Updating Your Service Layer

Writing the Guestbook Admin App

Step 3 of 6

Earlier, you wrote an addGuestbook service method in GuestbookLocalServiceImpl and only used it to add a default guestbook. To have full functionality over guestbooks, you must also add methods for updating and deleting guestbooks, as well as for returning the number of guestbooks in a Site.

Adding Guestbook Service Methods

Remember that when working with Service Builder, you define your service in the *Impl classes. After you add, remove, or change the signature of a method in an *Impl class, you must run Service Builder. Service Builder updates the affected interfaces and any other generated code.

Follow these steps to add the required guestbook service methods:

  1. Go to the guestbook-service project and open GuestbookLocalServiceImpl.java in the com.liferay.docs.guestbook.service.impl package. Add the following method for updating a guestbook:

    public Guestbook updateGuestbook(long userId, long guestbookId,
        String name, ServiceContext serviceContext) throws PortalException,
                    SystemException {
            Date now = new Date();
            Guestbook guestbook = getGuestbook(guestbookId);
            User user = userLocalService.getUser(userId);
            return guestbook;

    The updateGuestbook method retrieves the Guestbook by its ID, replaces its data with what the user entered, and then calls the persistence layer to save it back to the database.

  2. Next, add the following method for deleting a guestbook:

    public Guestbook deleteGuestbook(long guestbookId,
                    ServiceContext serviceContext) throws PortalException,
                    SystemException {
            Guestbook guestbook = getGuestbook(guestbookId);
            List<GuestbookEntry> entries = _guestbookEntryLocalService.getGuestbookEntries(
                            serviceContext.getScopeGroupId(), guestbookId);
            for (GuestbookEntry entry : entries) {
            guestbook = deleteGuestbook(guestbook);
            return guestbook;

    It’s important to consider what should happen if you delete a guestbook that has existing entries. If you only deleted the guestbook, the guestbook’s orphaned entries would still exist in the database. Your deleteGuestbook service method makes a service call to delete a guestbook’s entries before deleting that guestbook. This way, guestbook entries are never orphaned.

  3. Add a reference to the GuestbookEntry local service, so it can be injected and used by the deleteGuestbook method:

    private GuestbookEntryLocalService _guestbookEntryLocalService;

    By convention, Liferay adds these to the bottom of the class.

  4. Use [CTRL]+[SHIFT]+O to update your imports, choosing com.liferay.portal.kernel.exception.SystemException, and then save GuestbookLocalServiceImpl.java.

  5. In the Gradle Tasks pane on the right side in Liferay Dev Studio DXP, run Service Builder by opening the guestbook-service module and double-clicking buildService.

Now that you’ve finished updating the service layer, it’s time to work on the Guestbook Admin portlet itself.

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