velosurf.web.l10n
Class LocalizationFilter

java.lang.Object
  velosurf.web.l10n.LocalizationFilter

All Implemented Interfaces:

javax.servlet.Filter

public class LocalizationFilter
extends java.lang.Object
implements javax.servlet.Filter

Localization filter. It's goal is to redirect or forward incoming unlocalized http requests (depending on the choosen method, FORWARD or REDIRECT) towards an address taking into account the best match between requested locales and supported locales, and also to deduce the locale from URLS (when REDIRECT is used).

Optional init parameters:

• supported-locales: comma separated list of supported locales ; if not provided, there is an attempt to programatically determine it⁽¹⁾. No default value provided.
• default-locale: the locale to be used by default (after four checks: the incoming URI, the session, cookies, and the request headers). No default value provided.
• localization-method: forward or redirect, default is redirect.
• match-host & rewrite-host: not yet implemented.⁽²⁾
• match-uri & rewrite-uri: the regular expression against which an unlocalized uri is matched, and the replacement uri, where @ represents the locale and $1, $2, ... the matched sub-patterns. Defaults are ^/(.*)$ for match-uri and /@/$1 for rewrite-uri.(2)
• match-query-string & rewrite-query-string: not yet implemented.(2)
• match-url & rewrite-url: not yet implemented.(2)

(1) for now, to find supported locales if this parameter is not provided, the filter try to use the rewrite-uri param and to check for the existence of corresponding directories (only if the rewriting string contains a pattern like '/@/', that is if you use directories to store localized sites).

(2) The different match- and rewrite- parameters pairs are mutually exclusive. All matches are case-insensitive.

When the redirect method is used, these supplementary parameters (mutually exclusive) allow the filter to know whether or not an incoming URI is localized.

• inspect-host: not yet implemented.
• inspect-uri: default is ^/(.+)(?:/|$).
• inspect-query-string: not yet implemented.
• inspect-url: not yet implemented.

Author:

Claude Brisson

Field Summary

private javax.servlet.FilterConfig	config filter config.
private static java.lang.String	defaultInspectUri default inspect uri.
private java.util.Locale	defaultLocale default locale.
private static java.lang.String	defaultMatchUri default match uri.
private static java.lang.String	defaultRewriteUri default rewrite uri.
private static int	FORWARD forward method constant.
private java.util.regex.Pattern	inspectUri inspect uri.
private int	l10nMethod localization method.
private java.util.regex.Pattern	matchUri match uri.
private static int	REDIRECT redirect method constant.
private java.lang.String	rewriteUri rewrite uri
private static int	SECONDS_IN_YEAR seconds in year (for setting cookies age).
private java.util.List<java.util.Locale>	supportedLocales supported locales.

Constructor Summary

LocalizationFilter()

Method Summary

void	destroy() Destroy the filter.
void	doFilter(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse, javax.servlet.FilterChain chain) Filtering.
private void	findSupportedLocales(javax.servlet.FilterConfig config) Find supported locales.
private java.lang.String	getInitParameter(java.lang.String key) Helper function.
private java.lang.String	getInitParameter(java.lang.String key, java.lang.String defaultValue) Helper function.
private java.util.Locale	getMatchedLocale(java.lang.String candidate) get matched locale.
private java.util.Locale	getPreferredLocale(java.util.List<java.util.Locale> requestedLocales) Get preferred locale.
private java.util.List<java.util.Locale>	getRequestedLocales(javax.servlet.http.HttpServletRequest request) get the list of requested locales.
private java.util.List<java.util.Locale>	guessSupportedLocales(javax.servlet.ServletContext ctx, java.lang.String path) Guess supported locales.
void	init(javax.servlet.FilterConfig config) initialization.

Methods inherited from class java.lang.Object

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

Field Detail

config

private javax.servlet.FilterConfig config

filter config.

supportedLocales

private java.util.List<java.util.Locale> supportedLocales

supported locales.

defaultLocale

private java.util.Locale defaultLocale

default locale.

SECONDS_IN_YEAR

private static int SECONDS_IN_YEAR

seconds in year (for setting cookies age).

defaultMatchUri

private static java.lang.String defaultMatchUri

default match uri.

defaultRewriteUri

private static java.lang.String defaultRewriteUri

default rewrite uri.

defaultInspectUri

private static java.lang.String defaultInspectUri

default inspect uri.

matchUri

private java.util.regex.Pattern matchUri

match uri.

rewriteUri

private java.lang.String rewriteUri

rewrite uri

inspectUri

private java.util.regex.Pattern inspectUri

inspect uri.

FORWARD

private static final int FORWARD

forward method constant.

See Also:

Constant Field Values

REDIRECT

private static final int REDIRECT

redirect method constant.

See Also:

Constant Field Values

l10nMethod

private int l10nMethod

localization method.

Constructor Detail

LocalizationFilter

public LocalizationFilter()

Method Detail

init

public void init(javax.servlet.FilterConfig config)
          throws javax.servlet.ServletException

initialization.

Specified by:

init in interface javax.servlet.Filter

Parameters:

config - filter config

Throws:

javax.servlet.ServletException

doFilter

public void doFilter(javax.servlet.ServletRequest servletRequest,
                     javax.servlet.ServletResponse servletResponse,
                     javax.servlet.FilterChain chain)
              throws java.io.IOException,
                     javax.servlet.ServletException

Filtering.

Specified by:

doFilter in interface javax.servlet.Filter

Parameters:

servletRequest - request

servletResponse - response

chain - filter chain

Throws:

java.io.IOException

javax.servlet.ServletException

findSupportedLocales

private void findSupportedLocales(javax.servlet.FilterConfig config)

Find supported locales.

Parameters:

config - filter config

getInitParameter

private java.lang.String getInitParameter(java.lang.String key)

Helper function.

Parameters:

key -

Returns:

init-parameter

getInitParameter

private java.lang.String getInitParameter(java.lang.String key,
                                          java.lang.String defaultValue)

Helper function.

Parameters:

key -

defaultValue -

Returns:

init-parameter

destroy

public void destroy()

Destroy the filter.

Specified by:

destroy in interface javax.servlet.Filter

guessSupportedLocales

private java.util.List<java.util.Locale> guessSupportedLocales(javax.servlet.ServletContext ctx,
                                                               java.lang.String path)

Guess supported locales.

Parameters:

ctx - servlet context

path - path

Returns:

list of locales

getRequestedLocales

private java.util.List<java.util.Locale> getRequestedLocales(javax.servlet.http.HttpServletRequest request)

get the list of requested locales.

Parameters:

request - request

Returns:

list of locales

getMatchedLocale

private java.util.Locale getMatchedLocale(java.lang.String candidate)

get matched locale.

Parameters:

candidate - candidate

Returns:

locale

getPreferredLocale

private java.util.Locale getPreferredLocale(java.util.List<java.util.Locale> requestedLocales)

Get preferred locale.

Parameters:

requestedLocales - requested locales

Returns:

preferred locale