Arguments

Arguments in the CommandAPI are registered by using an Argument[] or List<Argument> object. There are two things you need to keep in mind when creating arguments:

• The order which they will be used
• The type of each argument

By definition of a List, the order of the elements inserted into it are preserved, meaning the order you add arguments to the List will be the resulting order of which arguments are presented to the user when they run that command.

Adding arguments for registration is simple:

// Create a List
List<Argument> arguments = new ArrayList<>();

// Add an argument with the node "target", which is a PlayerArgument
arguments.add(new PlayerArgument("target"));

The String value is the node that is registered into Minecraft's internal command graph. This is name is also used as a prompt that is shown to a player when they are entering the command.

The CommandAPI is very flexible when it comes to registering arguments, and lets you use a number of different methods to suit your preference:

new CommandAPICommand("mycommand")
    .withArguments(new StringArgument("arg0"))
    .withArguments(new StringArgument("arg1"))
    .withArguments(new StringArgument("arg2"))
    // And so on

new CommandAPICommand("mycommand")
    .withArguments(new StringArgument("arg0"), new StringArgument("arg1"), new StringArgument("arg2"))
    // And so on

List<Argument<?>> arguments = new ArrayList<>();
arguments.add(new StringArgument("arg0"));
arguments.add(new StringArgument("arg1"));
arguments.add(new StringArgument("arg2"));

new CommandAPICommand("mycommand")
    .withArguments(arguments)
    // And so on

Argument Casting

To access arguments, they have to be casted to the type that the argument represents. The order of the arguments in the args[] is the same as the order in which the arguments were declared.

List<Argument<?>> arguments = new ArrayList<>();
arguments.add(new StringArgument("arg0"));
arguments.add(new PotionEffectArgument("arg1"));
arguments.add(new LocationArgument("arg2"));

new CommandAPICommand("cmd")
    .withArguments(arguments)
    .executes((sender, args) -> {
        String stringArg = (String) args[0];
        PotionEffectType potionArg = (PotionEffectType) args[1];
        Location locationArg = (Location) args[2];
    })
    .register();

The type to cast each argument (declared in the dev.jorel.commandapi.arguments package) is listed below:

Optional/Different Arguments

Sometimes, you want to register a command that has a different effect whether arguments are included or not. For example, take the /kill command. If you run /kill on its own, it will kill the command sender. If however you run /kill <target>, it will kill the target. In other words, we have the following command command syntax:

/kill          - Kills yourself
/kill <target> - Kills a target player

As shown by the command syntax, we need to register two commands.

/kill          - Kills yourself
/kill <target> - Kills a target player

new CommandAPICommand("kill")
    .executesPlayer((player, args) -> {
        player.setHealth(0);
    })
    .register();

// Register our second /kill <target> command
new CommandAPICommand("kill")
    .withArguments(new PlayerArgument("target"))
    .executesPlayer((player, args) -> {
        ((Player) args[0]).setHealth(0);
    })
    .register();