Normal command executors

Command executors are of the following format, where sender is a CommandSender, and args is an Object[], which represents arguments which are parsed by the CommandAPI.

new CommandAPICommand("...").executes((sender, args) -> {
    //Code here  
}).register();

With normal command executors, these do not need to return anything. By default, this will return a success value of 1 if it runs successfully, and a success value of 0 if it runs unsuccessfully, either by throwing an exception (RuntimeException) or by forcing the command to fail (See the section on handling command failures.

In short, this is what values are returned when a command is executed from a normal command executor:

Command WorksCommand Doesn't Work
Success Value10
Result Value10

Example - Creating a message broadcasting system

To illustrate this, let's take a look at a simple message broadcasting command. We declare our arguments (in this case, "message"), we provide some aliases and set a permission required to run the command. Then we declare our main command body by using the .executes() method, before finally registering the command:

// Create our arguments
LinkedHashMap<String, Argument> arguments = new LinkedHashMap<>();
arguments.put("message", new GreedyStringArgument());

//Create our command
new CommandAPICommand("broadcastmsg")
    .withArguments(arguments)                     // The arguments
    .withAliases("broadcast", "broadcastmessage") // Command aliases
    .withPermission(CommandPermission.OP)         // Required permissions
    .executes((sender, args) -> {
        String message = (String) args[0];
        Bukkit.getServer().broadcastMessage(message);
    }).register();

Note how when we finish up our implementation of .executes(), we don't return anything. This is unlike commands in the standard Bukkit API where the onCommand method returns a Boolean value:

boolean onCommand(CommandSender, Command, String, String[])

The returning of this Boolean value is handled automatically by the CommandAPI on a much lower level.

Restricting who can run your command

The CommandAPICommand has multiple different executes...() methods that can restrict the command sender to any of the following objects:

  • CommandSender - No restriction, players, the console etc. can use this command. This is what Bukkit normally uses.
  • Player - Only in-game players can run this command
  • Entity - Only entities (therefore, players as well) can run this command
  • BlockCommandSender - Only command blocks can run this command
  • ConsoleCommandSender - Only the console can run this command
  • ProxiedCommandSender - Only proxied command senders (e.g. other entities via the /execute as ... command)

This is done using the respective method:

Restricted senderMethod to use
CommandSender.executes()
Player.executesPlayer()
Entity.executesEntity()
BlockCommandSender.executesCommandBlock()
ConsoleCommandSender.executesConsole()
ProxiedCommandSender.executesProxy()

Example - A /suicide command

Say we wanted to create a command /suicide, which kills the player that executes it. Since this command isn't really "designed" for command senders that are not players, we can restrict it so only players can execute this command (meaning that the console and command blocks cannot run this command). Since it's a player, we can use the .executesPlayer() method:

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

Multiple command executor implementations

The CommandAPI allows you to chain different implementations of the command depending on the type of CommandSender. This allows you to easily specify what types of CommandSenders are required to run a command.

Extending on the suicide example above, we could write another implementation for a different CommandSender. Here, we write an implementation to make entities (non-player) go out with a bang when they run the command (using /execute as <entity> run <command> command).

Example - A /suicide command with different implementations

new CommandAPICommand("suicide")
    .executesPlayer((player, args) -> {
		player.setHealth(0);
    })
    .executesEntity((entity, args) -> {
        entity.getWorld().createExplosion(e.getLocation(), 4);
		entity.remove();
    }).register();

This saves having to use instanceof multiple times to check the type of the CommandSender.