com.facebook.buck.core.starlark.rule.attr

Interface PostCoercionTransform<AdditionalDataType,PostTransformType>

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 PostCoercionTransform<AdditionalDataType,PostTransformType>

Simple interface to take a coerced value for an Attribute on a build target utilizing information only known at analysis time.

This is not done by the type coercer and Attribute.getValue(com.facebook.buck.core.cell.nameresolver.CellNameResolver, ProjectFilesystem, ForwardRelativePath, TargetConfiguration, TargetConfiguration, Object) for two reasons. The ProjectFilesystem, ForwardRelativePath, TargetConfiguration, Object)} for two reasons. The first is that some information (like ProviderInfoCollection for dependencies) is not available until the analysis phase, rather than the parsing / coercion / configuration phases. Secondly is for speed. If we do not need to do a transformation on a given attribute, it's better to skip the function call.

Method Summary

Modifier and Type	Method and Description
PostTransformType	postCoercionTransform(Object coercedValue, AdditionalDataType additionalData) Transform a coerced attribute value for a specific rule in a way that utilizes deps.

Method Detail

postCoercionTransform

PostTransformType postCoercionTransform(Object coercedValue,
                                        AdditionalDataType additionalData)

Transform a coerced attribute value for a specific rule in a way that utilizes deps.

This is often done to transform attributes for a build target into something more useful to users in their impelementation functions. e.g. a list of dependencies that are represented as BuildTargets into a list of associated ProviderInfoCollections

Parameters:

coercedValue - the value that has been coerced by Attribute.getTypeCoercer()

additionalData - additional data that is used to perform the transformation of the coerced data.

Returns:

The value to now use that utilizes information in deps

Throws:

IllegalArgumentException - if coercedValue is not of the correct type or could otherwise not be transformed (e.g. a required dep is missing from deps).