java.util.PropertyResourceBundle Maven / Gradle / Ivy
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*
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/*
* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
* (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
*
* The original version of this source code and documentation
* is copyrighted and owned by Taligent, Inc., a wholly-owned
* subsidiary of IBM. These materials are provided under terms
* of a License Agreement between Taligent and Sun. This technology
* is protected by multiple US and International patents.
*
* This notice and attribution to Taligent may not be removed.
* Taligent is a registered trademark of Taligent, Inc.
*/
package java.util;
import java.io.InputStream;
import java.io.Reader;
import java.io.IOException;
/**
* PropertyResourceBundle is a concrete subclass of
* ResourceBundle that manages resources for a locale
* using a set of static strings from a property file. See
* {@link ResourceBundle 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
* {@link ResourceBundle#getBundle(java.lang.String, java.util.Locale, java.lang.ClassLoader) 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
*
*
*
*
* 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 ISO-8859-1. In that case, 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.
*
* @see ResourceBundle
* @see ListResourceBundle
* @see Properties
* @since JDK1.1
*/
public class PropertyResourceBundle extends ResourceBundle {
/**
* Creates a property resource bundle from an {@link java.io.InputStream
* InputStream}. The property file read with this constructor
* must be encoded in ISO-8859-1.
*
* @param stream an InputStream that represents a property file
* to read from.
* @throws IOException if an I/O error occurs
* @throws NullPointerException if stream is null
*/
public PropertyResourceBundle (InputStream stream) throws IOException {
Properties properties = new Properties();
properties.load(stream);
lookup = new HashMap(properties);
}
/**
* Creates a property resource bundle from a {@link java.io.Reader
* Reader}. Unlike the constructor
* {@link #PropertyResourceBundle(java.io.InputStream) PropertyResourceBundle(InputStream)},
* there is no limitation as to the encoding of the input property file.
*
* @param reader a Reader that represents a property file to
* read from.
* @throws IOException if an I/O error occurs
* @throws NullPointerException if reader is null
* @since 1.6
*/
public PropertyResourceBundle (Reader reader) throws IOException {
Properties properties = new Properties();
properties.load(reader);
lookup = new HashMap(properties);
}
// Implements java.util.ResourceBundle.handleGetObject; inherits javadoc specification.
public Object handleGetObject(String key) {
if (key == null) {
throw new NullPointerException();
}
return lookup.get(key);
}
/**
* Returns an Enumeration of the keys contained in
* this ResourceBundle and its parent bundles.
*
* @return an Enumeration of the keys contained in
* this ResourceBundle and its parent bundles.
* @see #keySet()
*/
public Enumeration getKeys() {
ResourceBundle parent = this.parent;
return new ResourceBundleEnumeration(lookup.keySet(),
(parent != null) ? parent.getKeys() : null);
}
/**
* Returns a Set of the keys contained
* only in this ResourceBundle.
*
* @return a Set of the keys contained only in this
* ResourceBundle
* @since 1.6
* @see #keySet()
*/
protected Set handleKeySet() {
return lookup.keySet();
}
// ==================privates====================
private Map lookup;
/**
* Implements an Enumeration that combines elements from a Set and
* an Enumeration. Used by ListResourceBundle and PropertyResourceBundle.
*/
static class ResourceBundleEnumeration implements Enumeration {
Set set;
Iterator iterator;
Enumeration enumeration; // may remain null
/**
* Constructs a resource bundle enumeration.
* @param set an set providing some elements of the enumeration
* @param enumeration an enumeration providing more elements of the enumeration.
* enumeration may be null.
*/
public ResourceBundleEnumeration(Set set, Enumeration enumeration) {
this.set = set;
this.iterator = set.iterator();
this.enumeration = enumeration;
}
String next = null;
public boolean hasMoreElements() {
if (next == null) {
if (iterator.hasNext()) {
next = iterator.next();
} else if (enumeration != null) {
while (next == null && enumeration.hasMoreElements()) {
next = enumeration.nextElement();
if (set.contains(next)) {
next = null;
}
}
}
}
return next != null;
}
public String nextElement() {
if (hasMoreElements()) {
String result = next;
next = null;
return result;
} else {
throw new NoSuchElementException();
}
}
}
}