This is a little framework to help the creation of a command line shell console in Java.

What should be configurable:

• Where to find commands, and how to run them
  • from beans in Spring application context
  • from jars in plugins directory
  • from groovy or jython files
  • embedded in my source code
• How to parse commands and options
  • JCommander (http://jcommander.org/)
  • Commons CLI (https://commons.apache.org/proper/commons-cli/)
  • custom made options parser
• How to display command help
  • custom formatting
• Initialization and destruction
  • Hooks for initialization and destruction in the shell life cycle
• Customizable
  • startup message
  • prompt
  • error messages
  • tab completion

What josh must provide:

• A framework to glue all the components together
• Standard implementation of common components
• Command line editing and history

Don't depend on a lot of external libraries

• The only required dependency is slf4j-api
• jline2 and jcommander are optional dependencies

A simple example of a basic shell with the built in commands, and no customization.

package josh.example;

import josh.command.builtin.BuiltInCommandProvider;
import josh.shell.BasicConsoleProvider;
import josh.shell.LineParserImpl;
import josh.shell.Shell;

public class MinimalShell {

    public static void main(String[] args) {
        Shell shell = new Shell();
        shell.setLineParser(new LineParserImpl());
        shell.setCommandProvider(new BuiltInCommandProvider());
        shell.setConsoleProvider(new BasicConsoleProvider());
        System.exit(shell.runInteractive().getExitCode());
    }

}

To add you own commands you must implement the interface CommandProvider. The josh-example module has some examples that could be used as a starting point.

To use advanced line editing capabilities, instead of BasicConsoleProvider you should use JLineConsoleProvider that is already included in josh.

        JLine2ConsoleProvider provider = new JLine2ConsoleProvider();
        provider.setHistory(System.getProperty("user.home") + "/.josh/", "josh_history", 800);
        provider.setPromptColor(Ansi.Color.CYAN);
        provider.setErrorColor(Ansi.Color.RED);
        provider.addCompleter(new CommandCompleter(shell.getLineParser(), shell.getCommandProvider()));
        provider.setPrompt("> ");

        shell.setConsoleProvider(provider);

This framework was tested on Linux. If you run it on Windows and find a bug (or not!) let us know.