You can specify the strings appearing in a web application using a properties file. The string properties can be accessed in XHTML files using EL bundle properties expressions. This makes it easier to change the strings.

JSF also provides an internationalization mechanism that selects a properties file from a message bundle based on locale preference information sent by a browser. To use this mechanism you must declare the message bundle in a configuration file.

To manage the strings displayed on pages, they can be stored in a properties file. A properties file consists of a line for each string that it defines. Each line has the form

string-name=string-value

The string-value is substituted for string-name wherever it appears in a web page.

A properties file is stored in a Java source package. It must have the .properties extension.

A string value defined in a properties file can use parameterization. This allows the string value to depend in the values of JSF beans.

A string value defined in a properties file can have parameters using {n} notation, where n is the parameter number starting with 0. In this simple form the parameter supplied by a web page is simply substituted for the "{n}".

The value of the string can depend on the parameter in more complex ways. If you want to display parameterized text about counts with good grammar you need a string definition like the following.

carCount=You have {0,choice,0#no cars|1#one car|2#{0} cars}.

• The "0" immediately after the brace specifies the parameter number.
• The "choice" says that the string value depends on the parameter value.
• The text following "0#" up to the first "|" is the string value when the parameter has value 0.
• The text following "1#" up to the second "|" is the string value when the parameter has value 1.
• The text following "2#" is the string value when the parameter has value 2 or more. Note that this uses the simple form of parameterization.

This leads to the following values for the carCount string.

Parameter 0 Value	carCount Value
0	You have no cars.
1	You have one car.
2	You have 2 cars.
80	You have 80 cars.

A message bundle is a group of properties files, all in the same source package. There should be one properties file for each supported locale. They all define the same string names but have different values for different locales.

The JSF framework uses a file naming convention to select the appropriate properties file. Each file name has the form file-base-name_locale-suffix.properties. The locale-suffix part is omitted for the default locale.

The bundle path has the form source-package-name.file-base-name. This path is needed in the declaration of the bundle.

You declare a message bundle in a <application> tag in the faces-config.xml file. There, the resource bundle files are specified and the bundle is given a name for use in the JSF pages.

   <application>
      <locale-config>
         <default-locale>en</default-locale>
         <supported-locale>de</supported-locale>
      </locale-config>
      <resource-bundle>
         <base-name>bundle-path</base-name>
         <var>bundle-name</var>
      </resource-bundle>
   </application>

The <locale-config> tag specifies the default locale and all other supported locales using the standard two-letter locale codes.

• the default locale (the <default-locale> subtag)
• all other supported locales (0 or more <supported-locale> subtags)

The <resource-bundle> tag specifies

• the bundle path (the <base-name> subtag)
• the name that is used to reference it in screen pages (the <var> subtag)

A string in a message bundle can be referenced with the notation #{bundle-name.string-name}, where

• bundle-name is the name given to the bundle in the faces-config.xml file and
• string-name is the name given to the string in the properties files.

When a string in a message bundle is parameterized a special tag is used to supply parameter values. This tag can contain references to bean data.

A string access in a web page can supply bean data for parameters using <f:param> tags. This tag is a subtag of a <h:outputFormat> tag as shown below.

        <h:outputFormat value="#{string-reference}">
          <f:param value="#{bean-reference}"/>
        </h:outputFormat>

The <h:outputFormat> tag should contain the same number of <f:param> tags as the number of parameters in the value for string-reference.

Use of the <f:param> tag requires declaration of the "f:" namespace in the <html> tag of the XHTML file:

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:f="http://java.sun.com/jsf/core"
      xmlns:h="http://java.sun.com/jsf/html">

The numberquiz application can be run here. To manage application strings with internationalization the application

• creates a message bundle with path name com.corejsf.messages,
• declares the message bundle to have name msgs, and
• accesses the bundle from it's screen pages.

The com.corejsf.messages bundle for the numberquiz application consists of the following two files.

Source Packages/com/corejsf/messages.properties

This is the properties file for strings for the the default locale English.

Source Packages/com/corejsf/messages_de.properties

This is the properties file for strings for the German locale. The string names are the same as in messages.properties, but their values are in German.

The locale is indicated by the "_de" in the file name. Each locale has a standard two-letter abbreviation. "de" is the abbreviation for the German locale.

Every instance of #{msgs.string-name} in index.xhtml accesses a string from the message bundle. The access to msgs.currentScore illustrates parameterized strings.