Implementing Portlet Actions

Building the Web Front-End

Step 9 of 11

When users submit the form, your application stores the form data for display in the guestbook. This is where you call the back-end you generated to store the data for later retrieval in the database.

To make your portlet do anything other than re-render itself, you must implement portlet actions. An action defines some processing, usually based on user input, that the portlet must perform before it renders itself. In the case of the guestbook portlet, the action you’ll implement next saves a guestbook entry that a user typed into the form. Saved guestbook entries can be retrieved and displayed later.

Since you’re using Liferay’s MVC Portlet framework, you have an easy way to implement actions. Portlet actions are implemented in the portlet class, which is the controller. In the form you just created, you made an action URL, and you called it addEntry. To create a portlet action, you create a method in the portlet class with the same name. MVCPortlet calls that method when a user triggers its matching URL.

Creating an Add Entry Action

1. Open GuestbookPortlet.

2. Create a method with the following signature:

   public void addEntry(ActionRequest request, ActionResponse response) {
   
   }
   

3. Press [CTRL]+[SHIFT]+O to organize imports and import the required javax.portlet.ActionRequest and javax.portlet.ActionResponse classes.

You’ve now created a portlet action. It doesn’t do anything, but at least you won’t get an error now if you submit your form. Next, you should make the action save the form data.

The following method implements adding a guestbook entry using the back-end you generated with Service Builder:

public void addEntry(ActionRequest request, ActionResponse response)
            throws PortalException {

        ServiceContext serviceContext = ServiceContextFactory.getInstance(
            GuestbookEntry.class.getName(), request);

        String userName = ParamUtil.getString(request, "name");
        String email = ParamUtil.getString(request, "email");
        String message = ParamUtil.getString(request, "message");
        long guestbookId = ParamUtil.getLong(request, "guestbookId");
        long entryId = ParamUtil.getLong(request, "entryId");

    if (entryId > 0) {

        try {

            _guestbookEntryLocalService.updateGuestbookEntry(
                serviceContext.getUserId(), guestbookId, entryId, userName,
                email, message, serviceContext);

            response.setRenderParameter(
                "guestbookId", Long.toString(guestbookId));

        }
        catch (Exception e) {
            System.out.println(e);

            PortalUtil.copyRequestParameters(request, response);

            response.setRenderParameter(
                "mvcPath", "/guestbook/edit_entry.jsp");
        }

    }
    else {

        try {
            _guestbookEntryLocalService.addGuestbookEntry(
                serviceContext.getUserId(), guestbookId, userName, email,
                message, serviceContext);

            response.setRenderParameter(
                "guestbookId", Long.toString(guestbookId));

        }
        catch (Exception e) {
            System.out.println(e);

            PortalUtil.copyRequestParameters(request, response);

            response.setRenderParameter(
                "mvcPath", "/guestbook/edit_entry.jsp");
        }
    }
}

1. Replace your existing addEntry method with the above method.

2. Press [CTRL]+[SHIFT]+O to organize imports.

This addEntry method gets the name, message, and email fields that the user submits in the JSP and passes them to the service to be stored as entry data. It also gets a ServiceContext so information about the request’s current context can be retrieved, such as the ID of the current user. The if-else logic checks whether there’s an existing entryId. If there is, the update service method is called, and if not, the add service method is called. In both cases, it sets a render parameter with the Guestbook ID so the application can display the guestbook’s entries after this one has been added. This is all done in try...catch statements. Note the setting of the mvcPath render parameter to direct processing to the proper JSP based on what happens.

Creating a Delete Entry Action

Next, create an action that deletes an entry:

public void deleteEntry(ActionRequest request, ActionResponse response) throws PortalException {
        long entryId = ParamUtil.getLong(request, "entryId");
        long guestbookId = ParamUtil.getLong(request, "guestbookId");

        ServiceContext serviceContext = ServiceContextFactory.getInstance(
            GuestbookEntry.class.getName(), request);

        try {

            response.setRenderParameter(
                "guestbookId", Long.toString(guestbookId));

            _guestbookEntryLocalService.deleteGuestbookEntry(entryId);
        }

        catch (Exception e) {
            Logger.getLogger(GuestbookPortlet.class.getName()).log(
                Level.SEVERE, null, e);
        }
}

This action accepts an entryId from the request and calls the service to delete it.

But there’s something missing, isn’t there? These methods expect a guestbookId to be in the request, so the GuestbookEntry can be connected to its Guestbook. You’ll create that next, as well as a mechanism for viewing guestbook entries.