Using TreeMap instead of LinkedHashMap, to sort subcommands alphabeti…

[frontfact]

Using TreeMap instead of LinkedHashMap, to sort subcommands alphabetically in usage message.

Tell me if that breaks something.

Below is a snippet to toy with the expected behaviour (with/without ordering).

`
public class TestApplication {

@Command(name = "alpha")
public static class Alpha implements Callable<Integer> {
	@Override
	public Integer call() throws Exception {
		return 0;
	}
}

@Command(name = "bravo")
public static class Bravo implements Callable<Integer> {
	@Override
	public Integer call() throws Exception {
		return 0;
	}
}

@Command(name = "charlie")
public static class Charlie implements Callable<Integer> {
	@Override
	public Integer call() throws Exception {
		return 0;
	}
}

@Command(name = "$",
		subcommands = {
			Charlie.class,
			Bravo.class,
			Alpha.class,
			HelpCommand.class
		})
public static class RootCommand implements Callable<Integer> {
	@Override
	public Integer call() throws Exception {
		throw new UnsupportedOperationException();
	}
}

public static void main(String[] args) {
	CommandLine rootCommand = new CommandLine(new RootCommand());
	rootCommand.usage(System.out);
}

}
`

[remkop]

Hi @frontfact, thank you for the PR!

To be honest, I’m not sure that this is a good change:
With the current implementation (using LinkedHashMap), applications have control over the order in which subcommands are listed. Applications that want to list subcommands alphabetically can simply list them in that order. They also have the option to list subcommands in a different order.

Your proposal would limit applications to only alphabetical order, which doesn’t seem to be a good thing. Or am I missing something?

[frontfact]

Hi

Applications that want to list subcommands alphabetically can simply list them in that order

Unfortunately, this is not possible in my case: I have 2 different applications that share common commands. I cannot list commands in the alphabetical order.

They also have the option to list subcommands in a different order

I did not see that, can you tell me how to do that ? Or point me to the documentation section explaining how to achieve alphabetical ordering of subcommands.

Thank you very much

[remkop]

I thought subcommands are listed in the order that they are declared. So you can control the ordering, no?

[frontfact]

Yes, I see.
To be clear, my project has a shared library that initializes common commands first, then each tool initializes additionnal commands or sub-commands. This is why I can't order commands alphabetically in source code, and wanted them to be sorted at runtime.

Thank you for your time, have a nice day!

[remkop]

Ok, I see now.
We can find a solution for your use case. Give me a few minutes.

[remkop]

I believe that we can meet your requirements with a custom IHelpSectionRenderer.

This ticket has an (fairly complex) example.

A custom IHelpSectionRenderer that simply sorts the commands by name should be easier than that example. I’ll take a closer look when I get back behind my computer.

[remkop]

@frontfact, I found an easier solution: you can subclass Help and override the Help.subcommands() method to return a sorted map.

Here is a full example:

import picocli.CommandLine;
import picocli.CommandLine.Command;
import picocli.CommandLine.Help;
import picocli.CommandLine.HelpCommand;
import picocli.CommandLine.IHelpFactory;
import picocli.CommandLine.Model.CommandSpec;
import picocli.CommandLine.Spec;

import java.util.Map;
import java.util.TreeMap;

/**
 * This class has subcommands that are not declared alphabetically.
 * We want the help for this class to show the subcommands alphabetically.
 */
@Command(name = "alphabetic",
        description = "a command that shows subcommands sorted alphabetically",
        subcommands = {Charlie.class, Bravo.class, Alpha.class, HelpCommand.class})
public class AlphabeticSubcommands implements Runnable {

    @Spec CommandSpec spec;

    @Override
    public void run() {
        spec.commandLine().usage(System.out);
    }

    public static void main(String[] args) {
        CommandLine commandLine = new CommandLine(new AlphabeticSubcommands());
        commandLine.setHelpFactory(new IHelpFactory() {
            @Override
            public Help create(CommandSpec commandSpec, Help.ColorScheme colorScheme) {
                return new Help(commandSpec, colorScheme) {
                    /**
                     * Returns a sorted map of the subcommands.
                     */
                    @Override
                    protected Map<String, Help> subcommands() {
                        return new TreeMap<>(super.subcommands());
                    }
                };
            }
        });
        commandLine.execute(args);
    }
}

@Command(name = "charlie", description = "my name starts with C")
class Charlie implements Runnable {
    public void run() {}
}

@Command(name = "bravo", description = "my name starts with B")
class Bravo implements Runnable {
    public void run() {}
}

@Command(name = "alpha", description = "my name starts with A")
class Alpha implements Runnable {
    public void run() {}
}

Output:

 Usage: alphabetic [COMMAND]
a command that shows subcommands sorted alphabetically
Commands:
  alpha    my name starts with A
  bravo    my name starts with B
  charlie  my name starts with C
  help     Displays help information about the specified command

Does this meet your requirements?

[frontfact]

That works perfectly, thank you very much !

[remkop]

Great, glad to hear that!
Please star the project on GitHub if you like it! 😉