Package org.geysermc.geyser.item.hashing

Interface MinecraftHasher<Type>

Type Parameters:

Type - the type this hasher hashes.

All Known Subinterfaces:

RegistryHasher<DirectType>

All Known Implementing Classes:

RegistryHasher.RegistryHasherWithDirectHasher

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface MinecraftHasher<Type>

Encodes an object into a HashCode using a MinecraftHashEncoder.

Hashers have been implemented for common types, such as all Java primitives, units (encodes an empty map), NBT maps and lists, Vector3i positions, Key resource locations and #-prefixed tags, UUIDs, and more types. Furthermore, in RegistryHasher more hashers can be found for more specific for Minecraft types, and ComponentHasher.COMPONENT hashes Components.

Most hashers are not created by implementing them directly, rather, they are built on top of other hashers, using various methods to manipulate and map them. Here are some commonly used ones:

• list() creates a hasher that hashes a list of the objects.
• cast(Function) and registryCast(BiFunction) create a new hasher that delegates to this hasher with a converter function.
• filterable() creates a hasher that hashes a Filterable instance of the object.

On top of these there are more methods, as well as static helper methods in this class, to create hashers. One worth pointing out is mapBuilder(MapBuilder), which hashes an object into a map-like structure. Read the documentation there, on MapBuilder, and on MapHasher on how to use it.

As of right now, hashers are used to create hash codes for data components, which Minecraft requires to be sent in inventory transactions. You'll find all the hashers for data components in DataComponentHashers. In the future, hashers may be used elsewhere as well. If necessary, this system can even be refactored to write to different data structures, such as NBT or JSON files, as well.

When creating new hashers, please be sure to put them in the proper place:

• Hashers that hash very generic types, or types that are used broadly across Minecraft (like key, UUID, game profile, etc.) belong here in MinecraftHasher.
• Hashers that hash more specific types, are more complicated, or depend on a hasher in RegistryHasher, belong in RegistryHasher.
• Hashers that hash components, and are used nowhere else, belong in DataComponentHashers.

Field Summary

Fields

Modifier and Type	Field	Description
static final MinecraftHasher<Boolean>	BOOL
static final MinecraftHasher<Byte>	BYTE
static final MinecraftHasher<byte[]>	BYTE_ARRAY
static final MinecraftHasher<Double>	DOUBLE
static final MinecraftHasher<Integer>	DYE_COLOR
static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.entity.EquipmentSlot>	EQUIPMENT_SLOT
static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.item.component.ItemAttributeModifiers.EquipmentSlotGroup>	EQUIPMENT_SLOT_GROUP
static final MinecraftHasher<Float>	FLOAT
static final MinecraftHasher<org.geysermc.mcprotocollib.auth.GameProfile.Property>	GAME_PROFILE_PROPERTY
static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.entity.metadata.GlobalPos>	GLOBAL_POS
static final MinecraftHasher<Integer>	INT
static final MinecraftHasher<int[]>	INT_ARRAY
static final MinecraftHasher<net.kyori.adventure.key.Key>	KEY
static final MinecraftHasher<net.kyori.adventure.key.Key>	KEY_REMOVAL
static final MinecraftHasher<Long>	LONG
static final MinecraftHasher<long[]>	LONG_ARRAY
static final MinecraftHasher<org.cloudburstmc.nbt.NbtList<?>>	NBT_LIST
static final MinecraftHasher<org.cloudburstmc.nbt.NbtMap>	NBT_MAP
static final MinecraftHasher<org.cloudburstmc.math.vector.Vector3i>	POS
static final MinecraftHasher<Integer>	RARITY
static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.entity.player.ResolvableProfile>	RESOLVABLE_PROFILE
static final MinecraftHasher<Short>	SHORT
static final MinecraftHasher<String>	STRING
static final MinecraftHasher<net.kyori.adventure.key.Key>	TAG
static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.item.component.Unit>	UNIT
static final MinecraftHasher<UUID>	UUID

Method Summary

Modifier and Type	Method	Description
default <Casted> MinecraftHasher<Casted>	cast(Function<Casted,Type> converter)	"Casts" this hasher to another hash a different object, with a converter method.
default <Dispatched> MinecraftHasher<Dispatched>	dispatch(String typeKey, Function<Dispatched,Type> typeExtractor, Function<Type,MapBuilder<Dispatched>> mapDispatch)	Creates a hasher that dispatches a MinecraftHasher from a MinecraftHasher using typeExtractor, puts this in the typeKey key in a map, and uses a MapBuilder provided by mapDispatch to build the rest of the map.
default <Dispatched> MinecraftHasher<Dispatched>	dispatch(Function<Dispatched,Type> typeExtractor, Function<Type,MapBuilder<Dispatched>> hashDispatch)	Delegates to dispatch(String, Function, Function), uses "type" as the typeKey.
static <Type> MinecraftHasher<Type>	dispatch(Function<Type,MinecraftHasher<Type>> hashDispatch)	Creates a hasher that dispatches a MinecraftHasher from a MinecraftHasher, and then uses that hasher to encode MinecraftHasher.
static <Type, First, Second> MinecraftHasher<Type>	either(MinecraftHasher<First> firstHasher, Function<Type,First> firstExtractor, MinecraftHasher<Second> secondHasher, Function<Type,Second> secondExtractor)	Creates a hasher that hashes MinecraftHasher using either firstHasher to hash MinecraftHasher (obtained using firstExtractor), or uses secondHasher to hash MinecraftHasher (obtained via secondExtractor).
default MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.item.component.Filterable<Type>>	filterable()	Creates a hasher that wraps the MinecraftHasher in a Filterable.
static <EnumConstant extends Enum<EnumConstant>> MinecraftHasher<EnumConstant>	fromEnum()	Uses Enum.name() (lowercased) as toName function in fromEnum(Function).
static <EnumConstant extends Enum<EnumConstant>> MinecraftHasher<EnumConstant>	fromEnum(Function<EnumConstant,String> toName)	Creates a hasher for MinecraftHashers that uses toName to turn a MinecraftHasher into a string, which it then hashes.
static <EnumConstant extends Enum<EnumConstant>> MinecraftHasher<Integer>	fromIdEnum(EnumConstant[] values)	Uses Enum.name() (lowercased) as toName function in fromIdEnum(Enum[], Function).
static <EnumConstant extends Enum<EnumConstant>> MinecraftHasher<Integer>	fromIdEnum(EnumConstant[] values, Function<EnumConstant,String> toName)	Creates a hasher that looks up an int in the array of MinecraftHashers, and uses toName to turn the constant into a string, which it then hashes.
com.google.common.hash.HashCode	hash(Type value, MinecraftHashEncoder encoder)
static <Type> MinecraftHasher<Type>	lazyInitialize(Supplier<MinecraftHasher<Type>> hasher)	Lazily-initialises the given hasher using Suppliers.memoize(com.google.common.base.Supplier).
default MinecraftHasher<List<Type>>	list()	Creates a hasher that hashes a list of objects this hasher hashes.
static <K, V> MinecraftHasher<Map<K,V>>	map(MinecraftHasher<K> keyHasher, MinecraftHasher<V> valueHasher)	Creates a hasher that uses mapSet(MinecraftHasher, MinecraftHasher) to hash MinecraftHasher keys and MinecraftHasher values into a map, using the keyHasher and valueHasher respectively.
static <Type> MinecraftHasher<Type>	mapBuilder(MapBuilder<Type> builder)	Creates a hasher that uses a MapBuilder, which uses a MapHasher to hash a MinecraftHasher into a map.
static <Type> MinecraftHasher<Collection<Type>>	mapSet(MinecraftHasher<Type> keyHasher, MinecraftHasher<Type> valueHasher)	Creates a hasher that hashes a set of MinecraftHasher entries into a map of keys and values, using keyHasher and valueHasher respectively.
default <Casted> MinecraftHasher<Casted>	registryCast(BiFunction<JavaRegistryProvider,Casted,Type> converter)	Like cast(Function), but has access to JavaRegistryProvider.
static <Type> MinecraftHasher<Type>	unit()	Creates a hasher that always encodes into an empty map.

Field Details

UNIT

static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.item.component.Unit> UNIT

BYTE

static final MinecraftHasher<Byte> BYTE

SHORT

static final MinecraftHasher<Short> SHORT

INT

static final MinecraftHasher<Integer> INT

LONG

static final MinecraftHasher<Long> LONG

FLOAT

static final MinecraftHasher<Float> FLOAT

DOUBLE

static final MinecraftHasher<Double> DOUBLE

STRING

static final MinecraftHasher<String> STRING

BOOL

static final MinecraftHasher<Boolean> BOOL

BYTE_ARRAY

static final MinecraftHasher<byte[]> BYTE_ARRAY

INT_ARRAY

static final MinecraftHasher<int[]> INT_ARRAY

LONG_ARRAY

static final MinecraftHasher<long[]> LONG_ARRAY

NBT_MAP

static final MinecraftHasher<org.cloudburstmc.nbt.NbtMap> NBT_MAP

NBT_LIST

static final MinecraftHasher<org.cloudburstmc.nbt.NbtList<?>> NBT_LIST

POS

static final MinecraftHasher<org.cloudburstmc.math.vector.Vector3i> POS

KEY

static final MinecraftHasher<net.kyori.adventure.key.Key> KEY

TAG

static final MinecraftHasher<net.kyori.adventure.key.Key> TAG

KEY_REMOVAL

static final MinecraftHasher<net.kyori.adventure.key.Key> KEY_REMOVAL

UUID

static final MinecraftHasher<UUID> UUID

GAME_PROFILE_PROPERTY

static final MinecraftHasher<org.geysermc.mcprotocollib.auth.GameProfile.Property> GAME_PROFILE_PROPERTY

RESOLVABLE_PROFILE

static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.entity.player.ResolvableProfile> RESOLVABLE_PROFILE

RARITY

static final MinecraftHasher<Integer> RARITY

DYE_COLOR

static final MinecraftHasher<Integer> DYE_COLOR

EQUIPMENT_SLOT

static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.entity.EquipmentSlot> EQUIPMENT_SLOT

EQUIPMENT_SLOT_GROUP

static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.item.component.ItemAttributeModifiers.EquipmentSlotGroup> EQUIPMENT_SLOT_GROUP

GLOBAL_POS

static final MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.entity.metadata.GlobalPos> GLOBAL_POS

Method Details

hash

com.google.common.hash.HashCode hash(Type value,
 MinecraftHashEncoder encoder)

list

default MinecraftHasher<List<Type>> list()

Creates a hasher that hashes a list of objects this hasher hashes.

cast

default <Casted> MinecraftHasher<Casted> cast(Function<Casted,Type> converter)

"Casts" this hasher to another hash a different object, with a converter method. The returned hasher takes a MinecraftHasher, converts it to a MinecraftHasher using the converter, and then hashes it.

If a JavaRegistryProvider object is needed for conversion, use registryCast(BiFunction).

Type Parameters:

Casted - the type of the new hasher.

Parameters:

converter - the converter function that converts a MinecraftHasher into a MinecraftHasher.

See Also:

• registryCast(BiFunction)

registryCast

default <Casted> MinecraftHasher<Casted> registryCast(BiFunction<JavaRegistryProvider,Casted,Type> converter)

Like cast(Function), but has access to JavaRegistryProvider.

Type Parameters:

Casted - the type of the new hasher.

Parameters:

converter - the converter function.

See Also:

• cast(Function)

dispatch

default <Dispatched> MinecraftHasher<Dispatched> dispatch(Function<Dispatched,Type> typeExtractor,
 Function<Type,MapBuilder<Dispatched>> hashDispatch)

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

See Also:

• dispatch(String, Function, Function)
• MapBuilder.dispatch(MinecraftHasher, Function, Function)
• MapBuilder.dispatch(String, MinecraftHasher, Function, Function)

dispatch

default <Dispatched> MinecraftHasher<Dispatched> dispatch(String typeKey,
 Function<Dispatched,Type> typeExtractor,
 Function<Type,MapBuilder<Dispatched>> mapDispatch)

Creates a hasher that dispatches a MinecraftHasher from a MinecraftHasher using typeExtractor, puts this in the typeKey key in a map, and uses a MapBuilder provided by mapDispatch to build the rest of the map.

This can be used to create hashers that hash an abstract type or interface into a map with different keys depending on the type.

Internally this simply delegates to and wraps MapBuilder.dispatch(String, MinecraftHasher, Function, Function) in mapBuilder(MapBuilder), using this as typeHasher.

Type Parameters:

Dispatched - the type of the new hasher.

Parameters:

typeKey - the key to store the MinecraftHasher in.

typeExtractor - the function that extracts a MinecraftHasher from a MinecraftHasher.

mapDispatch - the function that provides a MapBuilder based on a MinecraftHasher.

See Also:

• MapBuilder.dispatch(String, MinecraftHasher, Function, Function)

filterable

default MinecraftHasher<org.geysermc.mcprotocollib.protocol.data.game.item.component.Filterable<Type>> filterable()

Creates a hasher that wraps the MinecraftHasher in a Filterable.

unit

static <Type> MinecraftHasher<Type> unit()

Creates a hasher that always encodes into an empty map.

lazyInitialize

static <Type> MinecraftHasher<Type> lazyInitialize(Supplier<MinecraftHasher<Type>> hasher)

Lazily-initialises the given hasher using Suppliers.memoize(com.google.common.base.Supplier).

fromIdEnum

static <EnumConstant extends Enum<EnumConstant>>
MinecraftHasher<Integer> fromIdEnum(EnumConstant[] values)

Uses Enum.name() (lowercased) as toName function in fromIdEnum(Enum[], Function).

Please be aware that you are using literal enum constants as string values here, meaning that if there is a typo in a constant, or a constant changes name, things may break. Use cautiously.

Type Parameters:

EnumConstant - the enum.

Parameters:

values - the array of MinecraftHashers.

See Also:

• fromIdEnum(Enum[], Function)

fromIdEnum

static <EnumConstant extends Enum<EnumConstant>>
MinecraftHasher<Integer> fromIdEnum(EnumConstant[] values,
 Function<EnumConstant,String> toName)

Creates a hasher that looks up an int in the array of MinecraftHashers, and uses toName to turn the constant into a string, which it then hashes.

Type Parameters:

EnumConstant - the enum.

Parameters:

values - the array of MinecraftHashers.

toName - the function that turns a MinecraftHasher into a string.

See Also:

• fromIdEnum(Enum[])

fromEnum

static <EnumConstant extends Enum<EnumConstant>>
MinecraftHasher<EnumConstant> fromEnum()

Uses Enum.name() (lowercased) as toName function in fromEnum(Function).

Please be aware that you are using literal enum constants as string values here, meaning that if there is a typo in a constant, or a constant changes name, things may break. Use cautiously.

Type Parameters:

EnumConstant - the enum.

See Also:

• fromEnum(Function)

fromEnum

static <EnumConstant extends Enum<EnumConstant>>
MinecraftHasher<EnumConstant> fromEnum(Function<EnumConstant,String> toName)

Creates a hasher for MinecraftHashers that uses toName to turn a MinecraftHasher into a string, which it then hashes.

Type Parameters:

EnumConstant - the enum.

Parameters:

toName - the function that turns a MinecraftHasher into a string.

See Also:

• fromEnum()

mapBuilder

static <Type> MinecraftHasher<Type> mapBuilder(MapBuilder<Type> builder)

Creates a hasher that uses a MapBuilder, which uses a MapHasher to hash a MinecraftHasher into a map.

Type Parameters:

Type - the type to hash.

Parameters:

builder - the builder that creates a map from a MinecraftHasher.

map

static <K,
V> MinecraftHasher<Map<K,V>> map(MinecraftHasher<K> keyHasher,
 MinecraftHasher<V> valueHasher)

Creates a hasher that uses mapSet(MinecraftHasher, MinecraftHasher) to hash MinecraftHasher keys and MinecraftHasher values into a map, using the keyHasher and valueHasher respectively.

Type Parameters:

K - the key type.

V - the value type.

Parameters:

keyHasher - the hasher that hashes objects of type MinecraftHasher.

valueHasher - the hasher that hashes objects of type MinecraftHasher.

See Also:

• mapSet(MinecraftHasher, MinecraftHasher)

mapSet

static <Type> MinecraftHasher<Collection<Type>> mapSet(MinecraftHasher<Type> keyHasher,
 MinecraftHasher<Type> valueHasher)

Creates a hasher that hashes a set of MinecraftHasher entries into a map of keys and values, using keyHasher and valueHasher respectively.

Note that the key hasher is usually expected to hash into a string, but this is not necessarily a requirement. It may be once different encoders are used to encode to NBT or JSON, but this is not the case yet.

Type Parameters:

Type - the entry type.

Parameters:

keyHasher - the hasher that hashes a MinecraftHasher into a key to be used in the map.

valueHasher - the hasher that hashes a MinecraftHasher into a value to be used in the map.

See Also:

• map(MinecraftHasher, MinecraftHasher)

either

static <Type,
First,
Second> MinecraftHasher<Type> either(MinecraftHasher<First> firstHasher,
 Function<Type,First> firstExtractor,
 MinecraftHasher<Second> secondHasher,
 Function<Type,Second> secondExtractor)

Creates a hasher that hashes MinecraftHasher using either firstHasher to hash MinecraftHasher (obtained using firstExtractor), or uses secondHasher to hash MinecraftHasher (obtained via secondExtractor).

Specifically, the hasher first tries to use firstExtractor to obtain a MinecraftHasher from MinecraftHasher. If this returns a not-null value, firstHasher is used to hash the value.

If the returned value is null, then secondExtractor is used to obtain a MinecraftHasher from MinecraftHasher. This must never be null. secondHasher is then used to hash the value.

Note: secondExtractor must never return null if firstExtractor does!

Type Parameters:

Type - the type to hash.

First - the first either type to hash.

Second - the second either type to hash.

Parameters:

firstHasher - the hasher used to hash MinecraftHasher.

firstExtractor - the function used to obtain a MinecraftHasher from a MinecraftHasher.

secondHasher - the hasher used to hash MinecraftHasher.

secondExtractor - the function used to obtain a MinecraftHasher from a MinecraftHasher.

dispatch

static <Type> MinecraftHasher<Type> dispatch(Function<Type,MinecraftHasher<Type>> hashDispatch)

Creates a hasher that dispatches a MinecraftHasher from a MinecraftHasher, and then uses that hasher to encode MinecraftHasher.

Type Parameters:

Type - the type to hash.

Parameters:

hashDispatch - the function that returns a MinecraftHasher from a MinecraftHasher.