Package net.minecraftforge.event.entity.living

Class MobSpawnEvent.FinalizeSpawn

java.lang.Object

net.minecraftforge.eventbus.api.Event

net.minecraftforge.event.entity.EntityEvent

net.minecraftforge.event.entity.living.MobSpawnEvent

net.minecraftforge.event.entity.living.MobSpawnEvent.FinalizeSpawn

Enclosing class:

MobSpawnEvent

public static class MobSpawnEvent.FinalizeSpawn
extends MobSpawnEvent

This event is fired before Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) is called.
This allows mods to control mob initialization.
In vanilla code, this event is injected by a transformer and not via patch, so calls cannot be traced via call hierarchy (it is not source-visible).

Canceling this event will result in Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) not being called, and the returned value always being null, instead of propagating the SpawnGroupData.
The entity will still be spawned. If you want to prevent the spawn, use setSpawnCancelled(boolean), which will cause Forge to prevent the spawn.

This event is fired on MinecraftForge.EVENT_BUS, and is only fired on the logical server.

See Also:

• ForgeEventFactory.onFinalizeSpawn(net.minecraft.world.entity.Mob, net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag)

API Note:

Callers do not need to check if the entity's spawn was cancelled, as the spawn will be blocked by Forge.

Nested Class Summary

Nested classes/interfaces inherited from class net.minecraftforge.event.entity.living.MobSpawnEvent

MobSpawnEvent.AllowDespawn, MobSpawnEvent.FinalizeSpawn

Nested classes/interfaces inherited from class net.minecraftforge.event.entity.EntityEvent

EntityEvent.EnteringSection, EntityEvent.EntityConstructing, EntityEvent.Size

Nested classes/interfaces inherited from class net.minecraftforge.eventbus.api.Event

net.minecraftforge.eventbus.api.Event.HasResult, net.minecraftforge.eventbus.api.Event.Result

Field Summary

Fields

Modifier and Type	Field	Description
private DifficultyInstance	difficulty
private @Nullable SpawnGroupData	spawnData
private final @Nullable BaseSpawner	spawner
private @Nullable CompoundTag	spawnTag
private final MobSpawnType	spawnType

Constructor Summary

Constructors

Constructor	Description
FinalizeSpawn(Mob entity, ServerLevelAccessor level, double x, double y, double z, DifficultyInstance difficulty, MobSpawnType spawnType, @Nullable SpawnGroupData spawnData, @Nullable CompoundTag spawnTag, @Nullable BaseSpawner spawner)

Method Summary

Modifier and Type	Method	Description
DifficultyInstance	getDifficulty()	Retrieves the DifficultyInstance for the chunk where the mob is about to be spawned.
@Nullable SpawnGroupData	getSpawnData()	Retrieves the SpawnGroupData for this entity.
@Nullable BaseSpawner	getSpawner()	Retrieves the underlying BaseSpawner instance if this mob was created by a Mob Spawner of some form.
@Nullable CompoundTag	getSpawnTag()	This is the NBT data the entity was loaded from, if applicable.
MobSpawnType	getSpawnType()	Retrieves the type of mob spawn that happened (the event that caused the spawn).
boolean	isSpawnCancelled()	Returns the current spawn cancellation status, which can be changed via setSpawnCancelled(boolean).
void	setDifficulty(DifficultyInstance inst)	Sets the difficulty instance for this event, which will be propagated to Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) unless cancelled.
void	setSpawnCancelled(boolean cancel)	This method can be used to cancel the spawn of this mob.
void	setSpawnData(@Nullable SpawnGroupData data)	Sets the spawn data for this entity.
void	setSpawnTag(@Nullable CompoundTag tag)	Sets the spawn data for this event, which will be propagated to Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) unless cancelled.

Methods inherited from class net.minecraftforge.event.entity.living.MobSpawnEvent

getEntity, getLevel, getX, getY, getZ

Methods inherited from class net.minecraftforge.eventbus.api.Event

getListenerList, getPhase, getResult, hasResult, isCancelable, isCanceled, setCanceled, setPhase, setResult

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

spawnType

private final MobSpawnType spawnType

spawner

@Nullable
private final @Nullable BaseSpawner spawner

difficulty

private DifficultyInstance difficulty

spawnData

@Nullable
private @Nullable SpawnGroupData spawnData

spawnTag

@Nullable
private @Nullable CompoundTag spawnTag

Constructor Details

FinalizeSpawn

public FinalizeSpawn(Mob entity,
 ServerLevelAccessor level,
 double x,
 double y,
 double z,
 DifficultyInstance difficulty,
 MobSpawnType spawnType,
 @Nullable
 @Nullable SpawnGroupData spawnData,
 @Nullable
 @Nullable CompoundTag spawnTag,
 @Nullable
 @Nullable BaseSpawner spawner)

Method Details

getDifficulty

public DifficultyInstance getDifficulty()

Retrieves the DifficultyInstance for the chunk where the mob is about to be spawned.

Returns:

The local difficulty instance

setDifficulty

public void setDifficulty(DifficultyInstance inst)

Sets the difficulty instance for this event, which will be propagated to Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) unless cancelled. The difficulty instance controls how likely certain random effects are to occur, or if certain mob abilities are enabled.

Parameters:

inst - The new difficulty instance.

getSpawnType

public MobSpawnType getSpawnType()

Retrieves the type of mob spawn that happened (the event that caused the spawn). The enum names are self-explanatory.

Returns:

The mob spawn type.

See Also:

• MobSpawnType

getSpawnData

@Nullable
public @Nullable SpawnGroupData getSpawnData()

Retrieves the SpawnGroupData for this entity. When spawning mobs in a loop, this group data is used for the entire group and impacts future spawns. This is how entities like horses ensure that the whole group spawns as a single variant. How this is used varies on a per-entity basis.

Returns:

The spawn group data.

setSpawnData

public void setSpawnData(@Nullable
 @Nullable SpawnGroupData data)

Sets the spawn data for this entity. If this event is cancelled, this value is not used, since Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) will not be called.

Parameters:

data - The new spawn data

See Also:

• getSpawnData()

getSpawnTag

@Nullable
public @Nullable CompoundTag getSpawnTag()

This is the NBT data the entity was loaded from, if applicable. It is unknown if the entity has already been loaded from this data, or if it will be loaded later. Callers should not modify this data. If you need to change the data, you can create a copy, modify it, and set it via setSpawnTag(net.minecraft.nbt.CompoundTag)

Returns:

The spawn data this entity was or will be loaded from, if any.

setSpawnTag

public void setSpawnTag(@Nullable
 @Nullable CompoundTag tag)

Sets the spawn data for this event, which will be propagated to Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) unless cancelled. The only vanilla mob known to use this tag for anything in finalize is tropical fish for setting the variant when spawned via bucket.

Parameters:

tag - The new spawn tag

getSpawner

@Nullable
public @Nullable BaseSpawner getSpawner()

Retrieves the underlying BaseSpawner instance if this mob was created by a Mob Spawner of some form. This is always null unless getSpawnType() is MobSpawnType.SPAWNER, and may still be null even then.

Returns:

The BaseSpawner responsible for triggering the spawn, or null if none is available.

setSpawnCancelled

public void setSpawnCancelled(boolean cancel)

This method can be used to cancel the spawn of this mob.

This method must be used if you want to block the spawn, as canceling the event only blocks the call to Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag).

Note that if the spawn is cancelled, but the event is not, then Mob.finalizeSpawn(net.minecraft.world.level.ServerLevelAccessor, net.minecraft.world.DifficultyInstance, net.minecraft.world.entity.MobSpawnType, net.minecraft.world.entity.SpawnGroupData, net.minecraft.nbt.CompoundTag) will still be called, but the entity will not be spawned. Usually that has no side effects, but callers should be aware.

Parameters:

cancel - If the spawn should be cancelled (or not).

isSpawnCancelled

public boolean isSpawnCancelled()

Returns the current spawn cancellation status, which can be changed via setSpawnCancelled(boolean).

Returns:

If this mob's spawn is cancelled or not.

Implementation Note:

This is enforced in ForgeInternalHandler.builtinMobSpawnBlocker(net.minecraftforge.event.entity.EntityJoinLevelEvent) and a patch in WorldGenRegion#addEntity