Interface MergePolicy

public interface MergePolicy

Decides whether a storage holding one variant of a type may accept another variant of the same type, and what the stored variant becomes (ARCHITECTURE.md §9.2). Different types never merge, whatever the policy says.

Implementations must be deterministic and must not use floating point.

Field Summary

Fields

Modifier and Type	Field	Description
static final MergePolicy	STRICT	Only equal variants merge.

Method Summary

Modifier and Type	Method	Description
boolean	canMerge(@NotNull ResourceVariant existing, @NotNull ResourceVariant incoming)
@NotNull ResourceVariant	merge(@NotNull ResourceVariant existing, long existingAmount, @NotNull ResourceVariant incoming, long incomingAmount)	Only called when canMerge(ResourceVariant, ResourceVariant) returned true.
static @NotNull MergePolicy	weightedAverage(@NotNull ResourceComponentType<Long> component)	Merges variants that differ only in component, replacing it by the amount-weighted average (rounded down).

Field Details

STRICT

static final MergePolicy STRICT

Only equal variants merge. The default for every category.

Method Details

canMerge

boolean canMerge(@NotNull
 @NotNull ResourceVariant existing,
 @NotNull
 @NotNull ResourceVariant incoming)

merge

@NotNull
@NotNull ResourceVariant merge(@NotNull
 @NotNull ResourceVariant existing,
 long existingAmount,
 @NotNull
 @NotNull ResourceVariant incoming,
 long incomingAmount)

Only called when canMerge(ResourceVariant, ResourceVariant) returned true.

Returns:

the variant stored after adding incomingAmount of incoming to existingAmount of existing

weightedAverage

@NotNull
static @NotNull MergePolicy weightedAverage(@NotNull
 @NotNull ResourceComponentType<Long> component)

Merges variants that differ only in component, replacing it by the amount-weighted average (rounded down). Example: mixing 100 mB of steam at 400 K into 300 mB at 300 K gives 400 mB at 325 K.