Package org.geysermc.geyser.item.hashing

Interface EnumMapDispatchHasher<DistinctType,ValueType>

Type Parameters:

DistinctType - the distinct type used to indicate the implementation of a EnumMapDispatchHasher

ValueType - the abstract, base type to hash

All Known Implementing Classes:

ConsumeEffectType, NbtComponentType, ObjectContentsType

public interface EnumMapDispatchHasher<DistinctType,ValueType>

Utility interface with utility methods for creating MapBuilders for a scenario in which there is an abstract type A (EnumMapDispatchHasher), indicated by a typeKey of EnumMapDispatchHasher, and for each implementation of A, a MapBuilder exists, hashing an instance of the implementation. This interface builds on the MapBuilder.dispatch(String, MinecraftHasher, Function, Function) method to achieve this.

Essentially, implementations of this interface, when grouped together in e.g. an enum, function as a fancy named map from instances of A to their respective hashers.

A common way of implementing this is as follows:

1. Create an enum, implementing EnumMapDispatchHasher, with the enum as EnumMapDispatchHasher and the base type A as EnumMapDispatchHasher.
2. Add a clazz field to the enum, of type Class<? extends A>, and a mapBuilder field, of type MapBuilder<? extends A>.
   • The clazz field is used to recognise an implementation of A and find an instance of EnumMapDispatchHasher for a certain instance of an implementation of A.

     It is therefore important that the clazz field is unique for all constants in the enum.

   • The mapBuilder field is then used to hash that implementation of A.
   • You can use a typed constructor like this to ensure that the type of clazz is the same as mapBuilder, and to provide proper typing information for the mapBuilder:

     <T extends A> MyExampleEnum(Class<T> clazz, MapBuilder<T> builder)

     In which T is an implementation of A, and A is the base type to hash.

3. For each implementation of A, add a constant to that enum, specifying the clazz of that implementation, and a mapBuilder for it.

   The name of the constant will be used to encode the value of the typeKey, so be sure it is right and matches Java edition!

4. The methods of EnumMapDispatchHasher are to be implemented as follows:
   • distinction() returns this.
   • valueTypeClass() returns the clazz field.
   • mapBuilder() returns the mapBuilder field.
5. Finally, create the MapBuilder with the dispatch(Supplier) or the dispatch(String, Supplier) method, using MyExampleEnum::values as hashersSupplier.

Example implementations can be seen in ConsumeEffectType, NbtComponentType, and ObjectContentsType. If a MinecraftHasher is required instead of a MapBuilder, use MinecraftHasher.mapBuilder(MapBuilder) to wrap the MapBuilder into a hasher.

The implementation described above uses the enum itself as EnumMapDispatchHasher for A, and then uses dispatch(String, Supplier), which uses MinecraftHasher.fromEnum() to encode the enum constant for typeKey. This may not always be wanted behaviour, and this interface does allow using a different EnumMapDispatchHasher. In that case, the hasher for the EnumMapDispatchHasher has to be given, using the dispatch(MinecraftHasher, Supplier) or the dispatch(String, MinecraftHasher, Supplier) method.

See Also:

• dispatch(Supplier)
• dispatch(String, Supplier)
• dispatch(MinecraftHasher, Supplier)
• dispatch(String, MinecraftHasher, Supplier)

Method Summary

Modifier and Type	Method	Description
static <Value, HasherEnum extends Enum<HasherEnum> & EnumMapDispatchHasher<HasherEnum, Value>> MapBuilder<Value>	dispatch(String typeKey, Supplier<HasherEnum[]> hashersSupplier)	Delegates to dispatch(String, MinecraftHasher, Supplier), using the EnumMapDispatchHasher as Distinct type.
static <Distinct, Value, HasherEnum extends EnumMapDispatchHasher<Distinct, Value>> MapBuilder<Value>	dispatch(String distinctTypeKey, MinecraftHasher<Distinct> distinctHasher, Supplier<HasherEnum[]> hashersSupplier)	Creates a MapBuilder for an abstract type EnumMapDispatchHasher, using an array of implementations of EnumMapDispatchHasher, and the distinctTypeKey to indicate the EnumMapDispatchHasher type of an implementation of EnumMapDispatchHasher.
static <Value, HasherEnum extends Enum<HasherEnum> & EnumMapDispatchHasher<HasherEnum, Value>> MapBuilder<Value>	dispatch(Supplier<HasherEnum[]> hashersSupplier)	Delegates to dispatch(String, Supplier), uses "type" as typeKey.
static <Distinct, Value, HasherEnum extends EnumMapDispatchHasher<Distinct, Value>> MapBuilder<Value>	dispatch(MinecraftHasher<Distinct> distinctHasher, Supplier<HasherEnum[]> hashersSupplier)	Delegates to dispatch(String, MinecraftHasher, Supplier), using "type" as distinctTypeKey.
DistinctType	distinction()	Returns the EnumMapDispatchHasher of this implementation of EnumMapDispatchHasher.
MapBuilder<? extends ValueType>	mapBuilder()
Class<? extends ValueType>	valueTypeClass()

Method Details

distinction

DistinctType distinction()

Returns the EnumMapDispatchHasher of this implementation of EnumMapDispatchHasher.

Implementations must ensure that each EnumMapDispatchHasher is unique and only for one implementation of EnumMapDispatchHasher.

Returns:

the EnumMapDispatchHasher of this implementation of EnumMapDispatchHasher

valueTypeClass

Class<? extends ValueType> valueTypeClass()

Returns:

the Class of this implementation of EnumMapDispatchHasher

mapBuilder

MapBuilder<? extends ValueType> mapBuilder()

Returns:

the MapBuilder used to encode this implementation of EnumMapDispatchHasher

dispatch

static <Value,
HasherEnum extends Enum<HasherEnum> & EnumMapDispatchHasher<HasherEnum,
Value>>
MapBuilder<Value> dispatch(Supplier<HasherEnum[]> hashersSupplier)

Delegates to dispatch(String, Supplier), uses "type" as typeKey.

See Also:

• dispatch(String, Supplier)
• dispatch(String, MinecraftHasher, Supplier)

dispatch

static <Value,
HasherEnum extends Enum<HasherEnum> & EnumMapDispatchHasher<HasherEnum,
Value>>
MapBuilder<Value> dispatch(String typeKey,
 Supplier<HasherEnum[]> hashersSupplier)

Delegates to dispatch(String, MinecraftHasher, Supplier), using the EnumMapDispatchHasher as Distinct type.

Uses MinecraftHasher.fromEnum() as hasher for EnumMapDispatchHasher/the Distinct type, so be sure that the enum constants match what you want to appear in the map!

See Also:

• dispatch(String, MinecraftHasher, Supplier)

dispatch

static <Distinct,
Value,
HasherEnum extends EnumMapDispatchHasher<Distinct,
Value>>
MapBuilder<Value> dispatch(MinecraftHasher<Distinct> distinctHasher,
 Supplier<HasherEnum[]> hashersSupplier)

Delegates to dispatch(String, MinecraftHasher, Supplier), using "type" as distinctTypeKey.

See Also:

• dispatch(String, MinecraftHasher, Supplier)

dispatch

static <Distinct,
Value,
HasherEnum extends EnumMapDispatchHasher<Distinct,
Value>>
MapBuilder<Value> dispatch(String distinctTypeKey,
 MinecraftHasher<Distinct> distinctHasher,
 Supplier<HasherEnum[]> hashersSupplier)

Creates a MapBuilder for an abstract type EnumMapDispatchHasher, using an array of implementations of EnumMapDispatchHasher, and the distinctTypeKey to indicate the EnumMapDispatchHasher type of an implementation of EnumMapDispatchHasher.

Type Parameters:

Distinct - the distinct type used to indicate an implementation of EnumMapDispatchHasher

Value - the abstract, base type to create a MapBuilder for

Parameters:

distinctTypeKey - the key in the map used to indicate the EnumMapDispatchHasher type

distinctHasher - the hasher used to hash the EnumMapDispatchHasher type

hashersSupplier - a supplier returning the array of EnumMapDispatchHasher implementations, one for each implementation of EnumMapDispatchHasher

Returns:

the created MapBuilder