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--- tutorial:command_suggestions [2023/02/20 05:44] – solidblock
+++ tutorial:command_suggestions [2023/11/18 12:06] (current) – solidblock
@@ Line 3: / Line 3: @@
 ====== Command Suggestions ======
-Brigadier allows specification of custom suggestions for arguments. In Minecraft, these suggestions are sent to the client as a user is typing out the command.
+Brigadier allows specification of custom suggestions for arguments. In Minecraft, these suggestions are sent to the client as a user is typing out the command. Besides, some argument types can have their default suggestion providers calculated directly in client, which is not focused in this article.
 ===== Suggestion Providers =====
-A ''SuggestionProvider'' is used to make a list of suggestions that will be sent to the client. A suggestion provider is a functional interface that takes a ''CommandContext'' and a ''SuggestionBuilder'' and returns some ''Suggestions''. The ''SuggestionProvider'' returns a [[https://docs.oracle.com/en/java/javase/15/docs/api/java.base/java/util/concurrent/CompletableFuture.html|CompletableFuture]] as the suggestions may not be available immediately.
+A ''SuggestionProvider'' is used to make a list of suggestions that will be sent to the client. A suggestion provider is a functional interface that takes a ''CommandContext'' and a ''SuggestionBuilder'' and returns some ''Suggestions''. The ''SuggestionProvider'' returns a ''CompletableFuture'' as the suggestions may not be available immediately.
 Suggestions can be contextual since a suggestion provider gives you access to the current command context.
@@ Line 16: / Line 16: @@
 <code java [enable_line_numbers="true", highlight_lines_extra="4"]>
-class AttributeSuggestionProvider implements SuggestionProvider<ServerCommandSource> {
+public class AttributeSuggestionProvider implements SuggestionProvider<ServerCommandSource> {
     @Override
     public CompletableFuture<Suggestions> getSuggestions(CommandContext<ServerCommandSource> context, SuggestionsBuilder builder) throws CommandSyntaxException {
@@ Line 28: / Line 28: @@
 <code java [enable_line_numbers="true"]>
-class AttributeSuggestionProvider implements SuggestionProvider<ServerCommandSource> {
+public class AttributeSuggestionProvider implements SuggestionProvider<ServerCommandSource> {
     @Override
     public CompletableFuture<Suggestions> getSuggestions(CommandContext<ServerCommandSource> context, SuggestionsBuilder builder) {
@@ Line 36: / Line 36: @@
         if (!DefaultAttributeContainer.hasDefinitionFor(entityType)) {
-            // TODO: Fail
+            return Suggestions.empty()
         }
         DefaultAttributeContainer attributeContainer = DefaultAttributeRegistry.get(entityType);
         // You will need mixin to get the 'instances map'. Lets assume we can just access it for the sake of the tutorial
-        for (EntityAttribute attribute : attributeContainer.instances().keySet()) {
+        for (EntityAttribute attribute : attributeContainer.instances.keySet()) {
             Identifier attributeId = Registries.ATTRIBUTE.getId(attribute);
-            if (attributeId != null) {
+            if (attributeId != null && CommandSource.shouldSuggest(builder.getRemaining(), attributeId.toString())) {
             ...
 </code>
+The check of ''CommandSource.shouldSuggest'' is intended to suggest only results that match the inputed part, which is ''builder.getRemaining()'', which is the part between the beginning of the argument and the cursor.
 In order to have a suggestion appear on the client, you must add the suggestion to the builder. This can be done through one of the ''suggest'' methods. Some of these handle numbers, and a few support showing a tooltip.
 <code java [enable_line_numbers="true", highlight_lines_extra="4"]>
-for (EntityAttribute attribute : attributeContainer.instances().keySet()) {
+        for (EntityAttribute attribute : attributeContainer.instances.keySet()) {
-    Identifier attributeId = Registries.ATTRIBUTE.getId(attribute);
+            Identifier attributeId = Registries.ATTRIBUTE.getId(attribute);
-    if (attributeId != null) {
+            if (attributeId != null && CommandSource.shouldSuggest(builder.getRemaining(), attributeId.toString())) {
-       builder.suggest(attributeId.toString());
+               builder.suggest(attributeId.toString());
-    }
+            }
-}
+        }
 </code>
@@ Line 63: / Line 65: @@
 <code java [enable_line_numbers="true"]>
-return builder.buildFuture();
+        return builder.buildFuture();
 </code>
@@ Line 69: / Line 71: @@
 <code java [enable_line_numbers="true"]>
-class AttributeSuggestionProvider implements SuggestionProvider<ServerCommandSource> {
+public class AttributeSuggestionProvider implements SuggestionProvider<ServerCommandSource> {
     @Override
     public CompletableFuture<Suggestions> getSuggestions(CommandContext<ServerCommandSource> context, SuggestionsBuilder builder) {
@@ Line 76: / Line 78: @@
         if (!DefaultAttributeContainer.hasDefinitionFor(entityType)) {
-            // TODO: Fail
+            return Suggestions.empty()
         }
         DefaultAttributeContainer attributeContainer = DefaultAttributeRegistry.get(entityType);
         // You will need mixin to get the 'instances map'. Lets assume we can just access it for the sake of the tutorial
-        for (EntityAttribute attribute : attributeContainer.instances().keySet()) {
+        for (EntityAttribute attribute : attributeContainer.instances.keySet()) {
             Identifier attributeId = Registries.ATTRIBUTE.getId(attribute);
-            if (attributeId != null) {
+            if (attributeId != null && CommandSource.shouldSuggest(builder.getRemaining(), attributeId.toString())) {
                 builder.suggest(attributeId.toString());
             }
@@ Line 116: / Line 118: @@
 ===== Utilities in CommandSource =====
-''CommandSource'' contains a few utility methods to help remove boilerplate when making the suggestions.
+''CommandSource'' contains a few utility methods to help remove boilerplate when making the suggestions. Many of the utility methods involve returning completed suggestions from a ''Stream'' or ''Set'' of Identifiers, positions or matching strings.
-Many of the utility methods involve returning completed suggestions from a ''Stream'' or ''Set'' of Identifiers, positions or matching strings.
+In the example above, we can simplify it to:
+<code java>
+        DefaultAttributeContainer attributeContainer = DefaultAttributeRegistry.get(entityType);
+        // You will need mixin to get the 'instances map'. Lets assume we can just access it for the sake of the tutorial
+        return CommandSource.suggestMatching(Iterables.transform(attributeContainer.instances.keySet(), Identifier::toString), builder);
+        // you can also use stream:
+        return CommandSource.suggestMatching(attributeContainer.instances.keySet().stream().map(Identifier::toString), builder);
+</code>
+===== Builder offsets =====
+Most cases the suggestions appear from the beginning of the argument, such as the example above. However, sometimes suggestions appear in the middle of the argument. For example, in a block state argument, you input ''oak_stairs['', and then suggestions should be property names of the block (''facing'', ''waterlogged'', ...). The suggestion appears after the left square bracket.
+In this case, you should use ''builder.createOffset(offset)'', where ''offset'' is the position of the new suggestion builder.
 ===== Other command tutorials =====
-[[tutorial:commands#advanced_concepts|Click here]] to view the other command tutorials.
+For other command tutorials, see the sidebar.