Differences

This shows you the differences between two versions of the page.

--- tutorial:mixin_injects [2022/03/08 18:56] – Added interface inection section. salvopelux
+++ tutorial:mixin_injects [2022/08/05 19:19] (current) – Added signed to integer types clomclem
@@ Line 5: / Line 5: @@
 <code java>
-@Inject(method = "", at = @At("INJECTION POINT REFERENCE"))
+@Inject(method = "METHOD NAME OR SIGNATURE", at = @At("INJECTION POINT REFERENCE"))
 private void injectMethod(METHOD ARGS, CallbackInfo info) {
@@ Line 28: / Line 28: @@
 | D | double | double-precision floating-point value |
 | F | float | single-precision floating-point value |
-| I | int | integer |
+| I | int | signed integer |
-| J | long | long integer |
+| J | long | signed long integer |
 | L//ClassName//; | reference | an instance of //ClassName// |
 | S | short | signed short |
@@ Line 35: / Line 35: @@
 | [ | reference | one array dimension |
-A method descriptor is comprised of the method name, followed by a set of parentheses containing the input types, followed by the output type. A method defined in Java as ''Object m(int i, double[] d, Thread t)'' would have the method descriptor ''m(I[DLjava/lang/Thread;)Ljava/lang/Object;''.
+A method descriptor is comprised of the method name, followed by a set of parentheses containing the parameter types, followed by the return type. A method defined in Java as ''Object m(int i, double[] d, Thread t)'' would have the method descriptor ''m(I[DLjava/lang/Thread;)Ljava/lang/Object;''.
-Generics' types are left out, as Generics don't exist on runtime. So ''Pair<Integer, ? extends Task<? super VillagerEntity>‍>'' would become ''Lcom/mojang/datafixers/util/Pair''.
+In the case that the return type is void, you need to use V (Void Descriptor Type) as the type (for example, ''void foo(String bar)'' would become ''foo(Ljava/lang/String;)V'').
-//@Inject// methods always have a void return type. The method name does not matter; using something that describes what the inject does is best. The target method's arguments are placed first in the method's header, followed by a ''CallbackInfo'' object. If the target method has a return type (T), ''CallbackInfoReturnable<T>'' is used instead of ''CallbackInfo''.
+Generics' types are left out, as generics don't exist on runtime. So ''Pair<Integer, ? extends Task<? super VillagerEntity>‍>'' would become ''Lcom/mojang/datafixers/util/Pair''.
+''@Inject'' methods always have a void return type. The method name does not matter and neither does the access modifier; using something that describes what the inject does is best. The target method's arguments are placed first in the method's header, followed by a ''CallbackInfo'' object. If the target method has a return type (T), ''CallbackInfoReturnable<T>'' is used instead of ''CallbackInfo''.
 === Returning & Cancelling from Inject ===
@@ Line 67: / Line 69: @@
 For more information on this particular example, view its usage in the [[https://github.com/FabricMC/fabric-example-mod/blob/master/src/main/java/net/fabricmc/example/mixin/ExampleMixin.java|Fabric Example Mod repo]].
-====== Inject an interface ======
-This is a new tecnique introduced by Loom 0.11 to add methods into a specific existing class.
-More specifically, you can create an Interface, and then inject this interface into the class.
-As result the target class will acquire all the methods of the interface, as if it always had them.
-Interface injection is a compile time only feature, this means that a Mixin should also be used to implement the interface into the target class.
-This is particulatly useful for libraries, with this you can add new methods to existing classes and use them without the need of casting or reimplementing the interface every time.
-Let's explain better with an example:
-The scope of this example is to add the following method into FlowableFluid to get the sound of the bucket when emptied.
-This, normally, is not possible because FlowableFluid does not has a similar method.
-<code java [enable_line_numbers="false"]>
-Optional<SoundEvent> getBucketEmptySound()
-</code>
-To add the method into the class, first of all you need to create an interface with it:
-<code java [enable_line_numbers="false"]>
-package net.fabricmc.example;
-public interface BucketEmptySoundGetter {
-	Optional<SoundEvent> getBucketEmptySound();
-}
-</code>
-Now you need to implement this interface into FlowableFluid with a mixin implementing the interface:
-<code java [enable_line_numbers="false"]>
-@Mixin(FlowableFluid.class)
-public class MixinFlowableFluid implements BucketEmptySoundGetter {
-	@Override
-	public Optional<SoundEvent> getBucketEmptySound() {
-		return Optional.of(((FlowableFluid) (Object) this).isIn(FluidTags.LAVA) ? SoundEvents.ITEM_BUCKET_EMPTY_LAVA : SoundEvents.ITEM_BUCKET_EMPTY);
-	}
-}
-</code>
-Lastly you need to inject the interface into FabricFluid.
-The following snippet can be added to your fabric.mod.json file to add one or more interfaces to the net/minecraft/fluid/FlowableFluid class.
-<code json [enable_line_numbers="false"]>
-{
-	"custom": {
-		"loom:injected_interfaces": {
-			"net/minecraft/class_3609": ["net/fabricmc/example/BucketEmptySoundGetter"]
-		}
-	}
-}
-</code>
-Now you can use the new method:
-<code java [enable_line_numbers="false"]>
-Optional<SoundEvent> sound = mytestfluid.getBucketEmptySound();
-</code>
-You could also override this method in classes extending FlowableFluid to implement custom behaviours.