Calling Local Services

Once Service Builder has generated your portlet project’s services, you can call them in our project’s -Portlet classes. You can call any methods in your EventLocalServiceUtil or LocationLocalServiceUtil static utility classes from EventListingPortlet and LocationListingPortlet. For example, you want the Event Listing portlet to perform create, read, update, and delete (CRUD) operations on Events and the Location Listing portlet to perform CRUD operations on Locations. To this end, you’ll create the following methods for EventListingPortlet and similar ones for LocationListingPortlet:

• addEvent
• updateEvent
• deleteEvent

Replace the contents of EventListingPortlet.java with the following code:

package com.nosester.portlet.eventlisting;

import java.util.Calendar;

import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;

import com.liferay.portal.kernel.exception.PortalException;
import com.liferay.portal.kernel.exception.SystemException;
import com.liferay.portal.kernel.log.Log;
import com.liferay.portal.kernel.log.LogFactoryUtil;
import com.liferay.portal.kernel.util.ParamUtil;
import com.liferay.portal.service.ServiceContext;
import com.liferay.portal.service.ServiceContextFactory;
import com.liferay.util.bridges.mvc.MVCPortlet;
import com.nosester.portlet.eventlisting.model.Event;
import com.nosester.portlet.eventlisting.service.EventLocalServiceUtil;

public class EventListingPortlet extends MVCPortlet {

    public void addEvent(ActionRequest request, ActionResponse response)
            throws Exception {

        _updateEvent(request);

        sendRedirect(request, response);
    }

    public void deleteEvent(ActionRequest request, ActionResponse response)
        throws Exception {

        long eventId = ParamUtil.getLong(request, "eventId");

        EventLocalServiceUtil.deleteEvent(eventId);

        sendRedirect(request, response);
    }

    public void updateEvent(ActionRequest request, ActionResponse response)
        throws Exception {

        _updateEvent(request);

        sendRedirect(request, response);
    }

    private Event _updateEvent(ActionRequest request)
        throws PortalException, SystemException {

        long eventId = ParamUtil.getLong(request, "eventId");
        String name = ParamUtil.getString(request, "name");
        String description = ParamUtil.getString(request, "description");
        long locationId = ParamUtil.getLong(request, "locationId");

        int year = ParamUtil.getInteger(request, "dateYear");
        int month = ParamUtil.getInteger(request, "dateMonth");
        int day = ParamUtil.getInteger(request, "dateDay");
        int hour = ParamUtil.getInteger(request, "dateHour");
        int minute = ParamUtil.getInteger(request, "dateMinute");
        int amPm = ParamUtil.getInteger(request, "dateAmPm");

        if (amPm == Calendar.PM) {
            hour += 12;
        }

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

        Event event = null;

        if (eventId <= 0) {
            event = EventLocalServiceUtil.addEvent(
                serviceContext.getUserId(), serviceContext.getScopeGroupId(),
                name, description, month, day, year, hour, minute, locationId,
                serviceContext);
        }
        else {
            event = EventLocalServiceUtil.getEvent(eventId);

            event = EventLocalServiceUtil.updateEvent(
                serviceContext.getUserId(), eventId, name, description, month,
                day, year, hour, minute, locationId, serviceContext);
        }
        
        return event;
    }

    private static Log _log = LogFactoryUtil.getLog(EventListingPortlet.class);
}

The Event Listing portlet’s addEvent, updateEvent, and deleteEvent methods now call the appropriate methods from EventLocalServiceUtil. Liferay’s ParamUtil getter methods such as getLong and getString return default values like 0 or "" if the specified request parameter is not available from the portlet request. When adding a new event, for example, no event ID is available so ParamUtil.getLong("request", "eventId") returns 0. The Event portlet’s addEvent method calls EventLocalServiceUtil’s addEvent method. The event ID for the new event is generated at the service layer in the addEvent method that you added to the EventLocalServiceImpl class. The EventLocalServiceUtil generated for us by Service Builder contains various CRUD methods:

• createEvent
• addEvent
• deleteEvent
• updateEvent
• fetchEvent
• getEvent

The methods listed in the figure below are all generated by Service Builder and can be called by EventListingPortlet.

Figure 4.5: Our `EventListingPortlet` class can access these methods of `EventLocalServiceUtil`, many of which are CRUD operations.

Portlet classes should have access only to the -LocalServiceUtil classes. The -LocalServiceUtil classes, in turn, call their injected -LocalServiceImpl classes. Notice in the figure above that the EventLocalServiceUtil utility class has a private instance variable called _service. The _service instance variable of type EventLocalService gets an instance of EventLocalServiceImpl at runtime via dependency injection. So all the methods of the EventLocalServiceUtil utility class internally call corresponding methods of the EventLocalServiceImpl class at runtime.

We’ve demonstrated how to call the local services generated by Service Builder in our project’s -Portlet classes. Next, let’s learn how to how to call Liferay’s local services.