Public methods
getCandidateLocales
open fun getCandidateLocales(
baseName: String!,
locale: Locale!
): MutableList<Locale!>!
Returns a List
of s as candidate locales for baseName
and locale
. This method is called by the ResourceBundle.getBundle
factory method each time the factory method tries finding a resource bundle for a target .
The sequence of the candidate locales also corresponds to the runtime resource lookup path (also known as the parent chain), if the corresponding resource bundles for the candidate locales exist and their parents are not defined by loaded resource bundles themselves. The last element of the list must be a root locale if it is desired to have the base bundle as the terminal of the parent chain.
If the given locale is equal to Locale.ROOT
(the root locale), a List
containing only the root Locale
must be returned. In this case, the ResourceBundle.getBundle
factory method loads only the base bundle as the resulting resource bundle.
It is not a requirement to return an immutable (unmodifiable) List
. However, the returned List
must not be mutated after it has been returned by getCandidateLocales
.
The default implementation returns a List
containing Locale
s using the rules described below. In the description below, L, S, C and V respectively represent non-empty language, script, country, and variant. For example, [L, C] represents a Locale
that has non-empty values only for language and country. The form L("xx") represents the (non-empty) language value is "xx". For all cases, Locale
s whose final component values are empty strings are omitted.
- For an input
Locale
with an empty script value, append candidateLocale
s by omitting the final component one by one as below:- [L, C, V]
- [L, C]
- [L]
-
Locale.ROOT
- For an input
Locale
with a non-empty script value, append candidateLocale
s by omitting the final component up to language, then append candidates generated from theLocale
with country and variant restored:- [L, S, C, V]
- [L, S, C]
- [L, S]
- [L, C, V]
- [L, C]
- [L]
-
Locale.ROOT
- For an input
Locale
with a variant value consisting of multiple subtags separated by underscore, generate candidateLocale
s by omitting the variant subtags one by one, then insert them after every occurrence ofLocale
s with the full variant value in the original list. For example, if the variant consists of two subtags V1 and V2:- [L, S, C, V1, V2]
- [L, S, C, V1]
- [L, S, C]
- [L, S]
- [L, C, V1, V2]
- [L, C, V1]
- [L, C]
- [L]
-
Locale.ROOT
- Special cases for Chinese. When an input
Locale
has the language "zh" (Chinese) and an empty script value, either "Hans" (Simplified) or "Hant" (Traditional) might be supplied, depending on the country. When the country is "CN" (China) or "SG" (Singapore), "Hans" is supplied. When the country is "HK" (Hong Kong SAR China), "MO" (Macau SAR China), or "TW" (Taiwan), "Hant" is supplied. For all other countries or when the country is empty, no script is supplied. For example, forLocale("zh", "CN")
, the candidate list will be:- [L("zh"), S("Hans"), C("CN")]
- [L("zh"), S("Hans")]
- [L("zh"), C("CN")]
- [L("zh")]
-
Locale.ROOT
Locale("zh", "TW")
, the candidate list will be:- [L("zh"), S("Hant"), C("TW")]
- [L("zh"), S("Hant")]
- [L("zh"), C("TW")]
- [L("zh")]
-
Locale.ROOT
- Special cases for Norwegian. Both
Locale("no", "NO", "NY")
andLocale("nn", "NO")
represent Norwegian Nynorsk. When a locale's language is "nn", the standard candidate list is generated up to [L("nn")], and then the following candidates are added:- [L("no"), C("NO"), V("NY")]
- [L("no"), C("NO")]
- [L("no")]
-
Locale.ROOT
Locale("no", "NO", "NY")
, it is first converted toLocale("nn", "NO")
and then the above procedure is followed.Also, Java treats the language "no" as a synonym of Norwegian Bokmål "nb". Except for the single case
Locale("no", "NO", "NY")
(handled above), when an inputLocale
has language "no" or "nb", candidateLocale
s with language code "no" and "nb" are interleaved, first using the requested language, then using its synonym. For example,Locale("nb", "NO", "POSIX")
generates the following candidate list:- [L("nb"), C("NO"), V("POSIX")]
- [L("no"), C("NO"), V("POSIX")]
- [L("nb"), C("NO")]
- [L("no"), C("NO")]
- [L("nb")]
- [L("no")]
-
Locale.ROOT
Locale("no", "NO", "POSIX")
would generate the same list except that locales with "no" would appear before the corresponding locales with "nb".
The default implementation uses an ArrayList
that overriding implementations may modify before returning it to the caller. However, a subclass must not modify it after it has been returned by getCandidateLocales
.
For example, if the given baseName
is "Messages" and the given locale
is Locale("ja", "", "XX")
, then a List
of Locale
s:
Locale("ja", "", "XX") Locale("ja") Locale.ROOT
Locale
s are found, then the runtime resource lookup path (parent chain) is:
<code>Messages_ja -> Messages </code>
Parameters | |
---|---|
baseName |
String!: the base name of the resource bundle, a fully qualified class name |
locale |
Locale!: the locale for which a resource bundle is desired |
Return | |
---|---|
MutableList<Locale!>! |
a List of candidate Locale s for the given locale |
Exceptions | |
---|---|
java.lang.NullPointerException |
if baseName or locale is null |
getControl
static fun getControl(formats: MutableList<String!>!): ResourceBundle.Control!
Returns a ResourceBundle.Control
in which the getFormats
method returns the specified formats
. The formats
must be equal to one of Control#FORMAT_PROPERTIES
, java.util.ResourceBundle.Control#FORMAT_CLASS
or java.util.ResourceBundle.Control#FORMAT_DEFAULT
. ResourceBundle.Control
instances returned by this method are singletons and thread-safe.
Specifying Control#FORMAT_DEFAULT
is equivalent to instantiating the ResourceBundle.Control
class, except that this method returns a singleton.
Parameters | |
---|---|
formats |
MutableList<String!>!: the formats to be returned by the ResourceBundle.Control.getFormats method |
Return | |
---|---|
ResourceBundle.Control! |
a ResourceBundle.Control supporting the specified formats |
Exceptions | |
---|---|
java.lang.NullPointerException |
if formats is null |
java.lang.IllegalArgumentException |
if formats is unknown |
getFallbackLocale
open fun getFallbackLocale(
baseName: String!,
locale: Locale!
): Locale!
Returns a Locale
to be used as a fallback locale for further resource bundle searches by the ResourceBundle.getBundle
factory method. This method is called from the factory method every time when no resulting resource bundle has been found for baseName
and locale
, where locale is either the parameter for ResourceBundle.getBundle
or the previous fallback locale returned by this method.
The method returns null
if no further fallback search is desired.
The default implementation returns the default Locale
if the given locale
isn't the default one. Otherwise, null
is returned.
Parameters | |
---|---|
baseName |
String!: the base name of the resource bundle, a fully qualified class name for which ResourceBundle.getBundle has been unable to find any resource bundles (except for the base bundle) |
locale |
Locale!: the Locale for which ResourceBundle.getBundle has been unable to find any resource bundles (except for the base bundle) |
Return | |
---|---|
Locale! |
a Locale for the fallback search, or null if no further fallback search is desired. |
Exceptions | |
---|---|
java.lang.NullPointerException |
if baseName or locale is null |
getFormats
open fun getFormats(baseName: String!): MutableList<String!>!
Returns a List
of String
s containing formats to be used to load resource bundles for the given baseName
. The ResourceBundle.getBundle
factory method tries to load resource bundles with formats in the order specified by the list. The list returned by this method must have at least one String
. The predefined formats are "java.class"
for class-based resource bundles and "java.properties"
for properties-based ones. Strings starting with "java."
are reserved for future extensions and must not be used by application-defined formats.
It is not a requirement to return an immutable (unmodifiable) List
. However, the returned List
must not be mutated after it has been returned by getFormats
.
The default implementation returns FORMAT_DEFAULT
so that the ResourceBundle.getBundle
factory method looks up first class-based resource bundles, then properties-based ones.
Parameters | |
---|---|
baseName |
String!: the base name of the resource bundle, a fully qualified class name |
Return | |
---|---|
MutableList<String!>! |
a List of String s containing formats for loading resource bundles. |
Exceptions | |
---|---|
java.lang.NullPointerException |
if baseName is null |
getNoFallbackControl
static fun getNoFallbackControl(formats: MutableList<String!>!): ResourceBundle.Control!
Returns a ResourceBundle.Control
in which the getFormats
method returns the specified formats
and the getFallbackLocale
method returns null
. The formats
must be equal to one of Control#FORMAT_PROPERTIES
, java.util.ResourceBundle.Control#FORMAT_CLASS
or Control#FORMAT_DEFAULT
. ResourceBundle.Control
instances returned by this method are singletons and thread-safe.
Parameters | |
---|---|
formats |
MutableList<String!>!: the formats to be returned by the ResourceBundle.Control.getFormats method |
Return | |
---|---|
ResourceBundle.Control! |
a ResourceBundle.Control supporting the specified formats with no fallback Locale support |
Exceptions | |
---|---|
java.lang.NullPointerException |
if formats is null |
java.lang.IllegalArgumentException |
if formats is unknown |
getTimeToLive
open fun getTimeToLive(
baseName: String!,
locale: Locale!
): Long
Returns the time-to-live (TTL) value for resource bundles that are loaded under this ResourceBundle.Control
. Positive time-to-live values specify the number of milliseconds a bundle can remain in the cache without being validated against the source data from which it was constructed. The value 0 indicates that a bundle must be validated each time it is retrieved from the cache. TTL_DONT_CACHE
specifies that loaded resource bundles are not put in the cache. TTL_NO_EXPIRATION_CONTROL
specifies that loaded resource bundles are put in the cache with no expiration control.
The expiration affects only the bundle loading process by the ResourceBundle.getBundle
factory method. That is, if the factory method finds a resource bundle in the cache that has expired, the factory method calls the needsReload
method to determine whether the resource bundle needs to be reloaded. If needsReload
returns true
, the cached resource bundle instance is removed from the cache. Otherwise, the instance stays in the cache, updated with the new TTL value returned by this method.
All cached resource bundles are subject to removal from the cache due to memory constraints of the runtime environment. Returning a large positive value doesn't mean to lock loaded resource bundles in the cache.
The default implementation returns TTL_NO_EXPIRATION_CONTROL
.
Parameters | |
---|---|
baseName |
String!: the base name of the resource bundle for which the expiration value is specified. |
locale |
Locale!: the locale of the resource bundle for which the expiration value is specified. |
Return | |
---|---|
Long |
the time (0 or a positive millisecond offset from the cached time) to get loaded bundles expired in the cache, TTL_NO_EXPIRATION_CONTROL to disable the expiration control, or TTL_DONT_CACHE to disable caching. |
Exceptions | |
---|---|
java.lang.NullPointerException |
if baseName or locale is null |
needsReload
open fun needsReload(
baseName: String!,
locale: Locale!,
format: String!,
loader: ClassLoader!,
bundle: ResourceBundle!,
loadTime: Long
): Boolean
Determines if the expired bundle
in the cache needs to be reloaded based on the loading time given by loadTime
or some other criteria. The method returns true
if reloading is required; false
otherwise. loadTime
is a millisecond offset since the Calendar
Epoch.
The calling ResourceBundle.getBundle
factory method calls this method on the ResourceBundle.Control
instance used for its current invocation, not on the instance used in the invocation that originally loaded the resource bundle.
The default implementation compares loadTime
and the last modified time of the source data of the resource bundle. If it's determined that the source data has been modified since loadTime
, true
is returned. Otherwise, false
is returned. This implementation assumes that the given format
is the same string as its file suffix if it's not one of the default formats, "java.class"
or "java.properties"
.
Parameters | |
---|---|
baseName |
String!: the base bundle name of the resource bundle, a fully qualified class name |
locale |
Locale!: the locale for which the resource bundle should be instantiated |
format |
String!: the resource bundle format to be loaded |
loader |
ClassLoader!: the ClassLoader to use to load the bundle |
bundle |
ResourceBundle!: the resource bundle instance that has been expired in the cache |
loadTime |
Long: the time when bundle was loaded and put in the cache |
Return | |
---|---|
Boolean |
true if the expired bundle needs to be reloaded; false otherwise. |
Exceptions | |
---|---|
java.lang.NullPointerException |
if baseName , locale , format , loader , or bundle is null |
newBundle
open fun newBundle(
baseName: String!,
locale: Locale!,
format: String!,
loader: ClassLoader!,
reload: Boolean
): ResourceBundle!
Instantiates a resource bundle for the given bundle name of the given format and locale, using the given class loader if necessary. This method returns null
if there is no resource bundle available for the given parameters. If a resource bundle can't be instantiated due to an unexpected error, the error must be reported by throwing an Error
or Exception
rather than simply returning null
.
If the reload
flag is true
, it indicates that this method is being called because the previously loaded resource bundle has expired.
The default implementation instantiates a ResourceBundle
as follows.
- The bundle name is obtained by calling
toBundleName(baseName,
. - If
format
is"java.class"
, theClass
specified by the bundle name is loaded with the given class loader. If theClass
is found and accessible then theResourceBundle
is instantiated. The resource bundle is accessible if the package of the bundle class file is open unconditionally; otherwise,IllegalAccessException
will be thrown. Note that thereload
flag is ignored for loading class-based resource bundles in this default implementation. - If
format
is"java.properties"
,toResourceName(bundlename,
is called to get the resource name. Ifreload
istrue
,load.getResource
is called to get aURL
for creating aURLConnection
. ThisURLConnection
is used to caches of the underlying resource loading layers, and toInputStream
. Otherwise,loader.getResourceAsStream
is called to get anInputStream
. Then, aPropertyResourceBundle
is constructed with theInputStream
. - If
format
is neither"java.class"
nor"java.properties"
, anIllegalArgumentException
is thrown.
Parameters | |
---|---|
baseName |
String!: the base bundle name of the resource bundle, a fully qualified class name |
locale |
Locale!: the locale for which the resource bundle should be instantiated |
format |
String!: the resource bundle format to be loaded |
loader |
ClassLoader!: the ClassLoader to use to load the bundle |
reload |
Boolean: the flag to indicate bundle reloading; true if reloading an expired resource bundle, false otherwise |
Return | |
---|---|
ResourceBundle! |
the resource bundle instance, or null if none could be found. |
Exceptions | |
---|---|
java.lang.NullPointerException |
if bundleName , locale , format , or loader is null , or if null is returned by toBundleName |
java.lang.IllegalArgumentException |
if format is unknown, or if the resource found for the given parameters contains malformed data. |
java.lang.ClassCastException |
if the loaded class cannot be cast to ResourceBundle |
java.lang.IllegalAccessException |
if the class or its nullary constructor is not accessible. |
java.lang.InstantiationException |
if the instantiation of a class fails for some other reason. |
java.lang.ExceptionInInitializerError |
if the initialization provoked by this method fails. |
java.lang.SecurityException |
If a security manager is present and creation of new instances is denied. See Class#newInstance() for details. |
java.io.IOException |
if an error occurred when reading resources using any I/O operations |
toBundleName
open fun toBundleName(
baseName: String!,
locale: Locale!
): String!
Converts the given and to the bundle name. This method is called from the default implementation of the newBundle
and needsReload
methods.
This implementation returns the following value:
baseName + "_" + language + "_" + script + "_" + country + "_" + variant
language
, script
, country
, and variant
are the language, script, country, and variant values of locale
, respectively. Final component values that are empty Strings are omitted along with the preceding '_'. When the script is empty, the script value is omitted along with the preceding '_'. If all of the values are empty strings, then baseName
is returned.
For example, if baseName
is "baseName"
and locale
is Locale("ja", "", "XX")
, then "baseName_ja_ _XX"
is returned. If the given locale is Locale("en")
, then "baseName_en"
is returned.
Overriding this method allows applications to use different conventions in the organization and packaging of localized resources.
Parameters | |
---|---|
baseName |
String!: the base name of the resource bundle, a fully qualified class name |
locale |
Locale!: the locale for which a resource bundle should be loaded |
Return | |
---|---|
String! |
the bundle name for the resource bundle |
Exceptions | |
---|---|
java.lang.NullPointerException |
if baseName or locale is null |
toResourceName
fun toResourceName(
bundleName: String!,
suffix: String!
): String!
Converts the given bundleName
to the form required by the ClassLoader.getResource
method by replacing all occurrences of '.'
in bundleName
with '/'
and appending a '.'
and the given file suffix
. For example, if bundleName
is "foo.bar.MyResources_ja_JP"
and suffix
is "properties"
, then "foo/bar/MyResources_ja_JP.properties"
is returned.
Parameters | |
---|---|
bundleName |
String!: the bundle name |
suffix |
String!: the file type suffix |
Return | |
---|---|
String! |
the converted resource name |
Exceptions | |
---|---|
java.lang.NullPointerException |
if bundleName or suffix is null |
Properties
FORMAT_CLASS
static val FORMAT_CLASS: MutableList<String!>!
The class-only format List
containing "java.class"
. This List
is unmodifiable.
See Also
FORMAT_DEFAULT
static val FORMAT_DEFAULT: MutableList<String!>!
The default format List
, which contains the strings "java.class"
and "java.properties"
, in this order. This List
is unmodifiable.
See Also
FORMAT_PROPERTIES
static val FORMAT_PROPERTIES: MutableList<String!>!
The properties-only format List
containing "java.properties"
. This List
is unmodifiable.
See Also