Handling element routes

As we saw earlier, tags can receive element routes as values. Let's see how to handle these when making a custom tag.

The route parser

When a tag receives a route as a value, it may be forwarded to the RouteParser class, which is responsible for parsing the route and returning the element it points to.

var command = ArgumentParser.from(Program.class);

// element is the arugment `my-arg` of the command given
var element = RouteParser.parse(command, "args.my-arg");

And now nothing prevents us from using this in our tag parse method:

	public class MyTag extends Tag {
		@Override
		protected String parse(NamedWithDescription user, String value) {
			return RouteParser.parse(user, value).getName();
		}
	}

Example

Here is a more complete example of a tag that uses the route parser to return information about some of the elements.

public class MyTag extends Tag {
    @Override
    protected String parse(NamedWithDescription user, String value) {
        return switch (RouteParser.parse(user, value)) {
            case Argument<?, ?> arg -> "I'm an argument with a default value of " + arg.getDefaultValue() + ".";
            case Command cmd -> "I'm a command with " + cmd.getGroups().size()
                + " groups and " + cmd.getArguments().size() + " arguments.";
            case Group grp -> "I'm a" + (grp.isRestricted() ? " restricted" : "n unrestricted") + " group.";
            default -> "I am something else.";
        };
    }
}

Last modified: 15 June 2025