Adding Failure and Success Messages

Displaying Messages and Errors

Step 2 of 3

To display feedback to users properly, you must edit your portlet classes to use Liferay DXP’s SessionMessages and SessionErrors classes. These classes collect messages that the view layer shows to the user through a tag.

You’ll add these messages to code that runs when the user triggers a system function that can succeed or fail, such as creating, editing, or deleting a Guestbook or Guestbook entry. This happens in action methods. You must update these methods to handle failure and success states in GuestbookPortlet.java and GuestbookAdminPortlet.java. Start by updating addEntry and deleteEntry in GuestbookPortlet.java:

1. Find the addEntry method in GuestbookPortlet.java. In the first try...catch block’s try section, and add the success message just before the closing }:

   SessionMessages.add(request, "entryAdded");
   

   This uses Liferay’s SessionMessages API to add a success message whenever a Guestbook is successfully added. It looks up the message you placed in the Language.properties file and inserts the message for the key entry-added (it automatically converts the key from camel case).

2. Below that, in the catch block, find the following code:

   System.out.println(e);
   

3. Beneath it, paste this line:

   SessionErrors.add(request, e.getClass().getName());
   

   Now you not only log the message to the console, you also use the SessionErrors object to show the message to the user.

Next, do the same for the deleteEntry method:

1. After the logic to delete the entry, add a success message:

   SessionMessages.add(request, "entryDeleted");
   

2. Find the Logger... block of code in the deleteEntry method and after it, paste this line:

   SessionErrors.add(request, e.getClass().getName());
   

3. Hit [CTRL]+[SHIFT]+O to import com.liferay.portal.kernel.servlet.SessionErrors and com.liferay.portal.kernel.servlet.SessionMessages. Save the file.

Well done! You’ve added the messages to GuestbookPortlet. Now you must update GuestbookAdminPortlet.java:

1. Open GuestbookAdminPortlet.java and look for the same cues.

2. Add the appropriate success messages to the try section of the try...catch in addGuestbook, updateGuestbook, and deleteGuestbook, respectively:

   SessionMessages.add(request, "guestbookAdded");
   
   SessionMessages.add(request, "guestbookUpdated");
   
   SessionMessages.add(request, "guestbookDeleted");
   

3. In the catch section of those same methods, find Logger.getlogger... and paste the SessionErrors block beneath it:

   SessionErrors.add(request, pe.getClass().getName());
   

4. Hit [CTRL]+[SHIFT]+O to import SessionErrors and SessionMessages. Save the file.

Great! The controller now makes relevant and detailed feedback available. Now all you need to do is publish this feedback in the view layer.