Parameter Types

What Are Parameter Types?

These is how the framework handles your arguments. I'll start by showing examples:

@Command("cmd")
public class CommandTest extends BaseCommand {

    @SubCommand("material")
    public void selectMaterial(final CommandSender sender, final Material material) {
        if (material == null) {
            // error message here
            return;
        }

        sender.sendMessage(material.getName());
    }

}

The class and method above would be the same as someone typing the following in game: /cmd material DIAMOND_ORE. The second parameter is of the type enum. It is automatically checked if the player selected a valid material and passes it to your command method. It is important to check for NULL, as if the value entered by the player doesn't exist, it'll return NULL. This is on purpose and it's for easily handling your errors instead of relying on unnecessary message registering. Currently MF supports diverse number of parameter types by default.

Default Types

• Short

• Integer

• Long

• Float

• Double

• String

• String[]

• Player

• Material

• Boolean

• Sound

• boolean

• World

Due to the resolver returning null for invalid entries for easy error handling you cannot use primitive types when handling numbers as int/double/etc, it will will give you an error.

Registering Parameter

Need a parameter that is not accepted? Simply register it! For this let's give an example let's register a Entity that we get by it's UUID. On our onEnable method we get our CommandManager to register it. We first need to get theParameterHandler.

commandManager.getParameterHandler().register(Entity.class, argument -> {
    // Gets the entity from the UUID
    final Entity entity = Bukkit.getEntity(UUID.fromString(String.valueOf(argument)));
    // Checks if the entity is null or not and returns only the argument used
    if (entity == null) return new TypeResult(argument);
    // Returns the entity found and the argument
    return new TypeResult(entity, argument);
});

Entity.class is the class type you want to register, the argument is the argument the player just typed, you can use it to check if it is what you want it to be. We then return a TypeResult bject, which has two constructors, one that will accept an object in our case the entity and the other is the argument, the second is just for the argument, meaning the first object is null. This is useful for later to handle errors as if the entity is null it doesn't exist. It allows you to both handle your errors in the command class and also to get the raw value of the command typed, making it possible for you to have case specific error messages in your command class. By registering a new parameter with the same Class as an existing one, you can override it.

Don't wish to use it?

If you don't want to use parameters like this and prefer to have more freedom then simply use String[] as your second parameter. This would be the most basic command handling, where you can handle everything by yourself.

@SubCommand("subcommand")
public void subCommand(final CommandSender sender, final String[] args) {
    // Handle the arguments yourself here
}