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## Chapter 16. Internationalization, localization and themes

Seam makes it easy to build internationalized applications. First, let's walk through all the stages needed to internationalize and localize your app. Then we'll take a look at the components Seam bundles.

## 16.1. Internationalizing your app

A JEE application consists of many components and all of them must be configured properly for your application to be localized.

Starting at the bottom, the first step is to ensure that your database server and client is using the correct character encoding for your locale. Normally you'll want to use UTF-8. How to do this is outside the scope of this tutorial.

### 16.1.1. Application server configuration

To ensure that the application server receives the request parameters in the correct encoding from client requests you have to configure the tomcat connector. If you use Tomcat or JBoss AS, add the `URIEncoding="UTF-8"` attribute to the connector configuration. For JBoss AS 4.2 change `${JBOSS_HOME}/server/(default)/deploy/jboss-web.deployer/server.xml`:

    <Connector port="8080" URIEncoding="UTF-8"/>

There is alternative which is probably better. You can tell JBoss AS that the encoding for the request parameters will be taken from the request:

    <Connector port="8080" useBodyEncodingForURI="true"/>

### 16.1.2. Translated application strings

You'll also need localized strings for all the messages in your application (for example field labels on your views). First you need to ensure that your resource bundle is encoded using the desired character encoding. By default ASCII is used. Although ASCII is enough for many languages, it doesn't provide characters for all languages.

Resource bundles must be created in ASCII, or use Unicode escape codes to represent Unicode characters. Since you don't compile a property file to byte code, there is no way to tell the JVM which character set to use. So you must use either ASCII characters or escape characters not in the ASCII character set. You can represent a Unicode character in any Java file using \uXXXX, where XXXX is the hexidecimal representation of the character.

You can write your translation of labels (<xlink>Labels</xlink>) to your messages resource bundle in the native encoding and then convert the content of the file into the escaped format through the tool `native2ascii` provided in the JDK. This tool will convert a file written in your native encoding to one that represents non-ASCII characters as Unicode escape sequences.

Usage of this tool is described here for Java 5 or here for Java 6. For example, to convert a file from UTF-8:

    $ native2ascii -encoding UTF-8 messages_cs.properties > messages_cs_escaped.properties

### 16.1.3. Other encoding settings

We need to make sure that the view displays your localized data and messages using the correct character set and also any data submitted uses the correct encoding.

To set the display character encoding, you need to use the `<f:view locale="cs_CZ"/>` tag (here we tell JSF to use the Czech locale). You may want to change the encoding of the xml document itself if you want to embed localized strings in the xml. To do this alter the encoding attribute in xml declaration `<?xml version="1.0" encoding="UTF-8"?>` as required.

Also JSF/Facelets should submit any requests using the specified character encoding, but to make sure any requests that don't specify an encoding you can force the request encoding using a servlet filter. Configure this in `components.xml`:

    <web:character-encoding-filter encoding="UTF-8"

       override-client="true"

       url-pattern="*.seam" />

## 16.2. Locales

Each user login session has an associated instance of `java.util.Locale` (available to the application as a component named `locale`). Under normal circumstances, you won't need to do any special configuration to set the locale. Seam just delegates to JSF to determine the active locale:

- If there is a locale associated with the HTTP request (the browser locale), and that locale is in the list of supported locales from `faces-config.xml`, use that locale for the rest of the session.

- Otherwise, if a default locale was specified in the `faces-config.xml`, use that locale for the rest of the session.

- Otherwise, use the default locale of the server.

It is possible to set the locale manually via the Seam configuration properties `org.jboss.seam.international.localeSelector.language`, `org.jboss.seam.international.localeSelector.country` and `org.jboss.seam.international.localeSelector.variant`, but we can't think of any good reason to ever do this.

It is, however, useful to allow the user to set the locale manually via the application user interface. Seam provides built-in functionality for overriding the locale determined by the algorithm above. All you have to do is add the following fragment to a form in your JSP or Facelets page:

    <h:selectOneMenu value="#{localeSelector.language}">

        <f:selectItem itemLabel="English" itemValue="en"/>

        <f:selectItem itemLabel="Deutsch" itemValue="de"/>

        <f:selectItem itemLabel="Francais" itemValue="fr"/>

    </h:selectOneMenu>

    <h:commandButton action="#{localeSelector.select}" value="#{messages['ChangeLanguage']}"/>

Or, if you want a list of all supported locales from `faces-config.xml`, just use:

    <h:selectOneMenu value="#{localeSelector.localeString}">

        <f:selectItems value="#{localeSelector.supportedLocales}"/>

    </h:selectOneMenu>

    <h:commandButton action="#{localeSelector.select}" value="#{messages['ChangeLanguage']}"/>

When this use selects an item from the drop-down, and clicks the button, the Seam and JSF locales will be overridden for the rest of the session.

## 16.3. Labels

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

### 16.3.1. Defining labels

Seam provides a `java.util.ResourceBundle` (available to the application as a `org.jboss.seam.core.resourceBundle`). You'll need to make your internationalized labels available via this special resource bundle. By default, the resource bundle used by Seam is named `messages` and so you'll 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>

If you want to define a message just for a particular page, you can 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.jsp`.

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

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

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

### 16.3.2. Displaying labels

If you define your labels using the Seam resource bundle, you'll be able to use them without having to type `<f:loadBundle ... />` on every page. Instead, you can simply 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 super-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.

## 16.4. Timezones

There is also a session-scoped instance of `java.util.Timezone`, named `org.jboss.seam.international.timezone`, and a Seam component for changing the timezone named `org.jboss.seam.international.timezoneSelector`. By default, the timezone is the default timezone of the server. Unfortunately, the JSF specification says that all dates and times should be assumed to be UTC, and displayed as UTC, unless a timezone is explicitly specified using `<f:convertDateTime>`. This is an extremely inconvenient default behavior.

Seam overrides this behavior, and defaults all dates and times to the Seam timezone. In addition, Seam provides the `<s:convertDateTime>` tag which always performs conversions in the Seam timezone.

## 16.5. Themes

Seam applications are also very easily skinnable. The theme API is very similar to the localization API, but of course these two concerns are orthogonal, and some applications support both localization and themes.

First, configure the set of supported themes:

    <theme:theme-selector cookie-enabled="true">

        <theme:available-themes>

            <value>default</value>

            <value>accessible</value>

            <value>printable</value>

        </theme:available-themes>

    </theme:theme-selector>

Note that the first theme listed is the default theme.

Themes are defined in a properties file with the same name as the theme. For example, the `default` theme is defined as a set of entries in `default.properties`. For example, `default.properties` might define:

    css ../screen.css
    template /template.xhtml

Usually the entries in a theme resource bundle will be paths to CSS styles or images and names of facelets templates (unlike localization resource bundles which are usually text).

Now we can use these entries in our JSP or facelets pages. For example, to theme the stylesheet in a facelets page:

    <link href="#{theme.css}" rel="stylesheet" type="text/css" />

Or, when the page definition resides in a subdirectory:

    <link href="#{facesContext.externalContext.requestContextPath}#{theme.css}"

        rel="stylesheet" type="text/css" />

Most powerfully, facelets lets us theme the template used by a `<ui:composition>`:

    <ui:composition xmlns="http://www.w3.org/1999/xhtml"

        xmlns:ui="http://java.sun.com/jsf/facelets"

        xmlns:h="http://java.sun.com/jsf/html"

        xmlns:f="http://java.sun.com/jsf/core"

        template="#{theme.template}">

Just like the locale selector, there is a built-in theme selector to allow the user to freely switch themes:

    <h:selectOneMenu value="#{themeSelector.theme}">

        <f:selectItems value="#{themeSelector.themes}"/>

    </h:selectOneMenu>

    <h:commandButton action="#{themeSelector.select}" value="Select Theme"/>

## 16.6. Persisting locale and theme preferences via cookies

The locale selector, theme selector and timezone selector all support persistence of locale and theme preference to a cookie. Simply set the `cookie-enabled` property in `components.xml`:

    <theme:theme-selector cookie-enabled="true">

        <theme:available-themes>

            <value>default</value>

            <value>accessible</value>

            <value>printable</value>

        </theme:available-themes>

    </theme:theme-selector>

    <international:locale-selector cookie-enabled="true"/>

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