16.3. Labels

⁠16.3. Labels

JSF supports the internationalization of user interface labels and descriptive text with the <f:loadBundle />. In Seam applications, you can either take this approach, or use the Seam messages component to display templated labels with embedded EL expressions.

⁠16.3.1. Defining labels

Make your internationalized labels available with Seam's java.util.ResourceBundle, available to the application as a org.jboss.seam.core.resourceBundle. By default, Seam uses a resource bundle named messages, so you will need to define your labels in files named messages.properties, messages_en.properties, messages_en_AU.properties, etc. These files usually belong in the WEB-INF/classes directory.

So, in messages_en.properties:

Hello=Hello

And in messages_en_AU.properties:

Hello=G'day

You can select a different name for the resource bundle by setting the Seam configuration property named org.jboss.seam.core.resourceLoader.bundleNames. You can even specify a list of resource bundle names to be searched (depth first) for messages.

<core:resource-loader> 
  <core:bundle-names> 
    <value>mycompany_messages</value> 
    <value>standard_messages</value>       
  </core:bundle-names> 
</core:resource-loader>

To define a message for one particular page, specify it in a resource bundle with the same name as the JSF view ID, with the leading / and trailing file extension removed. So, we could put our message in welcome/hello_en.properties if we only needed to display the message on /welcome/hello.xhtml.

You can even specify an explicit bundle name in pages.xml:

<page view-id="/welcome/hello.xhtml" bundle="HelloMessages"/>

Then we could use messages defined in HelloMessages.properties on /welcome/hello.xhtml.

⁠16.3.2. Displaying labels

If you define your labels with the Seam resource bundle, you can use them without having to type <f:loadBundle... /> on each page. Instead, you can type:

<h:outputText value="#{messages['Hello']}"/>

or:

<h:outputText value="#{messages.Hello}"/>

Even better, the messages themselves may contain EL expressions:

Hello=Hello, #{user.firstName} #{user.lastName}

Hello=G'day, #{user.firstName}

You can even use the messages in your code:

@In private Map<String, String> messages;

@In("#{messages['Hello']}") private String helloMessage;

⁠16.3.3. Faces messages

The facesMessages component is a convenient way to display success or failure messages to the user. The functionality we just described also works for Faces messages:

@Name("hello") 
@Stateless 
public class HelloBean implements Hello { 
  @In FacesMessages facesMessages; 
  public String sayIt() { 
    facesMessages.addFromResourceBundle("Hello"); 
  } 
}

This will display Hello, Gavin King or G'day, Gavin, depending upon the user's locale.