tutorial:commands
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+ | Licensing: The code in this article is licensed under the " | ||
+ | |||
====== Creating Commands ====== | ====== Creating Commands ====== | ||
- | Creating commands can allow a mod developer to add functionality that a player | + | Creating commands can allow a mod developer to add functionality that can used through a command. This tutorial will teach you how to register commands, and the general |
- | This tutorial will teach you how to register commands, and the command structure of Brigadier | + | |
- | ===== Registering Commands | + | ===== What is Brigadier? |
- | If you just want to see how to register | + | Brigadier is a command parser & dispatcher written by Mojang for use in Minecraft. Brigadier is a tree based command library where you build a tree of arguments and commands. |
- | Registering commands is done through '' | + | The source code for brigadier can be found here: https:// |
- | The '' | + | ===== The '' |
- | The dedicated flag if set to true will tell Fabric to only register the command on a '' | + | In Minecraft, '' |
- | Below are a few examples | + | The single method in '' |
- | <code java [enable_line_numbers=" | + | Like other functional interfaces, it is usually used as a lambda or a method |
- | CommandRegistry.INSTANCE.register(false, dispatcher -> TutorialCommands.register(dispatcher)); | + | |
- | + | ||
- | CommandRegistry.INSTANCE.register(false, | + | |
- | TutorialCommand.register(dispatcher); | + | |
- | TutorialHelpCommand.register(dispatcher); | + | |
- | }); | + | |
- | + | ||
- | CommandRegistry.INSTANCE.register(true, | + | |
- | dispatcher.register(LiteralArgumentBuilder.literal(" | + | |
- | }); | + | |
- | </ | + | |
- | ==== A very basic command ==== | + | <code java> |
- | + | Command< | |
- | Wait isn't this the exact same command from the Brigadier tutorial? Well yes it is but it is here to help explain the structure of a command. | + | return |
- | + | }; | |
- | <code java [enable_line_numbers=" | + | |
- | // The root of the command. This must be a literal argument. | + | |
- | dispatcher.register(CommandManager.literal(" | + | |
- | // Then add an argument named bar that is an integer | + | |
- | .then(CommandManager.argument(" | + | |
- | // The command to be executed if the command " | + | |
- | .executes(ctx | + | |
- | System.out.println(" | + | |
- | // Return a result. -1 is failure, 0 is a pass and 1 is success. | + | |
- | return 1; | + | |
- | })) | + | |
- | | + | |
- | .executes(ctx -> { | + | |
- | System.out.println(" | + | |
- | | + | |
- | }) | + | |
- | ); | + | |
</ | </ | ||
- | The main process registers the command " | + | The integer can be considered |
- | Since the root node must be literal, The sender must enter the exact same sequence | + | |
- | ===== Brigadier Explained ===== | ||
- | Brigadier starts with the '' | + | ==== What can the ServerCommandSource do? ==== |
- | The trunk of the tree is the CommandDispatcher. | + | |
- | The register(LiteralArgumentBuilder) methods specify the beginning of branches with the following then methods specifying the shape of length of the branches. | + | |
- | The executes blocks | + | |
- | The execute blocks specify the command to be ran. As Brigadier's Command is a FunctionalInterface you can use lambdas | + | A '' |
- | ==== CommandContexts ==== | ||
- | |||
- | When a command is ran, Brigadier provides a CommandContext to the command that is ran. | ||
- | The CommandContext contains all arguments and other objects such as the inputted String and the '' | ||
- | |||
- | ==== Arguments ==== | ||
- | |||
- | The arguments in Brigadier both parse and error check any inputted arguments. | ||
- | Minecraft creates some special arguments for it's own use such as the '' | ||
- | |||
- | You could do the long method of typing '' | ||
- | This also works for getting arguments, which shortens the already long '' | ||
- | This also works for Minecraft' | ||
- | |||
- | And your imports would look something like this: | ||
<code java [enable_line_numbers=" | <code java [enable_line_numbers=" | ||
- | import static com.mojang.brigadier.arguments.StringArgumentType.getString; | + | // Get the source. This will always work. |
- | import static com.mojang.brigadier.arguments.StringArgumentType.word; | + | final ServerCommandSource source = ctx.getSource(); |
- | import static net.minecraft.server.command.CommandManager.literal; | + | |
- | import static net.minecraft.server.command.CommandManager.argument; // argument(" | + | |
- | import static net.minecraft.server.command.CommandManager.*; | + | |
- | </ | + | |
- | Brigadier' | + | // Unchecked, may be null if the sender was the console or the command block. |
+ | final @Nullable Entity sender = source.getEntity(); | ||
- | Minecraft' | + | // Will throw an exception if the executor of the command was not an Entity. |
+ | // The result of this could contain a player. Also will send feedback telling the sender of the command | ||
+ | // This method will require your methods to throw a CommandSyntaxException. | ||
+ | // The entity options in ServerCommandSource could return a CommandBlock entity, any living entity or a player. | ||
+ | final @NotNull Entity sender2 = source.getEntityOrThrow(); | ||
- | ==== Suggestions ==== | + | // null if the executor of the command is not a player. |
+ | final @Nullable ServerPlayerEntity player | ||
- | Suggestions can be provided to the client to recommend what to input into the command. | + | // Will throw an exception if the executor of the command |
- | < | + | // Also will send feedback telling |
- | SUMMONABLE_ENTITIES | + | // This method will require your methods to throw a CommandSyntaxException. |
- | AVAILIBLE_SOUNDS | + | final @NotNull ServerPlayerEntity player = source.getPlayerOrThrow(); |
- | ALL_RECIPES | + | |
- | ASK_SERVER | + | |
- | </code> | + | |
- | Loot tables specify their own SuggestionProvider inside LootCommand for example. | + | // Gets the sender' |
+ | // This could be the location of the entity/ | ||
+ | final Vec3d position = source.getPosition(); | ||
- | The example below is a dynamically changing SuggestionProvider that lists several words for a StringArgumentType to demonstrate how it works: | + | // Gets the world the sender |
- | <code java [enable_line_numbers=" | + | final ServerWorld world = source.getWorld(); |
- | public static SuggestionProvider< | + | |
- | return (ctx, builder) -> getSuggestionsBuilder(builder, | + | |
- | } | + | |
- | + | ||
- | private static CompletableFuture< | + | |
- | String remaining = builder.getRemaining().toLowerCase(Locale.ROOT); | + | |
- | + | ||
- | if(list.isEmpty()) { // If the list is empty then return no suggestions | + | |
- | return Suggestions.empty(); // No suggestions | + | |
- | } | + | |
- | + | ||
- | for (String str : list) { // Iterate through | + | |
- | if (str.toLowerCase(Locale.ROOT).startsWith(remaining)) { | + | |
- | | + | |
- | } | + | |
- | } | + | |
- | return builder.buildFuture(); | + | |
- | } | + | |
- | </ | + | |
- | The SuggestionProvider is a FunctionalInterface that returns a CompletableFuture containing a list of suggestions. These suggestions are given to client | + | // Gets the sender' |
+ | final Vec2f rotation = source.getRotation(); | ||
- | Though remember these are suggestions. The inputted command may not contain an argument you suggested so you still have to parse check inside | + | // Access |
+ | final MinecraftServer server = source.getServer(); | ||
- | To use the suggestion you would append it right after the argument you want to recommend arguments for. This can be any argument and the normal client side exception popups will still work. Note this cannot be applied to literals. | + | // The name of the command source. This could be the name of the entity, player, |
+ | // the name of a CommandBlock that has been renamed before being placed down, or in the case of the Console, " | ||
+ | final String name = source.getName(); | ||
- | <code java [enable_line_numbers=" | + | // Returns |
- | argument(argumentName, word()) | + | // This is based on the operator status of the sender. |
- | .suggests(CompletionProviders.suggestedStrings()) | + | // (On an integrated server, the player must have cheats enabled to execute these commands.) |
- | .then(/*Rest of the command*/)); | + | final boolean b = source.hasPermissionLevel(int level); |
</ | </ | ||
- | ==== Requires | + | ===== Register a basic command ===== |
- | Lets say you have a command you only want operators to be able to execute. This is where the '' | + | Commands are registered by registering in '' |
- | For example this may look like the following: | + | The event should be registered in your mod's initializer. The callback has three parameters. The '' |
- | <code java [enable_line_numbers=" | + | To simplify the code, it is highly recommended to '' |
- | dispatcher.register(literal(" | + | <code java> |
- | .requires(source -> source.hasPermissionLevel(4)) | + | import static net.minecraft.server.command.CommandManager.*; |
- | .executes(ctx -> { | + | |
- | ctx.getSource().sendFeedback(new LiteralText(" | + | |
- | return 1; | + | |
- | }); | + | |
</ | </ | ||
- | This command will only execute if the Source of the command is a level 4 operator at minimum. If the predicate returns false, then the command | + | In the mod initializer, we just register |
- | + | ||
- | ==== Exceptions ==== | + | |
- | + | ||
- | Brigadier supports command exceptions which can be used to end a command such as if an argument didn't parse properly or the command failed to execute. | + | |
- | + | ||
- | All the exceptions from Brigadier are based on the CommandSyntaxException. The two main types of exceptions Brigadier provides are Dynamic and Simple exception types, of which you must '' | + | |
- | Below is a coin flip command to show an example of exceptions in use. | + | |
<code java [enable_line_numbers=" | <code java [enable_line_numbers=" | ||
- | dispatcher.register(CommandManager.literal(" | + | public class ExampleMod implements ModInitializer { |
- | .executes(ctx -> { | + | @Override |
- | Random random = new Random(); | + | public void onInitialize() { |
- | + | CommandRegistrationCallback.EVENT.register((dispatcher, | |
- | if(random.nextBoolean()) { // If heads succeed. | + | .executes(context |
- | ctx.getSource().sendMessage(new TranslateableText("coin.flip.heads")) | + | // For versions below 1.19, replace |
- | return Command.SINGLE_SUCCESS; | + | |
- | } | + | |
- | throw | + | |
- | })); | + | |
- | </ | + | |
- | + | ||
- | Though you are not just limited to a single type of exception as Brigadier also supplies Dynamic exceptions. | + | |
- | + | ||
- | <code java [enable_line_numbers="true" | + | |
- | DynamicCommandExceptionType used_name = new DynamicCommandExceptionType(name -> { | + | |
- | return new LiteralText("The name: " + (String) name + " has been used" | + | |
- | }); | + | |
- | </ | + | |
- | + | ||
- | There are more Dynamic exception types which each take a different amount of arguments into account ('' | + | |
- | You should remember that the Dynamic exceptions takes an object as an argument so you may have to cast the argument for your use. | + | |
- | + | ||
- | ==== Redirects | + | |
- | + | ||
- | Redirects are Brigadier' | + | |
- | + | ||
- | <code java [enable_line_numbers=" | + | |
- | public static void register(CommandDispatcher< | + | |
- | LiteralCommandNode node = registerMain(dispatcher); // Registers main command | + | |
- | dispatcher.register(literal(" | + | |
- | .redirect(node)); | + | |
- | dispatcher.register(literal(" | + | |
- | .redirect(node)); // Alias 2, redirect to main command | + | |
- | } | + | |
- | public static LiteralCommandNode registerMain(CommandDispatcher< | + | return 1; |
- | | + | |
- | .then(argument(" | + | } |
- | .then(argument(" | + | |
- | .executes(ctx -> { | + | |
- | return execute(ctx.getSource(), | + | |
- | })))); | + | |
} | } | ||
</ | </ | ||
- | The redirect registers a branch into the command tree, where the dispatcher is told when executing a redirected command to instead look on a different branch for more arguments and executes blocks. The literal | + | **Please ensure you import |
- | Redirects do not work in shortened aliases such as '' | + | In the '' |
- | ==== Redirects (Chainable Commands) ==== | + | If the command fails, instead of calling |
- | Commands such as '' | + | |
- | <code java [enable_line_numbers=" | + | To execute this command, you must type ''/ |
- | LiteralCommandNode< | + | |
- | LiteralCommandNode< | + | |
- | // You can register under the same literal more than once, it will just register new parts of the branch as shown below if you register a duplicate branch an error will popup in console warning of conflicting commands but one will still work. | + | |
- | .then(literal(" | + | |
- | .then(literal(" | + | |
- | .redirect(root)) | + | |
- | .then(literal(" | + | |
- | .redirect(root))) | + | |
- | .then(literal(" | + | |
- | .executes(ctx -> { | + | |
- | ctx.getSource().sendFeedback(new LiteralText(" | + | |
- | return Command.SINGLE_SUCCESS; | + | |
- | }))); | + | |
- | </ | + | |
- | The redirect can also modify | + | |
- | <code java [enable_line_numbers=" | + | ===== Registration environment ===== |
- | .redirect(rootNode, (commandContext_1x) -> { | + | If desired, you can also make sure a command is only registered under some specific circumstances, for example, only in the dedicated environment: |
- | return ((ServerCommandSource) commandContext_1x.getSource()).withLookingAt(Vec3ArgumentType.getVec3(commandContext_1x, " | + | |
- | }) | + | |
- | </ | + | |
- | ===== ServerCommandSource ===== | + | < |
+ | public class ExampleCommandMod implements ModInitializer { | ||
+ | @Override | ||
+ | public void onInitialize() { | ||
+ | CommandRegistrationCallback.EVENT.register((dispatcher, | ||
+ | if (environment.field_25423) { | ||
+ | ...; | ||
+ | } | ||
+ | }); | ||
+ | } | ||
+ | } | ||
+ | </ | ||
- | What if you wanted | + | ===== Static Imports ===== |
+ | In the example above, the use of static imports is used for code simplifying. For a literal this would shorten | ||
+ | Below is an example of some static imports: | ||
<code java [enable_line_numbers=" | <code java [enable_line_numbers=" | ||
- | ServerCommandSource source = ctx.getSource(); | + | // getString(ctx, " |
- | // Get the source. This will always work. | + | import static com.mojang.brigadier.arguments.StringArgumentType.getString; |
- | + | // word() | |
- | Entity sender = source.getEntity(); | + | import static com.mojang.brigadier.arguments.StringArgumentType.word; |
- | // Unchecked, may be null if the sender was the console. | + | // |
- | + | import static net.minecraft.server.command.CommandManager.literal; | |
- | Entity sender2 = source.getEntityOrThrow(); | + | // |
- | // Will end the command if the source of the command was not an Entity. | + | import static net.minecraft.server.command.CommandManager.argument; |
- | // The result of this could contain a player. Also will send feedback telling the sender of the command | + | // Import everything in the CommandManager |
- | // This method will require your methods to throw a CommandSyntaxException. | + | import static net.minecraft.server.command.CommandManager.*; |
- | // The entity options in ServerCommandSource could return a CommandBlock entity, any living entity or a player. | + | |
- | + | ||
- | ServerPlayerEntity player = source.getPlayer(); | + | |
- | // Will end the command if the source of the command was not explicitly a Player. Also will send feedback telling the sender of the command | + | |
</ | </ | ||
- | The ServerCommandSource also provides other information about the sender | + | Note: Please be sure you use the '' |
- | <code java [enable_line_numbers=" | + | Brigadier' |
- | source.getPosition(); | + | |
- | // Get' | + | |
- | source.getWorld(); | + | Minecraft' |
- | // Get' | + | |
- | source.getRotation(); | + | ===== Add Requirements ===== |
- | // Get's the sender' | + | |
- | source.getMinecraftServer(); | + | Let's say you have a command that you only want operators |
- | // Access | + | |
- | source.getName(); | + | For example this may look like the following: |
- | // The name of the command source. This could be the name of the entity, player, the name of a CommandBlock that has been renamed before being placed down or in the case of the Console, " | + | |
- | + | ||
- | source.hasPermissionLevel(int level); | + | |
- | // Returns true if the source of the command has a certain permission level. This is based on the operator status of the sender. (On an integrated server, the player must have cheats enabled to execute these commands) | + | |
- | </ | + | |
- | + | ||
- | ===== Some actual examples ===== | + | |
- | + | ||
- | Just a few to show: | + | |
- | + | ||
- | === Broadcast a message === | + | |
- | + | ||
- | <code java [enable_line_numbers=" | + | |
- | public static void register(CommandDispatcher< | + | |
- | dispatcher.register(literal(" | + | |
- | .requires(source -> source.hasPermissionLevel(2)) // Must be a game master to use the command. Command will not show up in tab completion or execute to non op's or any op that is permission level 1. | + | |
- | .then(argument(" | + | |
- | .then(argument(" | + | |
- | .executes(ctx -> broadcast(ctx.getSource(), | + | |
- | } | + | |
- | + | ||
- | public static int broadcast(ServerCommandSource source, Formatting formatting, String message) { | + | |
- | Text text = new LiteralText(message).formatting(formatting); | + | |
- | + | ||
- | source.getMinecraftServer().getPlayerManager().broadcastChatMessage(text, | + | |
- | return Command.SINGLE_SUCCESS; | + | |
- | } | + | |
- | </ | + | |
- | + | ||
- | === / | + | |
- | + | ||
- | First the basic code where we register " | + | |
<code java [enable_line_numbers=" | <code java [enable_line_numbers=" | ||
- | public static LiteralCommandNode register(CommandDispatcher< | + | dispatcher.register(literal(" |
- | return | + | .requires(source |
- | .executes(ctx -> giveDiamond(ctx))); | + | .executes(ctx -> { |
- | } | + | ctx.getSource().sendFeedback(() -> Text.literal("You are an operator"), false); |
- | </ | + | |
- | + | ||
- | Then since we only want to give to players, we check if the CommandSource is a player. But we can use '' | + | |
- | + | ||
- | <code java [enable_line_numbers=" | + | |
- | public static int giveDiamond(CommandContext< | + | |
- | | + | |
- | + | ||
- | PlayerEntity self = source.getPlayer(); // If not a player than the command ends | + | |
- | </code> | + | |
- | + | ||
- | Then we add to the player' | + | |
- | + | ||
- | <code java [enable_line_numbers=" | + | |
- | if(!player.inventory.insertStack(new ItemStack(Items.DIAMOND))){ | + | |
- | throw new SimpleCommandExceptionType(new TranslateableText("inventory.isfull")).create(); | + | |
- | } | + | |
return 1; | return 1; | ||
- | } | + | |
</ | </ | ||
- | === Antioch === | + | This command will only execute if the source of the command is a level 2 operator at minimum, // |
- | ...lobbest thou thy Holy Hand Grenade | + | |
- | who being naughty | + | |
- | Aside from the joke this command | + | To create commands that only level 4 operators (//not including// |
- | First create an entry into the CommandDispatcher that takes a literal of antioch with an optional argument of the location to summon the entity at. | + | ===== Arguments ===== |
- | <code java [enable_line_numbers=" | + | Arguments are used in most of commands. Sometimes they can be optional, which means if you do not provide that argument, the command will also run. One node may have multiple argument types, but be aware that there is possibility of ambiguity, which should be avoided. |
- | public static void register(CommandDispatcher< | + | |
- | dispatcher.register(literal(" | + | |
- | .then(required(" | + | |
- | .executes(ctx -> antioch(ctx.getSource(), BlockPosArgument.getBlockPos(ctx, " | + | |
- | .executes(ctx -> antioch(ctx.getSource(), | + | |
- | } | + | |
- | </ | + | |
- | Then the creation | + | In this case, we add one integer argument, |
- | <code java [enable_line_numbers=" | + | <code java> |
- | public static int antioch(ServerCommandSource source, BlockPos blockPos) throws CommandSyntaxException { | + | |
- | + | .then(argument(" | |
- | | + | |
- | | + | final int value = IntegerArgumentType.getInteger(context, " |
- | } | + | final int result = value * value; |
- | + | | |
- | TntEntity tnt = new TntEntity(source.getWorld(), blockPos.getX(), | + | return |
- | + | }))); | |
- | | + | |
- | source.getMinecraftServer().getPlayerManager().broadcastChatMessage(new LiteralText(" | + | |
- | | + | |
- | | + | |
- | } | + | |
</ | </ | ||
- | === Finding Biomes via Command === | + | In this case, after the word ''/ |
- | This example shows examples of redirects, exceptions, suggestions | + | Note: for simplicity, '' |
- | <code java [enable_line_numbers=" | + | |
- | public class CommandLocateBiome { | + | |
- | // First make method to register | + | |
- | public | + | |
- | LiteralCommandNode< | + | |
- | .then(argument(" | + | |
- | .then(argument(" | + | |
- | .executes(ctx -> execute(ctx.getSource(), | + | |
- | .executes(ctx -> execute(ctx.getSource(), | + | |
- | // Register redirect | + | |
- | dispatcher.register(literal(" | + | |
- | .redirect(basenode)); | + | |
- | } | + | |
- | // Beginning of the method | + | |
- | private | + | |
- | Biome biome = Registry.BIOME.get(biomeId); | + | |
- | + | ||
- | if(biome == null) { // Since the argument is an Identifier we need to check if the identifier actually exists | + | |
- | throw new SimpleCommandExceptionType(new TranslatableText(" | + | |
- | } | + | |
- | + | ||
- | List< | + | |
- | bio.add(biome); | + | |
- | + | ||
- | ServerWorld world = source.getWorld(); | + | |
- | + | ||
- | BiomeSource bsource = world.getChunkManager().getChunkGenerator().getBiomeSource(); | + | |
- | + | ||
- | BlockPos loc = new BlockPos(source.getPosition()); | + | |
- | // Now here is the heaviest part of the method. | + | |
- | BlockPos pos = bsource.locateBiome(loc.getX(), | + | |
- | + | ||
- | // Since this method can return null if it failed | + | |
- | if(pos == null) { | + | |
- | throw new SimpleCommandExceptionType(new TranslatableText(" | + | |
- | } | + | |
- | + | ||
- | int distance = MathHelper.floor(getDistance(loc.getX(), | + | |
- | // Popup text that can suggest commands. This is the exact same system that /locate uses. | + | |
- | Text teleportButtonPopup = Texts.bracketed(new TranslatableText(" | + | |
- | style_1x.setColor(Formatting.GREEN).setClickEvent(new ClickEvent(ClickEvent.Action.SUGGEST_COMMAND, | + | |
- | }); | + | |
- | + | ||
- | source.sendFeedback(new TranslatableText(" | + | |
- | return 1; | + | Then we add an optional second argument: |
- | } | + | <code java> |
- | | + | |
- | | + | .then(argument(" |
- | int int_5 = int_3 - int_1; | + | .executes(context -> { |
- | int int_6 = int_4 - int_2; | + | |
- | + | | |
- | return MathHelper.sqrt((float) (int_5 * int_5 + int_6 * int_6)); | + | |
- | } | + | |
- | + | | |
- | + | .then(argument("value2", | |
- | + | .executes(context | |
- | public static class BiomeCompletionProvider { | + | final int value = IntegerArgumentType.getInteger(context, |
- | // This provides suggestions of what biomes can be selected. Since this uses the registry, mods that add new biomes will work without modification. | + | final int value2 = IntegerArgumentType.getInteger(context, " |
- | public static final SuggestionProvider< | + | final int result = value * value2; |
- | | + | context.getSource().sendFeedback(() -> Text.literal("%s × %s = %s".formatted(value, value2, result)), false); |
- | return | + | return |
- | }); | + | })))); |
- | + | ||
- | } | + | |
</ | </ | ||
- | ===== Custom Arguments ===== | + | Now you can type one or two integers. If you give one integer, that square of integer will be calculated. If you provide two integers, their product will be calculated. You may find it unnecessary to specify similar executions twice. Therefore, we can create a method that will be used in both executions. |
- | Brigadier has support for custom argument types and this section goes into showing how to create a simple argument type. | ||
- | |||
- | Warning: Custom arguments require client mod installation to be registered correctly! If you are making a server plugin, consider using existing argument type and a custom suggestions provider instead. | ||
- | |||
- | For this example we will create a UUIDArgumentType. | ||
- | |||
- | First create a class which extends '' | ||
- | |||
- | <code java [enable_line_numbers=" | ||
- | public class UUIDArgumentType implements ArgumentType< | ||
- | </ | ||
- | |||
- | ArgumentType requires you to implement the '' | ||
<code java> | <code java> | ||
- | @Override | + | public class ExampleMod implements ModInitializer { |
- | public | + | |
- | </code> | + | public |
+ | | ||
+ | .then(argument(" | ||
+ | .executes(context -> executeMultiply(IntegerArgumentType.getInteger(context, | ||
+ | .then(argument(" | ||
+ | .executes(context -> executeMultiply(IntegerArgumentType.getInteger(context, | ||
+ | } | ||
- | This method is where all of your parsing will occur. Either this method will return the object based on the arguments provided in the command line or throw a CommandSyntaxException and parsing will fail. | + | private static int executeMultiply(int value, int value2, CommandContext<ServerCommandSource> context) { |
- | + | | |
- | Next you will store the current position of the cursor, this is so you can substring out only the specific argument. This will always be at the beginning of where your argument appears on the command line. | + | context.getSource().sendFeedback(() -> Text.literal("%s × %s = %s" |
- | + | | |
- | <code java [enable_line_numbers=" | + | } |
- | int argBeginning | + | |
- | if (!reader.canRead()) { | + | |
- | | + | |
} | } | ||
</ | </ | ||
+ | ===== A sub command ===== | ||
- | Now we grab the entire argument. Depending on your argument type, you may have a different criteria or be similar to some arguments where detecting a '' | + | To add a sub command, you register the first literal node of the command |
- | < | + | < |
- | while (reader.canRead() && reader.peek() != ' ') { // peek provides the character at the current cursor position. | + | dispatcher.register(literal(" |
- | reader.skip(); | + | |
- | } | + | |
</ | </ | ||
- | Then we will ask the StringReader what the current position of the cursor is an substring our argument out of the command line. | + | In order to have a sub command, one needs to append |
- | <code java [enable_line_numbers=" | + | This creates the command '' |
- | + | ||
- | Now finally we check if our argument is correct and parse the specific argument to our liking, and throwing an exception if the parsing fails. | + | |
<code java [enable_line_numbers=" | <code java [enable_line_numbers=" | ||
- | try { | + | dispatcher.register(literal(" |
- | | + | .then(literal(" |
- | | + | .executes(context -> { |
- | } catch (Exception ex) { | + | // For versions below 1.19, use '' |
- | // UUIDs can throw an exception when made by a string, so we catch the exception and repackage it into a CommandSyntaxException type. | + | // For versions below 1.20, use directly |
- | // Create with context tells Brigadier to supply some context to tell the user where the command failed at. | + | |
- | // Though normal create method could be used. | + | |
- | throw new SimpleCommandExceptionType(new LiteralText(ex.getMessage())).createWithContext(reader); | + | return 1; |
- | } | + | }) |
+ | ) | ||
+ | ); | ||
</ | </ | ||
- | The ArgumentType is done, however your client will refuse | + | Similar to arguments, sub command nodes can also be set optional. In the following case, both ''/ |
- | Within your ModInitializer (Not only client or server) you will add this so the client can recognize the argument when the command tree is sent. For more complex argument types, you may need to create your own ArgumentSerializer. | + | |
<code java [enable_line_numbers=" | <code java [enable_line_numbers=" | ||
- | ArgumentTypes.register(" | + | dispatcher.register(literal("foo") |
- | // The argument should be what will create the ArgumentType. | + | |
+ | context.getSource().sendFeedback(() -> Text.literal(" | ||
+ | | ||
+ | }) | ||
+ | | ||
+ | .executes(context -> { | ||
+ | context.getSource().sendFeedback(() -> Text.literal(" | ||
+ | return 1; | ||
+ | }) | ||
+ | ) | ||
+ | ); | ||
</ | </ | ||
+ | ====== Advanced concepts ====== | ||
- | And here is the whole ArgumentType: | + | Below are links to the articles about more complex concepts used in brigadier. |
- | <file java UUIDArgumentType.java [enable_line_numbers=" | + | ^ Page ^ Description |
+ | | [[command_exceptions | ||
+ | | [[command_suggestions|Suggestions]] | ||
+ | | [[command_redirects|Redirects]] | ||
+ | | [[command_argument_types|Custom Argument Types]] | ||
+ | | [[command_examples|Examples]] | Some example commands | | ||
- | import com.mojang.brigadier.StringReader; | + | ====== FAQ ====== |
- | import com.mojang.brigadier.arguments.ArgumentType; | + | |
- | import com.mojang.brigadier.context.CommandContext; | + | |
- | import com.mojang.brigadier.exceptions.CommandSyntaxException; | + | |
- | import com.mojang.brigadier.exceptions.SimpleCommandExceptionType; | + | |
- | import net.minecraft.text.LiteralText; | + | |
- | import net.minecraft.util.SystemUtil; | + | |
- | import java.util.ArrayList; | + | ===== Why does my code not compile ===== |
- | import java.util.Collection; | + | |
- | import java.util.UUID; | + | |
- | /** | + | There are several immediate possibilities |
- | * Represents an ArgumentType that will return a UUID. | + | |
- | */ | + | |
- | public class UUIDArgumentType implements ArgumentType< | + | |
- | // This method exists | + | |
- | public static UUIDArgumentType uuid() { | + | |
- | return new UUIDArgumentType(); | + | |
- | } | + | |
- | // This is also for convince and you could always just grab the argument from the CommandContext. | + | * **Catch or throw a CommandSyntaxException: |
- | public static <S> UUID getUuid(String name, CommandContext< | + | * **Issues with generics:** You may have an issue with generics once in a while. |
- | // Note that you should | + | * **Check '' |
- | // | + | * **'' |
- | return | + | |
- | } | + | |
- | private static final Collection< | + | ===== Can I register client side commands? ===== |
- | list.add(" | + | |
- | list.add(" | + | |
- | list.add(" | + | |
- | }); | + | |
- | @Override | + | Fabric has a '' |
- | public UUID parse(StringReader reader) throws CommandSyntaxException { | + | |
- | int argBeginning = reader.getCursor(); | + | |
- | if (!reader.canRead()) { | + | |
- | reader.skip(); | + | |
- | } | + | |
- | + | ||
- | // Now we check the contents of the argument till either we hit the end of the command line (When canRead becomes false) | + | |
- | // Otherwise we go till reach reach a space, which signifies the next argument | + | |
- | while (reader.canRead() && reader.peek() != ' ') { // peek provides the character at the current cursor position. | + | |
- | reader.skip(); | + | |
- | } | + | |
- | + | ||
- | // Now we substring the specific part we want to see using the starting cursor position and the ends where the next argument starts. | + | |
- | String uuidString = reader.getString().substring(argBeginning, | + | |
- | try { | + | |
- | UUID uuid = UUID.fromString(uuidString); | + | |
- | return uuid; // And we return our type, in this case the parser will consider this argument to have parsed properly and then move on. | + | |
- | } catch (Exception ex) { | + | |
- | // UUIDs can throw an exception when made by a string, so we catch the exception and repackage it into a CommandSyntaxException type. | + | |
- | // Create with context tells Brigadier to supply some context to tell the user where the command failed at. | + | |
- | // Though normal create method could be used. | + | |
- | throw new SimpleCommandExceptionType(new LiteralText(ex.getMessage())).createWithContext(reader); | + | |
- | } | + | |
- | } | + | |
- | + | ||
- | @Override | + | |
- | public Collection< | + | |
- | return EXAMPLES; | + | |
- | } | + | |
- | } | + | |
- | </ | + | |
- | ===== FAQ ===== | + | |
- | + | ||
- | === What else can I send feedback to the CommandSource? | + | |
- | + | ||
- | You can choose between Brigadier' | + | |
- | + | ||
- | === Why does my IDE complain saying that a method executed by my command needs to catch or throw a CommandSyntaxException === | + | |
- | + | ||
- | The solution to this is just to make the methods throw a CommandSyntaxException down the whole chain as the executes block handles the exceptions. | + | |
- | + | ||
- | === Can I register commands | + | |
- | + | ||
- | You can do this but it is not reccomended. You would get the instance of the CommandManager and add anything you wish to the CommandDispatcher within it. | + | |
- | + | ||
- | After that you will need to send the command tree to every player again using '' | + | |
- | + | ||
- | === Can I unregister commands | + | |
- | + | ||
- | You can also do this but it is very unstable and could cause unwanted side effects. Lets just say it involves a bunch of Reflection. | + | |
- | + | ||
- | Once again you will need to send the command tree to every player again using '' | + | |
- | + | ||
- | === Can I register | + | |
- | + | ||
- | Well Fabric currently doesn' | + | |
- | https:// | + | |
- | + | ||
- | If you only want the command to only be visible on the integrated server like ''/ | + | |
<code java> | <code java> | ||
- | dispatcher.register(literal(" | + | ClientCommandRegistrationCallback.EVENT.register((dispatcher, |
- | // The permission level 4 on integrated server is the equivalent of having cheats enabled. | + | .executes(context |
- | .requires(source | + | context.getSource().sendFeedback(Text.literal("The command is executed in the client!" |
+ | return 1; | ||
+ | } | ||
+ | | ||
</ | </ | ||
- | === I want to access X from my mod when a command | + | If you need to open a screen in the client |
- | This is going to require a way to statically access your mod with a '' | + | ===== Can I register commands |
- | <code java> | + | You can do this but it is not recommended. You would get the '' |
- | private static Type instance; | + | |
- | static { // Static option on class initalize for seperate API class for example | + | After that you need to send the command tree to every player again using '' |
- | | + | |
- | } | + | |
- | public void onInitalize() { // If within your mod initalizer | + | ===== Can I unregister commands in runtime? ===== |
- | | + | |
- | } | + | You can also do this, however it is much less stable than registering commands and could cause unwanted side effects. To keep things simple, you need to use reflection on brigadier and remove the nodes. After this, you need to send the command tree to every player again using '' |
- | public static Type getInstance() { | ||
- | return instance; | ||
- | } | ||
- | </ |
tutorial/commands.txt · Last modified: 2024/02/23 14:22 by allen1210