Dynamic Messages

With Mentawai you can easily display dynamic messages. It usually works like that: The action performs some task; adds a successful message; the browser is redirected to another action or JSP page; the success message is displayed to the user; and now if the user refreshes the page, the message disappears. An example of a dynamic message could be: "Your profile was successfully updated!".

NOTE: Some frameworks call this the flash scope.

Adding a message in the action: (flash scope)

// anywhere inside the action (that extends BaseAction)
addMessage("added_ok"); // message will come from an i18n file (see internationalization)

// OR

addMessage("The user was successfully created!");

NOTE: The flash scope works not just with a FORWARD but also with a REDIRECT. That's the beauty of it.

Showing in the JSP page:

<mtw:outMessage>
     <font color="blue"><mtw:out /></font>
</mtw:outMessage>

NOTE: The outMessage tag is a conditional tag, so the html inside the tag is only displayed if a message is present.

Adding general errors (non-flash scope):

// anywhere inside your action (that extends BaseAction)
addError("bad_username");

// OR

addError("This username is already taken!");

NOTE: It makes more sense for errors NOT to be, by default, in the flash scope so they require a FORWARD and will not work with a REDIRECT.

Displaying in the JSP page:

<mtw:outError>
     <font color="red"><mtw:out /></font>
</mtw:outError>

NOTE: The outError tag is a conditional tag, so the html inside the tag is only displayed if an error message is present.