Package net.neoforged.neoforge.capabilities

Class BlockCapabilityCache<T,C>

java.lang.Object

net.neoforged.neoforge.capabilities.BlockCapabilityCache<T,C>

public final class BlockCapabilityCache<T,C>
extends Object

A cache for block capabilities, to be used to track capabilities at a specific position, with a specific context.

The cache is invalidated when the level is notified of a change via ILevelExtension.invalidateCapabilities(BlockPos).

Instances are automatically cleared by the garbage collector when they are no longer in use.

Field Summary

Fields

Modifier and Type	Field	Description
private T	cachedCap
private boolean	cacheValid	true if notifications received by the cache will be forwarded to listener.
private boolean	canQuery
private final BlockCapability<T,C>	capability
private final C	context
private final ServerLevel	level
private final ICapabilityInvalidationListener	listener
private final BlockPos	pos

Constructor Summary

Constructors

Modifier	Constructor	Description
private	BlockCapabilityCache(BlockCapability<T,C> capability, ServerLevel level, BlockPos pos, C context, BooleanSupplier isValid, Runnable invalidationListener)

Method Summary

Modifier and Type	Method	Description
C	context()
static <T, C> BlockCapabilityCache<T,C>	create(BlockCapability<T,C> capability, ServerLevel level, BlockPos pos, C context)	Creates a new cache instance and registers it to the level.
static <T, C> BlockCapabilityCache<T,C>	create(BlockCapability<T,C> capability, ServerLevel level, BlockPos pos, C context, BooleanSupplier isValid, Runnable invalidationListener)	Creates a new cache instance with an invalidation listener, and registers it to the level.
T	getCapability()	Gets the capability instance, or null if the capability is not present.
ServerLevel	level()
BlockPos	pos()

Methods inherited from class java.lang.Object

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

Field Details

capability

private final BlockCapability<T,C> capability

level

private final ServerLevel level

pos

private final BlockPos pos

context

private final C context

cacheValid

private boolean cacheValid

true if notifications received by the cache will be forwarded to listener. By default and after each invalidation, this is set to false. Calling getCapability() sets it to true.

cachedCap

@Nullable
private T cachedCap

canQuery

private boolean canQuery

listener

private final ICapabilityInvalidationListener listener

Constructor Details

BlockCapabilityCache

private BlockCapabilityCache(BlockCapability<T,C> capability,
 ServerLevel level,
 BlockPos pos,
 C context,
 BooleanSupplier isValid,
 Runnable invalidationListener)

Method Details

create

public static <T,
C> BlockCapabilityCache<T,C> create(BlockCapability<T,C> capability,
 ServerLevel level,
 BlockPos pos,
 C context)

Creates a new cache instance and registers it to the level.

Parameters:

capability - the capability

level - the level

pos - the position

context - extra context for the query

create

public static <T,
C> BlockCapabilityCache<T,C> create(BlockCapability<T,C> capability,
 ServerLevel level,
 BlockPos pos,
 C context,
 BooleanSupplier isValid,
 Runnable invalidationListener)

Creates a new cache instance with an invalidation listener, and registers it to the level.

A few details regarding the system:

• Calling getCapability() from the invalidation listener is not supported, as the block being invalidated might not be ready to be queried again yet. If you receive an invalidation notification, you should wait for some time (e.g. until your own tick) before checking getCapability() again.
• In general, do not perform any level access for the listener. The listener itself might be in a chunk that is being unloaded, for example.
• The listener does not receive notifications before getCapability() is called. After each invalidation, getCapability() must be called again to enable further notifications.

Parameters:

capability - the capability

level - the level

pos - the position

context - extra context for the query

isValid - a function to check if the listener still wants to receive notifications. A typical example would be () -> !this.isRemoved() for a block entity that should not receive invalidation notifications anymore once it is removed.

invalidationListener - the invalidation listener. Will be called whenever the capability of the cache might have changed.

level

public ServerLevel level()

pos

public BlockPos pos()

context

public C context()

getCapability

@Nullable
public T getCapability()

Gets the capability instance, or null if the capability is not present.

If the target position is not loaded, this method will return null.