Book Image

Java 9 Programming Blueprints

By : Lee
Book Image

Java 9 Programming Blueprints

By: Lee

Overview of this book

Java is a powerful language that has applications in a wide variety of fields. From playing games on your computer to performing banking transactions, Java is at the heart of everything. The book starts by unveiling the new features of Java 9 and quickly walks you through the building blocks that form the basis of writing applications. There are 10 comprehensive projects in the book that will showcase the various features of Java 9. You will learn to build an email filter that separates spam messages from all your inboxes, a social media aggregator app that will help you efficiently track various feeds, and a microservice for a client/server note application, to name a few. The book covers various libraries and frameworks in these projects, and also introduces a few more frameworks that complement and extend the Java SDK. Through the course of building applications, this book will not only help you get to grips with the various features of Java 9, but will also teach you how to design and prototype professional-grade applications with performance and security considerations.
Table of Contents (13 chapters)
9
Taking Notes with Monumentum

Building your first function

The heart of Functions as a Service is, of course, the function. In Amazon Web Services, these are deployed using the service AWS Lambda. That's not the only AWS feature we'll use, as we've already mentioned. Once we have a function, we need a way to execute it. This is done via one or more triggers, and the function itself has tasks it needs to perform, so we'll demonstrate more service usage via API calls when we finally write the function.

It might be helpful at this point, given that our application is structured significantly differently than anything else we've looked at, to look at a system diagram:

Here's the rough flow:

  • A message is published to a topic in the Simple Notification System
  • Once the permissions of the caller have been verified, the message is delivered
  • Upon message delivery, a trigger is fired,...