atg.core.i18n
Class LayeredResourceBundle

java.lang.Object
  atg.core.i18n.LayeredResourceBundle

public class LayeredResourceBundle
extends java.lang.Object

A class capable of creating layered resource bundles. Layered resource bundles function similiarly to Nucleus component properties files, where it is possible to override a property definitions by creating a properties file in the same location as the original, but in a different configuration layer.

Layered resource bundles work by layering properties files contained in different class paths. Properties definitions in files that appear earlier in the classpath will override property definitions which appear later in the classpath.

This class attempts to be a drop-in replacement for calls to ResourceBundle.getBundle(). It implements allowing classes earlier in the classpath to override or extend individual property values, but allows values from later in the classpath to "bleed through." Thus it mimics the same behavior that Nucleus properties have.

The known limitations of LayeredResourceBundle are:

• It only supports properties file format for resources, not XML format
• It does not know the ClassLoader of the calling class.
• LayeredResourceBundle.getBundle() must be called for that bundle prior to any other calls to ResourceBundle.getBundle() for the same bundle name. Otherwise, a non-layered bundle will be returned.
• LayeredResourceBundle is not compatible with the "-collapse-class-path" option of the /bin/runAssembler command.

ResourceBundle.getBundle() uses a non-public native call to get the ClassLoader of the call of the ResourceBundle.getBundle() method. Since LayeredResourceBundle does not have access to that call, you may need to pass in your ClassLoader explicitly. So, you may need invoke ResourceBundle.getBundle(String pBaseName, Locale pLocale, ClassLoader pLoader) and pass in this.getClass().getClassLoader() for the ClassLoader argument.

The LayeredResourceBundle re-uses a maximal amount of ResourceBundle.getBundle()'s code. Instead of re-implementing all the ResourceBundle logic, it creates a child ClassLoader that returns a special InputStream for .properties file. That CompositeInputStream concatenates all the properties files from the classpath so that the final result of the Properties file allows values to bleed through properly.

Nested Class Summary

static interface

LayeredResourceBundle.BaseResourceStreamClassLoader An interface a ClassLoader can implement for returning the base input stream for a resource.

Field Summary

static java.lang.String

CLASS_VERSION Class version string

Constructor Summary

LayeredResourceBundle()

Method Summary

static java.util.ResourceBundle	getBundle(java.lang.String pBaseName) Gets a layered resource bundle using the specified base name, the default locale, and the LayeredResourceBundle's class loader.
static java.util.ResourceBundle	getBundle(java.lang.String pBaseName, java.util.Locale pLocale) Gets a layered resource bundle using the specified base name and locale, and the LayeredResourceBundle's class loader.
static java.util.ResourceBundle	getBundle(java.lang.String pBaseName, java.util.Locale pLocale, java.lang.ClassLoader pLoader) Gets a resource bundle using the specified base name, locale, and class loader.
static void	main(java.lang.String[] pArgs)

Methods inherited from class java.lang.Object

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

Field Detail

CLASS_VERSION

public static java.lang.String CLASS_VERSION

Class version string

Constructor Detail

LayeredResourceBundle

public LayeredResourceBundle()

Method Detail

getBundle

public static final java.util.ResourceBundle getBundle(java.lang.String pBaseName)

Gets a layered resource bundle using the specified base name, the default locale, and the LayeredResourceBundle's class loader. Calling this method is equivalent to calling getBundle(baseName, Locale.getDefault(), LayeredResourceBundle.class.getClassLoader()).

Parameters:

pBaseName - 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

Throws:

java.lang.NullPointerException - if baseName is null

MissingResourceException - if no resource bundle for the specified base name can be found

See Also:

ResourceBundle.getBundle(String)

getBundle

public static final java.util.ResourceBundle getBundle(java.lang.String pBaseName,
                                                       java.util.Locale pLocale)

Gets a layered resource bundle using the specified base name and locale, and the LayeredResourceBundle's class loader. Calling this method is equivalent to calling getBundle(baseName, locale, LayeredResourceBundle.class.getClassLoader()).

Parameters:

pBaseName - the base name of the resource bundle, a fully qualified class name

pLocale - the locale for which a resource bundle is desired

Returns:

a resource bundle for the given base name and locale

Throws:

java.lang.NullPointerException - if baseName or locale is null

MissingResourceException - if no resource bundle for the specified base name can be found

See Also:

ResourceBundle.getBundle(String,Locale)

getBundle

public static java.util.ResourceBundle getBundle(java.lang.String pBaseName,
                                                 java.util.Locale pLocale,
                                                 java.lang.ClassLoader pLoader)

Gets a resource bundle using the specified base name, locale, and class loader. See ResourceBundle.getBundle(String,Locale,ClassLoader) for a full description of the search path used to obtain a resource bundle. This is further augmented by a pre-processing step, where all resource bundle properties files with a given name will be collapsed into a single file. The files will be combine in such a way that entries which come early in the classpath will appear at the end of the input stream. The ResourceBundle code will then create a Properties instance using that composite input stream. Given that later entries in the Properties map will overwrite earlier entries, the result will be a ResourceBundle whose values can be overriden by prepending a sparse properties file, containing only the values to be altered, to the beginning of the class-path.

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

Throws:

java.lang.NullPointerException - if baseName, locale, or loader is null

MissingResourceException - if no resource bundle for the specified base name can be found

See Also:

ResourceBundle.getBundle(String,Locale,ClassLoader)

main

public static void main(java.lang.String[] pArgs)