In this tutorial, you’ll learn about the differences between local and remote services, and when you should invoke local services rather than their remote service counterparts.

Once Service Builder has generated your module project’s services, you can call them from anywhere in your application. When invoking a local service, you should call one of the service methods of a *LocalService class. You should never call the service methods of an *Impl class directly. Local services in your project are generated automatically when using Service Builder. To do this, set the local-service attribute to true for an entity in the service.xml file. Service Builder generates methods that call existing services, but you can create new methods in the *LocalServiceImpl class that can be generated into new exposed methods in your module’s services (*LocalService, *LocalServiceUtil, etc.).

Many of Liferay’s module applications use their generated remote services for important calls in their controller layer, for example, because they offer conveniences like configured permissions checking. Remote services perform a permission check and then invoke the corresponding local service. However, there are many services you’d like to expose only to your local project, and do not want other applications to have access to.

In the Bookmarks application, for example, the BookmarksEntryLocalService interface provides the openEntry method, which opens a bookmark for viewing. The remote service interface BookmarksEntryService, however, does not provide this method. Why could this be?

There are many services that you don’t want to expose to other applications in Liferay. In the example mentioned above, Bookmarks are configured to only open locally, meaning that other apps do not have access to open and view a bookmark entry. This should only be done by the Bookmarks application. Therefore, in certain cases, you’ll need to invoke local services instead of remote services. For more information on invoking remote services, see the Invoking Remote Services tutorial.

To see how you could call a local service from a portlet action class, you’ll examine the EditOrganizationMVCActionCommand class. Notice that this class has a private instance variable called _dlAppLocalService. The _dlAppLocalService instance variable of type DLAppLocalService gets an instance of DLAppLocalService at runtime via dependency injection. The instance variable is set like this:

@Reference(unbind = "-")
protected void setDLAppLocalService(DLAppLocalService dlAppLocalService) {
    _dlAppLocalService = dlAppLocalService;
}

This tutorial demonstrated how you can call the local services generated by Service Builder in your project. To learn how to call Liferay services, see the Service Security Layers and Finding and Invoking Liferay Services tutorials.

Related Topics

Creating Local Services

Creating Remote Services

Invoking Remote Services

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