CommandAPICommand withSubcommand(CommandAPICommand subcommand);

Example - Permission system with subcommands

Say we wanted to write a permission management system. To do this, we'll use the following command structure:

/perm group add <permission> <groupName>
/perm group remove <permission> <groupName>
/perm user add <permission> <userName>
/perm user remove <permission> <userName>

Let's start with the simplest example - the /perm group ... command. We have one command which is basically the following:

add <permission> <groupName>

We can implement this by creating a CommandAPICommand with the command name add:

CommandAPICommand groupAdd = new CommandAPICommand("add")
	.withArguments(new StringArgument("permission"))
	.withArguments(new StringArgument("groupName"))
	.executes((sender, args) -> {
	    //perm group add code
	});

Similarly, we have another part remove <permission> <groupName>. We can declare this similar to our add command. Once we've done that, we can now join everything up together. Here, we create a command group which adds the two other subcommands:

CommandAPICommand groupRemove = new CommandAPICommand("remove")
	.withArguments(new StringArgument("permission"))
	.withArguments(new StringArgument("groupName"))
	.executes((sender, args) -> {
	    //perm group remove code
	});

CommandAPICommand group = new CommandAPICommand("group")
	.withSubcommand(groupAdd)
	.withSubcommand(groupRemove);

Finally, we can link everything up together to the perm command and register the whole thing together:

new CommandAPICommand("perm")
    .withSubcommand(group)
    .register();

---

Another, more intuitive method, is to shove everything in one go without creating lots of variables all over the place:

new CommandAPICommand("perm")
    .withSubcommand(new CommandAPICommand("group")
        .withSubcommand(new CommandAPICommand("add")
            .withArguments(new StringArgument("permission"))
            .withArguments(new StringArgument("groupName"))
            .executes((sender, args) -> {
                //perm group add code
            })
        )
        .withSubcommand(new CommandAPICommand("remove")
            .withArguments(new StringArgument("permission"))
            .withArguments(new StringArgument("groupName"))
            .executes((sender, args) -> {
                //perm group remove code
            })
        )
    )
    .withSubcommand(new CommandAPICommand("user")
        .withSubcommand(new CommandAPICommand("add")
            .withArguments(new StringArgument("permission"))
            .withArguments(new StringArgument("userName"))
            .executes((sender, args) -> {
                //perm user add code
            })
        )
        .withSubcommand(new CommandAPICommand("remove")
            .withArguments(new StringArgument("permission"))
            .withArguments(new StringArgument("userName"))
            .executes((sender, args) -> {
                //perm user remove code
            })
        )
    )
    .register();