Book Image

Java 9: Building Robust Modular Applications

By : Dr. Edward Lavieri, Peter Verhas, Jason Lee
Book Image

Java 9: Building Robust Modular Applications

By: Dr. Edward Lavieri, Peter Verhas, Jason Lee

Overview of this book

Java 9 and its new features add to the richness of the language; Java is one of the languages most used by developers to build robust software applications. Java 9 comes with a special emphasis on modularity with its integration with Jigsaw. This course is your one-stop guide to mastering the language. You'll be provided with an overview and explanation of the new features introduced in Java 9 and the importance of the new APIs and enhancements. Some new features of Java 9 are ground-breaking; if you are an experienced programmer, you will be able to make your enterprise applications leaner by learning these new features. You'll be provided with practical guidance in applying your newly acquired knowledge of Java 9 and further information on future developments of the Java platform. This course will improve your productivity, making your applications faster. Next, you'll go on to implement everything you've learned by building 10 cool projects. 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 just a few. By the end of this course, you will be well acquainted with Java 9 features and able to build your own applications and projects. This Learning Path contains the best content from the following two recently published Packt products: • Mastering Java 9 • Java 9 Programming Blueprints
Table of Contents (33 chapters)
Title Page - Courses
Packt Upsell - Courses
Preface
25
Taking Notes with Monumentum
Bibliography
Index

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); 
 ...