Argument Parser (arg)

The Argument Parser (arg) framework provides a clean and efficient way of handling command line arguments.

Features

• Mimics the Docker CLI resource -> action on resource style
• Command Modifiers
  • Optionally take in a value of a generic type (ex: Integer, String, Boolean)
  • Enforce that type with builtin exception handlers
  • Automatically wired in to your command's execute() method, allowing you to modify the output of that command depending on the modifiers specified
• Command Containers (Subcommands)
  • Navigational, container like objects that don't provide any business logic
  • Designed to represent a particular resource, like images in Docker's case
• Exception handlers
  • Built in exception handlers to deal with scenarios such as:
    • Command/Command Container/Command Modifier not found
    • Command/Command Container not specified
    • Incorrect command modifier input data type
• Built in support for colored logging (Windows, macOS and Linux)
• Accept required input on a Command level
• Automatic help text generation and printing
• Exit code propagation
  • Define your exit code in an exception handler

Usage

/**
 * Main.java
 */

public class Main() {
    public static void main(String[] args) {
        EspressoArgumentParser argumentParser = new EspressoArgumentParser("Docker", "Containers, yo!");

        // build our command
        Command command = new Command("ps", "List all images on this system") {
            @Override
            public void execute(List<CommandModifier> commandModifiers) {
                System.out.println("Do your business logic here!");
            }
        };

        // wrap your commands in a command container
        CommandContainer commandContainer = new CommandContainer("images", "Show all top level images");
        commandContainer.addCommand(command);
        
        // add that container to your parser
        argumentParser.addCommandContainer(commandContainer);
        
        // enter the parser
        argumentParser.parse(args);
    }
}

...now run your .jar file with the images ps arguments, you should see the text Do your business logic here! print to the console!

Reason

I strongly disliked how other libraries like Apache Commons CLI work, especially since they seem to enforce a GNU style on the developer. EAP enforces a resource-style (similar to Docker CLI) structure, with support for modifiers on any particular command.