net.sourceforge.stripes.localization

Class DefaultLocalePicker

java.lang.Object

net.sourceforge.stripes.localization.DefaultLocalePicker

All Implemented Interfaces:

ConfigurableComponent, LocalePicker

public class DefaultLocalePicker
extends Object
implements LocalePicker

Default locale picker that uses a comma separated list of locales in the servlet init parameters to determine the set of locales that are supported by the application. Then at request time matches the user's preference order list as specified by the headers included in the request until it finds one of those locales in the system list. If a match cannot be found, the first locale in the system list will be picked. If there is no list of configured locales then the picker will default the list to a one entry list containing the system locale.

Locales are hierarchical, with up to three levels designating language, country and variant. Only the first level (language) is required. To provide the best match possible the DefaultLocalePicker tracks the one-level matches, two-level matches and three-level matches. If a three level match is found, it will be returned. If not the first two-level match will be returned if one was found. If not, the first one-level match will be returned. If not even a one-level match is found, the first locale supported by the system is returned.

Author:

Tim Fennell

Field Summary

Fields

Modifier and Type	Field and Description
protected Configuration	configuration Stores a reference to the configuration passed in at initialization.
protected Map<Locale,String>	encodings Contains a map of Locale to preferred character encoding.
static String	LOCALE_LIST The configuration parameter that is used to lookup a comma separated list of locales that the system supports.
protected List<Locale>	locales Stores the configured set of Locales that the system supports, looked up at init time.

Constructor Summary

Constructors

Constructor and Description
DefaultLocalePicker()

Method Summary

Methods

Modifier and Type	Method and Description
void	init(Configuration configuration) Attempts to read the
String	pickCharacterEncoding(HttpServletRequest request, Locale locale) Returns the character encoding to use for the request and locale if one has been specified in the configuration.
Locale	pickLocale(HttpServletRequest request) Uses a preference matching algorithm to pick a Locale for the user's request.

Methods inherited from class java.lang.Object

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

Field Detail

LOCALE_LIST

public static final String LOCALE_LIST

The configuration parameter that is used to lookup a comma separated list of locales that the system supports.

See Also:

Constant Field Values

configuration

protected Configuration configuration

Stores a reference to the configuration passed in at initialization.

locales

protected List<Locale> locales

Stores the configured set of Locales that the system supports, looked up at init time.

encodings

protected Map<Locale,String> encodings

Contains a map of Locale to preferred character encoding.

Constructor Detail

DefaultLocalePicker

public DefaultLocalePicker()

Method Detail

init

public void init(Configuration configuration)
          throws Exception

Attempts to read the

Specified by:

init in interface ConfigurableComponent

Parameters:

configuration -

Throws:

Exception

pickLocale

public Locale pickLocale(HttpServletRequest request)

Uses a preference matching algorithm to pick a Locale for the user's request. Iterates through the user's acceptable list of Locales, matching them against the system list. On the way through the list records the first Locale to match on Language, and the first locale to match on both Language and Country. If a match is found for all three, Language, Country and Variant, it will be returned. If no three-way match is found the first two-way match found will be returned. If no two-way match way found the first one-way match found will be returned. If no one way match was found, the default system locale will be returned.

Specified by:

pickLocale in interface LocalePicker

Parameters:

request - the request being processed

Returns:

a Locale to use in processing the request

pickCharacterEncoding

public String pickCharacterEncoding(HttpServletRequest request,
                           Locale locale)

Returns the character encoding to use for the request and locale if one has been specified in the configuration. If no value has been specified, returns null.

Specified by:

pickCharacterEncoding in interface LocalePicker

Parameters:

request - the current request

locale - the locale picked for the request

Returns:

a valid character encoding or null