Command Builder

This builder is intended to reduce the amount of nested Commands.literal(...) and Commands.argument(...) calls needed when registering complex command hierarchies. It wraps a root LiteralArgumentBuilder and exposes a compact API for attaching requirements, execution handlers, nested literals, and arguments.

Note

This example is from the Cobbled Level Control mod, which uses the CommandBuilder to register its commands. The register method is called from the mod’s onRegisterCommands event handler.

ExampleCommand.java

public class ExampleCommand {
  public static void register(CommandDispatcher<CommandSourceStack> dispatcher, CommandBuildContext registry, Commands.CommandSelection context) {
    dispatcher.register(
      new CommandBuilder("level-control")
        .requires(src -> PermissionHelpers.checkPermission(src, PermissionHelpers.COMMAND_ROOT_PERMISSION))
        .then("reload", reload -> reload
          .requires(src -> PermissionHelpers.checkPermission(src, PermissionHelpers.COMMAND_RELOAD_PERMISSION))
          .executes(this::reload)
        )
        .then("level-up", levelUp -> levelUp
          .requires(src -> PermissionHelpers.checkPermission(src, PermissionHelpers.COMMAND_LEVEL_UP_PERMISSION))
          .then(Commands.argument("player", ServerUserArgument.playerArg())
            .then(Commands.argument("module", StringArgumentType.string())
              .suggests(modulesProvider())
              .executes(this::levelUp)
            )
          )
        )
        .then("set-difficulty", setDifficulty -> setDifficulty
          .requires(src -> PermissionHelpers.checkPermission(src, PermissionHelpers.COMMAND_SET_DIFFICULTY_PERMISSION))
          .then(Commands.argument("player", ServerUserArgument.playerArg())
            .then(Commands.argument("difficulty", StringArgumentType.string())
              .suggests((_ctx, builder) -> {
                var diffNames = CobbledLevelControl.INSTANCE.getConfigManager().getMainConfig().difficulties;
                for (var difficulty : diffNames) {
                  builder.suggest(difficulty);
                }
                return builder.buildFuture();
              })
              .executes(this::setDifficulty)
            )
          )
        )
        .then("set-level", setLevel -> setLevel
          .requires(src -> PermissionHelpers.checkPermission(src, PermissionHelpers.COMMAND_SET_LEVEL_PERMISSION))
          .then(Commands.argument("player", ServerUserArgument.playerArg())
            .then(Commands.argument("level", IntegerArgumentType.integer(1))
              .executes(this::setLevel)
            )
          )
        )
        .then("status", status -> status
          .requires(src -> PermissionHelpers.checkPermission(src, PermissionHelpers.COMMAND_STATUS_PERMISSION))
          .executes(this::action)
        )
        .then("status-other", statusOther -> statusOther
          .requires(src -> PermissionHelpers.checkPermission(src, PermissionHelpers.COMMAND_STATUS_OTHER_PERMISSION))
          .then(Commands.argument("player", ServerUserArgument.playerArg())
            .executes(this::action)
          )
        )
        .build()
    );
  }
}