com.oreilly.servlet

Class LocaleNegotiator

java.lang.Object

com.oreilly.servlet.LocaleNegotiator

public class LocaleNegotiator
extends java.lang.Object

A class to aid in servlet internationalization. It determines, from a client request, the best charset, locale, and resource bundle to use with the response.

LocaleNegotiator works by scanning through the client's language preferences (sent by browsers in the Accept-Language header) looking for any language for which there exists is a corresponding resource bundle. When it finds a correspondence, it uses the LocaleToCharsetMap class to determine the charset. If there's any problem, it tries to fall back to US English. The logic currently ignores the client's charset preferences (sent in the Accept-Charset header).

It can be used like this:

 String bundleName = "BundleName";
 String acceptLanguage = req.getHeader("Accept-Language");
 String acceptCharset = req.getHeader("Accept-Charset");
  
 LocaleNegotiator negotiator =
   new LocaleNegotiator(bundleName, acceptLanguage, acceptCharset);
  
 Locale locale = negotiator.getLocale();
 String charset = negotiator.getCharset();
 ResourceBundle bundle = negotiator.getBundle();  // may be null
  
 res.setContentType("text/plain; charset=" + charset);
 res.setHeader("Content-Language", locale.getLanguage());
 res.setHeader("Vary", "Accept-Language");
  
 PrintWriter out = res.getWriter();
  
 out.println(bundle.getString("resource"));
 

See Also:

LocaleToCharsetMap

Constructor Summary

Constructors

Constructor and Description
LocaleNegotiator(java.lang.String bundleName, java.lang.String languages, java.lang.String charsets) Constructs a new LocaleNegotiator for the given bundle name, language list, and charset list.

Method Summary

Modifier and Type	Method and Description
java.util.ResourceBundle	getBundle() Gets the chosen bundle.
java.lang.String	getCharset() Gets the chosen charset.
protected java.lang.String	getCharsetForLocale(java.util.Locale loc, java.lang.String charsets) Gets the best charset for a given locale, selecting from a charset list.
java.util.Locale	getLocale() Gets the chosen locale.

Methods inherited from class java.lang.Object

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

Constructor Detail

LocaleNegotiator

public LocaleNegotiator(java.lang.String bundleName,
                        java.lang.String languages,
                        java.lang.String charsets)

Constructs a new LocaleNegotiator for the given bundle name, language list, and charset list.

Parameters:

bundleName - the resource bundle name

languages - the Accept-Language header

charsets - the Accept-Charset header

Method Detail

getBundle

public java.util.ResourceBundle getBundle()

Gets the chosen bundle.

Returns:

the chosen bundle

getLocale

public java.util.Locale getLocale()

Gets the chosen locale.

Returns:

the chosen locale

getCharset

public java.lang.String getCharset()

Gets the chosen charset.

Returns:

the chosen charset

getCharsetForLocale

protected java.lang.String getCharsetForLocale(java.util.Locale loc,
                                               java.lang.String charsets)

Gets the best charset for a given locale, selecting from a charset list. Currently ignores the charset list. Subclasses can override this method to take the list into account.

Parameters:

loc - the locale

charsets - a comma-separated charset list

Returns:

the best charset for the given locale from the given list