Gimme a CLI

Gimme a CLI is a Java library for creating quick and easy command line interfaces (CLIs) using JCommander and Spring's IoC Container.

• JCommander is great for creating command-style CLI argument parsers. Examples of command-style CLIs include git and the AWS CLI.
• Spring's IoC Container provides dependency injection which helps reduce boiler plate and makes it easier to write testable code.
• Gimme a Cli eliminates the tedious setup you would otherwise have to do.

Getting Started

Example starter project can simply be cloned and modified.

Usage

1. Define one or more commands for your CLI by implementing the Command interface.

   import com.nike.gimme.a.cli.Command;
   
   public class HelloWorld implements Command {
   
       @Override
       public void execute() {
           System.out.println("Hello World!");
       }
   }

   Commands are automatically instantiated as Spring beans (e.g. dependencies can be supplied via constructor injection, etc).

2. Optionally use JCommander annotations to define command arguments and options.

   import com.beust.jcommander.Parameter;
   import com.beust.jcommander.Parameters;
   import com.nike.gimme.a.cli.Command;
   
   @Parameters(commandNames = "hello-world",
               commandDescription = "Prints \"Hello <name>\" to the terminal")
   public class HelloWorld implements Command {
   
       @Parameter(names = {"--name"}, required = true)
       private String name;
       
       @Override
       public void execute() {
           System.out.println("Hello " + name);
       }
   }

3. Define a main class and run the GimmeACli program.

   import com.nike.gimme.a.cli.Config;
   import com.nike.gimme.a.cli.GimmeACli;
   
   public class Main {
   
       public static void main(String[] args) {
           new GimmeACli(
                   Config.builder()
                           .withCliName("my-cli-name")
                           .withPackagesToScan("com.nike")
                           .build()
           ).run(args);
       }
   }

   Spring setup is done for you using classpath scanning.

4. Configure SLF4J logging, e.g.,

   1. Include logback as a dependency.

      dependencies {
          implementation "ch.qos.logback:logback-classic:1.1.11"
      }

   2. Provide a logback.xml.

All of these steps have been done for you in the example starter project which can simply be cloned and modified to fit your needs..

Additional Features

• Global --help option gives nicely formatted output.

References

• JCommander - a library for CLI argument parsing.
• Spring's IoC - a library for easy dependency injection.
• gimme-a-cli-starter-project - An example starter project that can simply be cloned and modified.