the-algorithm/product-mixer/component-library/src/main/scala/com/twitter/product_mixer/component_library/filter/FeatureFilter.scala
twitter-team ef4c5eb65e Twitter Recommendation Algorithm
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2023-03-31 17:36:31 -05:00

64 lines
2.3 KiB
Scala

package com.twitter.product_mixer.component_library.filter
import com.twitter.product_mixer.core.feature.Feature
import com.twitter.product_mixer.core.functional_component.filter.Filter
import com.twitter.product_mixer.core.functional_component.filter.FilterResult
import com.twitter.product_mixer.core.model.common.CandidateWithFeatures
import com.twitter.product_mixer.core.model.common.UniversalNoun
import com.twitter.product_mixer.core.model.common.identifier.FilterIdentifier
import com.twitter.product_mixer.core.pipeline.PipelineQuery
import com.twitter.stitch.Stitch
object FeatureFilter {
/**
* Builds a Filter using the Feature name as the FilterIdentifier
*
* @see [[FeatureFilter.fromFeature(identifier, feature)]]
*/
def fromFeature[Candidate <: UniversalNoun[Any]](
feature: Feature[Candidate, Boolean]
): Filter[PipelineQuery, Candidate] =
FeatureFilter.fromFeature(FilterIdentifier(feature.toString), feature)
/**
* Builds a Filter that keeps candidates when the provided Boolean Feature is present and True.
* If the Feature is missing or False, the candidate is removed.
*
* {{{
* Filter.fromFeature(
* FilterIdentifier("SomeFilter"),
* feature = SomeFeature
* )
* }}}
*
* @param identifier A FilterIdentifier for the new filter
* @param feature A feature of [Candidate, Boolean] type used to determine whether Candidates will be kept
* when this feature is present and true otherwise they will be removed.
*/
def fromFeature[Candidate <: UniversalNoun[Any]](
identifier: FilterIdentifier,
feature: Feature[Candidate, Boolean]
): Filter[PipelineQuery, Candidate] = {
val i = identifier
new Filter[PipelineQuery, Candidate] {
override val identifier: FilterIdentifier = i
override def apply(
query: PipelineQuery,
candidates: Seq[CandidateWithFeatures[Candidate]]
): Stitch[FilterResult[Candidate]] = {
val (keptCandidates, removedCandidates) = candidates.partition { filterCandidate =>
filterCandidate.features.getOrElse(feature, false)
}
Stitch.value(
FilterResult(
kept = keptCandidates.map(_.candidate),
removed = removedCandidates.map(_.candidate)))
}
}
}
}