Module java.base

Package java.util

Class PropertyResourceBundle

java.lang.Object

java.util.ResourceBundle

java.util.PropertyResourceBundle

public class PropertyResourceBundle
extends ResourceBundle

PropertyResourceBundle is a concrete subclass of ResourceBundle that manages resources for a locale using a set of static strings from a property file. See ResourceBundle for more information about resource bundles.

Unlike other types of resource bundle, you don't subclass PropertyResourceBundle. Instead, you supply properties files containing the resource data. ResourceBundle.getBundle will automatically look for the appropriate properties file and create a PropertyResourceBundle that refers to it. See ResourceBundle.getBundle for a complete description of the search and instantiation strategy.

The following example shows a member of a resource bundle family with the base name "MyResources". The text defines the bundle "MyResources_de", the German member of the bundle family. This member is based on PropertyResourceBundle, and the text therefore is the content of the file "MyResources_de.properties" (a related example shows how you can add bundles to this family that are implemented as subclasses of ListResourceBundle). The keys in this example are of the form "s1" etc. The actual keys are entirely up to your choice, so long as they are the same as the keys you use in your program to retrieve the objects from the bundle. Keys are case-sensitive.

 # MessageFormat pattern
 s1=Die Platte \"{1}\" enthält {0}.

 # location of {0} in pattern
 s2=1

 # sample disk name
 s3=Meine Platte

 # first ChoiceFormat choice
 s4=keine Dateien

 # second ChoiceFormat choice
 s5=eine Datei

 # third ChoiceFormat choice
 s6={0,number} Dateien

 # sample date
 s7=3. März 1996
 

API Note:

PropertyResourceBundle can be constructed either from an InputStream or a Reader, which represents a property file. Constructing a PropertyResourceBundle instance from an InputStream requires that the input stream be encoded in UTF-8. By default, if a MalformedInputException or an UnmappableCharacterException occurs on reading the input stream, then the PropertyResourceBundle instance resets to the state before the exception, re-reads the input stream in ISO-8859-1, and continues reading. If the system property java.util.PropertyResourceBundle.encoding is set to either "ISO-8859-1" or "UTF-8", the input stream is solely read in that encoding, and throws the exception if it encounters an invalid sequence. If "ISO-8859-1" is specified, characters that cannot be represented in ISO-8859-1 encoding must be represented by Unicode Escapes as defined in section 3.3 of The Java™ Language Specification whereas the other constructor which takes a Reader does not have that limitation. Other encoding values are ignored for this system property. The system property is read and evaluated when initializing this class. Changing or removing the property has no effect after the initialization.

Implementation Requirements:

The implementation of a PropertyResourceBundle subclass must be thread-safe if it's simultaneously used by multiple threads. The default implementations of the non-abstract methods in this class are thread-safe.

Since:

1.1

See Also:

ResourceBundle, ListResourceBundle, Properties

Nested Class Summary

Nested classes/interfaces inherited from class java.util.ResourceBundle

ResourceBundle.Control

Field Summary

Fields inherited from class java.util.ResourceBundle

parent

Constructor Summary

Constructors

Constructor	Description
PropertyResourceBundle(InputStream stream)	Creates a property resource bundle from an InputStream.
PropertyResourceBundle(Reader reader)	Creates a property resource bundle from a Reader.

Method Summary

Modifier and Type	Method	Description
Enumeration<String>	getKeys()	Returns an Enumeration of the keys contained in this ResourceBundle and its parent bundles.
Object	handleGetObject(String key)	Gets an object for the given key from this resource bundle.
protected Set<String>	handleKeySet()	Returns a Set of the keys contained only in this ResourceBundle.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from class java.util.ResourceBundle

clearCache, clearCache, containsKey, getBaseBundleName, getBundle, getBundle, getBundle, getBundle, getBundle, getBundle, getBundle, getBundle, getLocale, getObject, getString, getStringArray, keySet, setParent

Constructor Detail

PropertyResourceBundle

public PropertyResourceBundle(InputStream stream)
                       throws IOException

Creates a property resource bundle from an InputStream. This constructor reads the property file in UTF-8 by default. If a MalformedInputException or an UnmappableCharacterException occurs on reading the input stream, then the PropertyResourceBundle instance resets to the state before the exception, re-reads the input stream in ISO-8859-1 and continues reading. If the system property java.util.PropertyResourceBundle.encoding is set to either "ISO-8859-1" or "UTF-8", the input stream is solely read in that encoding, and throws the exception if it encounters an invalid sequence. Other encoding values are ignored for this system property. The system property is read and evaluated when initializing this class. Changing or removing the property has no effect after the initialization.

Parameters:

stream - an InputStream that represents a property file to read from.

Throws:

IOException - if an I/O error occurs

NullPointerException - if stream is null

IllegalArgumentException - if stream contains a malformed Unicode escape sequence.

MalformedInputException - if the system property java.util.PropertyResourceBundle.encoding is set to "UTF-8" and stream contains an invalid UTF-8 byte sequence.

UnmappableCharacterException - if the system property java.util.PropertyResourceBundle.encoding is set to "UTF-8" and stream contains an unmappable UTF-8 byte sequence.

PropertyResourceBundle

public PropertyResourceBundle(Reader reader)
                       throws IOException

Creates a property resource bundle from a Reader. Unlike the constructor PropertyResourceBundle(InputStream), there is no limitation as to the encoding of the input property file.

Parameters:

reader - a Reader that represents a property file to read from.

Throws:

IOException - if an I/O error occurs

NullPointerException - if reader is null

IllegalArgumentException - if a malformed Unicode escape sequence appears from reader.

Since:

1.6

Method Detail

handleGetObject

public Object handleGetObject(String key)

Description copied from class: ResourceBundle

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.

Specified by:

handleGetObject in class ResourceBundle

Parameters:

key - the key for the desired object

Returns:

the object for the given key, or null

getKeys

public Enumeration<String> getKeys()

Returns an Enumeration of the keys contained in this ResourceBundle and its parent bundles.

Specified by:

getKeys in class ResourceBundle

Returns:

an Enumeration of the keys contained in this ResourceBundle and its parent bundles.

See Also:

ResourceBundle.keySet()

handleKeySet

protected Set<String> handleKeySet()

Returns a Set of the keys contained only in this ResourceBundle.

Overrides:

handleKeySet in class ResourceBundle

Returns:

a Set of the keys contained only in this ResourceBundle

Since:

1.6

See Also:

ResourceBundle.keySet()