Chapter 4.  The Rating Service - Data Management

So far we have collected news headlines from CNN and saved them to the Firebase Realtime Database successfully. In this chapter, we are going to implement a service that has three main responsibilities:

• Create and save a rating logic
• Query the recorded news
• Calculate the rank and sort the collected items based on their rank

While doing these steps we will learn about how to query Firebase objects and extract the piece of data that we are looking for. But before we continue, please be advised that the purpose of the Ranking Service in our project is to help us to find which headline is worth investigation.

So basically it is just a helper and at the end of the day, you are the one who will decide which headline you should chose. In other words, in this chapter we will use the Rating service just to get some insight and find a direction. However, in the chapters to come - especially when we set everything in auto pilot mode - we will...