Creating a Metric

Now that all of your criteria has been defined, you can get started developing the actual metric:

Note: To view the Javadoc for the Content Targeting classes mentioned in this article, download the Javadoc JAR.

1. Create a module project for deploying a metric. A Blade CLI content-targeting-tracking-action template is available to help you get started quickly. It sets the default configuration for you, and it contains boilerplate code so you can skip the file creation steps and get started right away.

2. Make sure your module specifies the dependencies necessary for an Audience Targeting metric. For example, you should specify the Content Targeting API and necessary Liferay packages. For example, this is the example build.gradle file used from a Gradle based metric:

   dependencies {
       compileOnly group: "com.liferay.content-targeting", name: "com.liferay.content.targeting.analytics.api", version: "5.0.0"
       compileOnly group: "com.liferay.content-targeting", name: "com.liferay.content.targeting.anonymous.users.api", version: "3.0.0"
       compileOnly group: "com.liferay.content-targeting", name: "com.liferay.content.targeting.api", version: "5.0.0"
       compileOnly group: "com.liferay.portal", name: "com.liferay.portal.kernel", version: "3.6.2"
       compileOnly group: "com.liferay.portal", name: "com.liferay.util.taglib", version: "2.0.0"
       compileOnly group: "javax.portlet", name: "portlet-api", version: "3.0.0"
       compileOnly group: "javax.servlet", name: "javax.servlet-api", version: "3.0.1"
       compileOnly group: "org.osgi", name: "org.osgi.service.component.annotations", version: "1.3.0"
   }
   

   You can learn more about exposing the Content Targeting API in the Accessing the Content Targeting API tutorial. Once you’ve created your module and specified its dependencies, you’ll need to define your metric’s behavior. How your metric behaves is controlled by a Java class file that you create.

3. Create a unique package name in the module’s src directory, and create a new Java class in that package. To follow naming conventions, your class name should begin with the metric’s name you’re creating and end with TrackingAction (e.g., NewsletterTrackingAction.java). Your Java class should implement the com.liferay.content.targeting.api.model.TrackingAction interface.

   You must implement the TrackingAction interface, but there are TrackingAction extension classes that provide helpful utilities that you can extend. For example, your metric can extend the BaseJSPTrackingAction class to support generating your metric’s UI using JSPs. This tutorial demonstrates implementing the UI using a JSP and assumes the TrackingAction interface is implemented by extending the BaseJSPTrackingAction class. For more information on choosing a UI for your metric, see the Selecting a UI Technology section.

4. Directly above the class’s declaration, insert the following annotation:

   @Component(immediate = true, service = TrackingAction.class)
   

   This declares the Component’s implementation class and configures it to start immediately once deployed to Liferay DXP.

Now that your Java class is set up, you must define how your metric works by implementing the TrackingAction interface’s methods. You’ll begin implementing these methods next.