Recipe12.5.Creating Localized Messages from an Action

Recipe 12.5. Creating Localized Messages from an Action

Problem

You need to create a localized message from within an Action.

Solution

MessageResources resources = getResources(request); Locale locale = getLocale(request); String msg1 = resources.getMessage(locale, "message.success")); String msg2 = resources.getMessage(locale, "msg.hello", "Bill"));

Discussion

Application messages for information and errors are typically created using the ActionMessage and ActionError classes. These messages are saved in the request using the saveMessages( ) and saveErrors( ) methods.

The ActionError class has been deprecated in Struts 1.2. The ActionMessage class should be used instead.

But you can retrieve localized text messages in the Action itself. You may need the message in the Action because you are logging this information or you need to pass the message to some other service. The Solution shows how you can get a localized message in an Action. The MessageResources and current Locale are retrieved using the getresources( ) and getLocale() methods of the base Action class. MessageResources provides a number of variations of the getMessage( ) method. There are three basic pieces of information you can pass:

locale: The requested message Locale or null for the system default Locale
key: The message key to look up
args: An array of replacement parameters for placeholders in the message

You can retrieve messages from an alternate MessageResources set. Suppose you've declared your alternate set in the struts-config.xml file:

<message-resources key="alt"     parameter="AlternateResources"> </message-resources

The getresources( ) method takes an optional parameter specifying the name of the MessageResources bundle, identified by the key attribute of the message-resources element:

MessageResources resources = getResources(request, "alt");

If you only have access to the servlet request, you can create messages but you have to get the Locale and MessageResources through different means. To get the Locale, use the RequestUtils class in the org.apache.struts.util package:

Locale locale = RequestUtils.getUserLocale(request, null);

The default set of MessageResources can be retrieved using:

MessageResources resources =      (MessageResources) request.getAttribute(Globals.MESSAGES_KEY));

You can use one of the MessageResources.getMessage() methods to retrieve the message.

You can retrieve an alternate set of MessageResources, but the code is more involved because modules are taken into account. Take a look at the source for the Action class if you're interested.

Recipe12.5.Creating Localized Messages from an Action