Book Image

Java 9 Programming Blueprints

By : Jason Lee
Book Image

Java 9 Programming Blueprints

By: Jason 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 (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
9
Taking Notes with Monumentum

Building the command-line interface


In the last chapter, we built a command-line tool using the Crest library from Tomitribe, and it worked out pretty well, so we will return to the library in building this command line as well.

To enable Crest in our project, we must do two things. First, we have to configure our POM file as follows:

    <dependency> 
      <groupId>org.tomitribe</groupId> 
      <artifactId>tomitribe-crest</artifactId> 
      <version>0.8</version> 
    </dependency> 

We must also update our module definition in src/main/java/module-info.java as follows:

    module datecalc.cli { 
      requires datecalc.lib; 
      requires tomitribe.crest; 
      requires tomitribe.crest.api; 
     
      exports com.steeplesoft.datecalc.cli; 
    } 

We can now define our CLI class like this:

    public class DateCalc { 
      @Command 
      public void dateCalc(String... args) { 
        final String expression = String.join(" ", args); 
 ...