Arguments

Arguments in the CommandAPI are registered by using a LinkedHashMap<String, 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 LinkedHashMap, the order of the elements inserted into it are preserved, meaning the order you add arguments to the LinkedHashMap 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 LinkedHashMap
LinkedHashMap<String, Argument> arguments = new LinkedHashMap<>();

//Add an argument called "target", which is a PlayerArgument
arguments.put("target", new PlayerArgument());

The String value is the prompt that is shown to a player when they are entering the command.

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.

LinkedHashMap<String, ArgumentType> arguments = new LinkedHashMap<>();
arguments.put("arg0", new StringArgument());
arguments.put("arg1", new PotionEffectArgument());
arguments.put("arg2", new LocationArgument());

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 structure:

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

As shown by the command structure, 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();

// Declare our arguments
LinkedHashMap<String, Argument> arguments = new LinkedHashMap<>();
arguments.put("target", new PlayerArgument());

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