Command Executor
In traditional Bukkit plugin development, we usually use the CommandExecutor interface of Bukkit to handle commands.
However, in some cases, we need to determine whether the sender of the command is a player, whether it has certain permissions, and determine the parameters, etc.
If a plugin has multiple commands, then these judgment logic will be repeated in the processing method of each command, such code is very redundant.
In addition, we may also need to handle command errors, output help information, etc.
UltiTools-API offers a more concise way to handle commands by encapsulating the native CommandExecutor interface.
Create a command executor
Starting with v6.2.0, you should inherit the BaseCommandExecutor class and override the handleHelp method. The @CmdTarget and @CmdExecutor annotations here represent the target type and executor information of the command.
Deprecated
AbstractCommandExecutor is deprecated since v6.2.0. Use BaseCommandExecutor instead which provides the same annotation-driven features plus a pluggable validation chain, improved context management, and custom type parser support.
import com.ultikits.ultitools.abstracts.command.BaseCommandExecutor;
import com.ultikits.ultitools.annotations.command.CmdExecutor;
import com.ultikits.ultitools.annotations.command.CmdTarget;
import org.bukkit.command.CommandSender;
// Command limits executor
@CmdTarget(CmdTarget.CmdTargetType.BOTH)
@CmdExecutor(
// Command permission (optional)
permission = "ultikits.example.all",
// Command description (optional)
description = "Test command",
// Command alias
alias = {"test", "ts"},
// Whether to register manually (optional)
manualRegister = false,
// Whether to require OP permission (optional)
requireOp = false
)
public class ExampleCommand extends BaseCommandExecutor {
@Override
protected void handleHelp(CommandSender sender) {
// Send help message to command sender
}
}You have completed an empty command executor that does nothing! The @CmdTarget and @CmdExecutor annotations here represent the sender type and executor information of the command. We will introduce these two annotations in detail in the next section.
Register command
The same as spigot development, with the executor, you need to register it. We can use the getCommandManager().register() method to register the command in the registerSelf method.
If your module has a large number of command executors and you don't want to register them manually, you can also use the automatic registration provided by UltiTools, for details, please refer to this article.
import com.ultikits.plugin.ultikitsapiexample.context.ContextConfig;
import com.ultikits.ultitools.abstracts.UltiToolsPlugin;
import com.ultikits.ultitools.annotations.ContextEntry;
import com.ultikits.ultitools.annotations.EnableAutoRegister;
import java.io.IOException;
import java.util.List;
public class UltiToolsConnector extends UltiToolsPlugin {
public UltiToolsConnector(String name, String version, List<String> authors, List<String> depend, int loadPriority, String mainClass) {
super(name, version, authors, depend, loadPriority, mainClass);
}
@Override
public boolean registerSelf() throws IOException {
// register command
getCommandManager().register(this, ExampleCommand.class);
return true;
}
@Override
public void unregisterSelf() {
}
@Override
public void reloadSelf() {
super.reloadSelf();
}
}Mapping-based command executor
Quick start
Assuming that your plugin has a function to set the teleport point, you want the player to enter a command with the teleport point name, so as to set up a teleport point.
Then this command should look like this: /point add name
If you use the traditional method, you need to judge the legality of the parameter input, the sender and permissions, etc. If there are other functions, you also need to write a lot of switch ... case and if ... else statements, crazy nesting.
However, with UltiTools, you only need to write the main logic, and the rest will be handled by UltiTools.
First, you need to create an executor class that inherits BaseCommandExecutor.
Then create a method named addPoint and add the parameters you want:
public void addPoint(@CmdSender Player player, String name) {
...
}Yes, each of your functions uses a separate function without extra judgment.
If you want to get the Player object instead of the CommandSender object, then you get the Player, you don't need to judge and convert at all. You only need to add the @CmdSender annotation in front of the parameter you want to get the sender object.
Then, you only need to add the @CmdMapping annotation so that UltiTools can match your method according to the input command:
@CmdMapping(format = "add <name>")
public void addPoint(@CmdSender Player player, String name) {
...
}Finally, use @CmdParam to bind command parameters:
@CmdMapping(format = "add <name>")
public void addPoint(@CmdSender Player player, @CmdParam("name") String name) {
...
}Till now, you only need to register the command executor to complete all the work.
Tab completion
Need Tab suggestion for each command parameter, but don't want to write a lot of code?
It is a disaster to generate a completion list by judging the length of each command and the previous parameters.
Now you only need to write a method for each parameter to return a completion list! This method can be reused, and all the complicated parameter quantity judgments are left to UltiTools to complete.
What you need to do is just add the suggest attribute in the @CmdParam annotation and specify a method name.
@CmdMapping(format = "add <name>")
public void addPoint(@CmdSender Player player, @CmdParam(value = "name", suggest = "listName") String name) {
...
}
public List<String> listName(Player player, Command command, String[] args) {
...
}UltiTools will first search for matching method names in the current class and try to call this method.
Your method can contain up to three parameters, corresponding to the types Player, Command and String[]. You can choose any amount or order of parameters, but the type can only be these three types, one parameter for each type.
Player represents the player who sent the command, Command represents the current command, and String[] represents the current parameters of the current command.
Your method needs to return a value of type List<String>, and UltiTools will return this value as a completion list to the player.
TIP
If you just want to return a simple prompt string, then you only need to write the string you want in the suggest field. The string here also supports internationalization.
@CmdMapping(format = "add <name>")
public void addPoint(@CmdSender Player player,
@CmdParam(value = "name", suggest = "[name]") String name) {
...
}TIP
If you are not satisfied with the completion list generated by UltiTools, you can override the suggest method to generate the completion list yourself.
@Override
protected List<String> suggest(Player player, Command command, String[] strings) {
...
}@CmdSuggest
If you want a completion method to be shared with other command classes, you can create a class and write methods which you want to reuse in other class.
Add the @CmdSuggest annotation to the class which need to use suggestion method, and specify the suggestion class.
@CmdSuggest({PointSuggest.class})
public class PointCommand extends AbstractCommandExecutor {
@CmdMapping(format = "add <name>")
public void addPoint(@CmdSender Player player, @CmdParam(value = "name", suggest = "listName") String name) {
...
}
}public class PointSuggest {
public List<String> listName(Player player, Command command, String[] args) {
...
}
}Parameters
Command without Parameters
If a command does not require any parameters, simply leave the format value empty.
@CmdMapping(format="")This type of command can have at most one occurrence.
Variable Parameters
For the last parameter in a method, you can use an array type by adding ... to the last parameter in the format. Here's an example:
@CmdMapping(format = "add <name...>")
public void addPoint(@CmdSender Player player, @CmdParam(value = "name...") String[] name) {
...
}In this example, when a player enters /somecmd add aa bb cc, the name will be ['aa', 'bb', 'cc'].
Type Parsing
Before passing parameters to a method, UltiTools converts the command's variable parameters based on the types required by the method.
All parsers are stored in a map called parsers, and you can use getParser() to access it.
For some types, AbstractCommandExecutor provides default parsers (including base types and arrays):
- String (Java built-in)
- Float (Java built-in)
- Double (Java built-in)
- Integer (Java built-in)
- Short (Java built-in)
- Byte (Java built-in)
- Long (Java built-in)
- OfflinePlayer (Bukkit API)
- Player (Bukkit API)
- Material (Bukkit API)
- UUID (Java built-in)
- Boolean (Java built-in)
If you want to use a custom parser, you need to create a method that can be used with the Function interface.
Supported parser types are <String, ?>, meaning the method has exactly one parameter of type String and returns a value of any type.
public static SomeType toSomeType(String s) {
//do something...
return result;
}Then, add the converter in the constructor:
public SomeCommand() {
super();
getParsers().put(Arrays.asList(SomeType.class, SomeType[].class), SomeType::toSomeType);
}WARNING
Make sure to add the array type as well; otherwise, variable parameters won't be parsed.
Permission
Method permission
If you need to specify permissions for a method, you need to add the permission attribute in the @CmdMapping annotation.
@CmdMapping(..., permission = "point.set.add")TIP
The permissions specified in @CmdExecutor will override any permission set in @CmdMapping.
OP Required
If you want all methods to be executed by OP only, you need to set the requireOp attribute in @CmdExecutor to true
@CmdExecutor(..., requireOp = true)If you want a method to be executed by OP only, you need to set the requireOp attribute in @CmdMapping to true
@CmdMapping(..., requireOp = true)Sender Limitation
If you want to specify the sender for all methods, you need to add the @CmdTarget annotation in front of your class.
If you want to specify the sender for a method, just add it in front of the method.
@CmdTarget(CmdTarget.CmdTargetType.BOTH)TIP
If the sender is specified in both the class and the method, both must be met.
Asynchronous Execution
If a command needs to execute a task that takes a long time, you need to add @RunAsync in front of the corresponding
@CmdMapping(format = "list")
@RunAsync
public void listPoint(@CmdSender Player player) {
//do query
}This will create a new asynchronous thread to execute the method, avoiding blocking in the Bukkit main thread.
Since the Bukkit API does not allow asynchronous calls, if you need to call the Bukkit API, you need to create a synchronous task:
@CmdMapping(format = "list")
@RunAsync
public void listPoint(@CmdSender Player player) {
//do query
new BukkitRunnable() {
@Override
public void run() {
//call bukkit api
}
}.runTask(PluginMain.getInstance());
}Command cooldown
If you don't want a command to be executed in large quantities and consume server resources, then you can add @CmdCD in front of the corresponding method:
@CmdCD(60)Parameter type is integer, in second.
If the command is executed before the cooldown ends, the message Frequent operations, please try again later will be sent.
This restriction only takes effect on players.
Execution lock
If you want a command to be executed only one by one, you can add @UsageLimit in front of the corresponding method:
@UsageLimit(ContainConsole = false, value = LimitType.SENDER)ContainConsole is whether the restriction is applied to the console, and value is the restriction type.
Available types are:
LimitType.SENDERlimits that each sender can only have one command of this type executed at a timeLimitType.ALLlimits that only one command of this type can be executed in the whole serverLimitType.NONEno limit
Under the LimitType.SENDER strategy, the player will receive a prompt: Please wait for last Command Processing!
Under the LimitType.ALL strategy, the player will receive a prompt: Please wait for last Command Processing which sent by other players!
Command Context
The CommandContext is an immutable object that encapsulates all information about a command invocation. It is passed to validators and is useful for accessing command metadata during execution.
Accessing Context Information
// Check if sender is a player
boolean isPlayer = context.isPlayer();
// Get the player (returns null if sender is not a player)
Player player = context.getPlayer();
// Get the raw command sender
CommandSender sender = context.getSender();
// Get the command and its alias
Command command = context.getCommand();
String alias = context.getAlias();
// Get raw arguments
String[] args = context.getRawArgs();
int argCount = context.getArgCount();
String firstArg = context.getArg(0);
// Get parsed parameters by name
String[] nameValues = context.getParam("name");
String singleValue = context.getParamValue("name");
// Get the matched method and format
Method method = context.getMatchedMethod();
String format = context.getMatchedFormat();
// Get command invocation timestamp
long timestamp = context.getTimestamp();Command Validation Chain
The validation chain implements the Chain of Responsibility pattern, allowing you to compose multiple validators that execute in order. Built-in validators handle common requirements like permissions, sender type, cooldowns, and execution locks.
Built-in Validators
SenderTypeValidator
Validates that the command sender matches the expected target type (player, console, or both):
@CmdTarget(CmdTarget.CmdTargetType.PLAYER)
@CmdExecutor(alias = {"mycmd"})
public class PlayerOnlyCommand extends BaseCommandExecutor {
// Automatically rejects console users
}PermissionValidator
Validates that the sender has required permissions:
@CmdExecutor(
alias = {"admin"},
permission = "myadmin.use", // Base permission for all commands
requireOp = false
)
@CmdMapping(format = "reload", permission = "myadmin.reload") // Method-specific permission
public void reload(@CmdSender CommandSender sender) {
// Only users with "myadmin.reload" can execute this
}CooldownValidator
Manages per-player command cooldowns using @CmdCD:
@CmdMapping(format = "expensive")
@CmdCD(30) // 30 second cooldown
public void expensiveOperation(@CmdSender Player player) {
// Performs expensive operation
// Player must wait 30 seconds before executing again
}Access cooldown state programmatically:
@Autowired
private CooldownValidator cooldownValidator;
public void checkCooldown(UUID playerId, String methodKey) {
long remaining = cooldownValidator.getRemainingCooldown(playerId, methodKey);
if (remaining > 0) {
// Player is on cooldown
}
}UsageLockValidator
Prevents concurrent execution using @UsageLimit:
@CmdMapping(format = "backup")
@UsageLimit(value = UsageLimit.LimitType.ALL) // Only one per server
public void backup(@CmdSender CommandSender sender) {
// Only one player can run this at a time
}
@CmdMapping(format = "download")
@UsageLimit(value = UsageLimit.LimitType.SENDER) // One per player
public void download(@CmdSender Player player) {
// Each player can only run one at a time
}Creating Custom Validators
Implement CommandValidator to create custom validation logic:
public class WorldRestrictionValidator implements CommandValidator {
private final Set<String> allowedWorlds = new HashSet<>();
public WorldRestrictionValidator(String... worlds) {
allowedWorlds.addAll(Arrays.asList(worlds));
}
@Override
public ValidationResult validate(CommandContext context) {
if (!context.isPlayer()) {
return ValidationResult.success();
}
Player player = context.getPlayer();
if (!allowedWorlds.contains(player.getWorld().getName())) {
return ValidationResult.failure(
"You can only use this command in: " + String.join(", ", allowedWorlds),
"command.error.wrong_world"
);
}
return ValidationResult.success();
}
@Override
public int getOrder() {
return 400; // Execute after permission validators
}
@Override
public String getName() {
return "WorldRestrictionValidator";
}
}Register the validator in your command executor:
public class MyCommand extends BaseCommandExecutor {
public MyCommand() {
super();
addValidator(new WorldRestrictionValidator("world", "world_nether"));
}
}Or use a custom validator chain:
ValidatorChain chain = ValidatorChain.builder()
.add(SenderTypeValidator.fromAnnotation(null))
.add(new PermissionValidator("myadmin.use", false))
.add(new WorldRestrictionValidator("world"))
.build();
public class MyCommand extends BaseCommandExecutor {
public MyCommand() {
super(chain);
}
}Validator Execution Order
Validators execute in order by their getOrder() value (lower values first):
- 100 - SenderTypeValidator (ensure right user type)
- 200 - PermissionValidator (check permissions)
- 250 - UsageLockValidator (prevent concurrent execution)
- 300 - CooldownValidator (check cooldown state)
- 400+ - Custom validators
Async Commands
Use @AsyncCommand to execute commands asynchronously without blocking the server thread. This is cleaner than the deprecated @RunAsync:
@CmdMapping(format = "backup")
@AsyncCommand
public void backupWorld(@CmdSender Player player) {
// Runs asynchronously - safe for I/O operations
performBackupLogic();
// Sync back to main thread for Bukkit operations
Bukkit.getScheduler().runTask(UltiTools.getInstance(), () -> {
player.sendMessage("Backup completed!");
});
}Async Command Options
@AsyncCommand(
showProcessing = true, // Show "Processing..." message
processingMessageKey = "command.backup.processing", // Custom i18n message
timeout = 60 // 60 second timeout (0 = no timeout)
)
@CmdMapping(format = "backup")
public void backupWorld(@CmdSender Player player) {
// Configuration above:
// - Shows "处理中..." while executing
// - Uses custom i18n key instead of default
// - Cancels if execution takes > 60 seconds
}Custom Type Parsers
Type parsers convert command argument strings into the types your methods require. UltiTools provides built-in parsers for primitive types, Bukkit entities, and arrays.
Built-in Parsers
- Primitive types: String, Integer, Double, Float, Long, Short, Byte, Boolean
- Bukkit entities: Player, OfflinePlayer, Material, World
- Other types: UUID, Location, GameMode, Enchantment
- Arrays: All types above support array syntax
Creating Custom Parsers
Implement TypeParser<T>:
public class ColorParser implements TypeParser<Color> {
@Override
public Class<Color> getPrimaryType() {
return Color.class;
}
@Override
public List<Class<?>> getSupportedTypes() {
return Arrays.asList(Color.class, Color[].class);
}
@Override
public Color parse(String value) throws TypeParseException {
try {
// Parse hex color like "FF0000"
int rgb = Integer.parseInt(value, 16);
return Color.fromRGB(rgb);
} catch (NumberFormatException e) {
throw new TypeParseException(value, Color.class,
"Invalid color format. Use hexadecimal (e.g., FF0000)", e);
}
}
@Override
public int getPriority() {
return 0;
}
}Register the parser:
@Autowired
private UltiToolsPlugin plugin;
@PostConstruct
public void init() {
TypeParserRegistry.getInstance().register(new ColorParser());
}Use in your command:
@CmdMapping(format = "setcolor <color>")
public void setColor(@CmdSender Player player, @CmdParam("color") Color color) {
// color is parsed automatically
}Advanced parser with array support:
public class RangeParser implements TypeParser<IntRange> {
@Override
public Class<IntRange> getPrimaryType() {
return IntRange.class;
}
@Override
public List<Class<?>> getSupportedTypes() {
return Arrays.asList(IntRange.class, IntRange[].class);
}
@Override
public IntRange parse(String value) throws TypeParseException {
String[] parts = value.split("-");
if (parts.length != 2) {
throw new TypeParseException(value, IntRange.class,
"Range format: min-max (e.g., 1-100)");
}
try {
int min = Integer.parseInt(parts[0]);
int max = Integer.parseInt(parts[1]);
return new IntRange(min, max);
} catch (NumberFormatException e) {
throw new TypeParseException(value, IntRange.class,
"Range bounds must be integers", e);
}
}
}
// Usage
@CmdMapping(format = "random <range>")
public void randomNumber(@CmdSender Player player,
@CmdParam("range") IntRange range) {
int value = ThreadLocalRandom.current().nextInt(range.min, range.max + 1);
player.sendMessage("Random: " + value);
}Vanilla Bukkit Command Executor Wrapper
Player Command
If you want a command to be executed only in the game (executed by the player), you can inherit the AbstractPlayerCommandExecutor class and override the onPlayerCommand method.
public class SomeCommands extends AbstractPlayerCommandExecutor {
@Override
protected boolean onPlayerCommand(Command command, String[] strings, Player player) {
// your code
return true;
}
}Except for the Player type parameter, this method is the same as the CommandExecutor#onCommand method.
If you try to execute this command in the console, you will receive an error message: This command can only be performed in GAME!
If you want this command to use Tab completion, please see the next section.
Command Completion
From Minecraft 1.13, the Bukkit API provides a new TabCompleter interface for command completion.
UltiTools has encapsulated this interface to provide a more concise way of command completion.
You need to inherit the AbstractTabExecutor class and override the onTabComplete method.
@Override
protected List<String> onPlayerTabComplete(Command command, String[] strings, Player player) {
// your code
return null;
}Except for the Player type parameter, this method is the same as the TabCompleter#onTabComplete method.
The rest of the usage is the same as the AbstractPlayerCommandExecutor class.
Console Command
If you want a command to be executed only in the console, you can inherit the AbstractConsoleCommandExecutor class and override the onConsoleCommand method.
public class SomeCommands extends AbstractConsoleCommandExecutor {
@Override
protected boolean onConsoleCommand(CommandSender commandSender, Command command, String[] strings) {
// your code
return true;
}
}This method is the same as the CommandExecutor#onCommand method.
If you try to execute this command in the game, you will receive an error message: This command can only be performed in CONSOLE!
Help Message
All three classes above provide a sendHelpMessage method for sending help messages to players or consoles.
sendHelpMessage(CommandSender sender) {
// send help message
}When sending the /somecommand help command, this method will be called.
Error Message
You may find that the onCommand method of the three classes above returns a boolean type value.
It is the same as the native CommandExecutor interface, this value is used to indicate whether the command was executed successfully.
When the command execution returns false, the command sender will be automatically prompted with an error message.
Contributors
Ling Bao
Claude Opus 4.6