Using a Tracking Mechanism

An administrator has successfully configured and saved your custom metric to his or her report. Now what? Your metric needs to fulfill its purpose, which is to track the view event type for the defined newsletter. To do this, you must define a tracking mechanism. For your newsletter, you’ll use a transparent image as the tracking mechanism, which would have the View tracking event capability. Whenever the image is viewed, the newsletter metric computes and stores the information.

For the newsletter metric, you’ll use a tracking mechanism provided by the Audience Targeting app.

1. Set the analytics processor that the Content Targeting API provides for tracking events. Add the following method and private field:

   @Reference
   protected void setAnalyticsProcessor(AnalyticsProcessor analyticsProcessor) {
       _analyticsProcessor = analyticsProcessor;
   }
   
   private AnalyticsProcessor _analyticsProcessor;
   

   The analytics processor contains a servlet to track analytics from Liferay pages (views, clicks, etc.) and an API to leverage this tracking mechanism. In the setAnalyticsProcesoor(...) method, you’re obtaining a reference of the current analytics processor to build the URL used to generate a transparent image. All you have to do is insert the generated URL into your newsletter’s HTML, and the transparent image tracks who reads it. Everything is processed by the default Audience Targeting Analytics system automatically.

   Now that you’ve obtained a reference of the analytics processor, you need to add logic for generating the appropriate tracking URL.

2. Replace the populateContext method with the updated method:

   @Override
   protected void populateContext(
       TrackingActionInstance trackingActionInstance,
       Map<String, Object> context, Map<String, String> values) {
   
       String alias = StringPool.BLANK;
       String elementId = StringPool.BLANK;
       String eventType = StringPool.BLANK;
       String trackImageHTML = StringPool.BLANK;
   
       if (!values.isEmpty()) {
           alias = values.get("alias");
           elementId = values.get("elementId");
           eventType = values.get("eventType");
       }
       else if (trackingActionInstance != null) {
           alias = trackingActionInstance.getAlias();
           elementId = trackingActionInstance.getElementId();
           eventType = trackingActionInstance.getEventType();
   
           String trackImageURL = _analyticsProcessor.getTrackingURL(
               trackingActionInstance.getCompanyId(), 0, 0, "", 0,
               Campaign.class.getName(),
               new long[] {trackingActionInstance.getCampaignId()},
               trackingActionInstance.getElementId(), "view", "");
   
           trackImageHTML = "<img alt=\"\" src=\"" + trackImageURL + "\" />";
       }
   
       context.put("alias", alias);
       context.put("elementId", elementId);
       context.put("eventType", eventType);
       context.put("eventTypes", getEventTypes());
       context.put("trackImageHTML", trackImageHTML);
   }
   

   This updated method creates a new variable named trackImageHTML, retrieves a tracking URL using the analytics processor, and then populates the trackImageHTML context variable. When creating a new metric, the transparent image’s URL field is not present in the metric’s form. When the metric is initially saved, however, the URL is generated using the analytics processor and is available for copying.

Excellent! You’ve obtained the analytics processor and can create the transparent image tracking mechanism. The newsletter metric’s behavior is defined and complete. The last thing you need to do is create a JSP template.