nthportal / reservoir   0.4.0

Apache License 2.0 GitHub

Reservoir sampling implementation with akka-streams support

Scala versions: 2.13


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Reservoir sampling implementation with Akka Streams support

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Scala 2.13

libraryDependencies += "lgbt.princess" %% "reservoir-core"        % "0.4.0"  // the core library supporting synchronous reservoir sampling
libraryDependencies += "lgbt.princess" %% "reservoir-akka-stream" % "0.4.0"  // the library for akka-stream operators
libraryDependencies += "lgbt.princess" %% "reservoir"             % "0.4.0"  // all parts of the library


Reservoir Sampler

import lgbt.princess.reservoir.Sampler

final case class User(id: String, displayName: String)

val sampler = Sampler[User, String](maxSampleSize = 100)(_.id)
val sampleIds = sampler.result()

val distinctSampler = Sampler.distinct[User, String](maxSampleSize = 100)(_.id)
val distinctSampleIds = distinctSampler.result()

Akka Stream Operator

import akka.stream.scaladsl.{Keep, Sink}
import lgbt.princess.reservoir.akkasupport.Sample

final case class User(id: String, displayName: String)

val (users1, sampleIds) = onlineUsers()
  .viaMat(Sample[User, String](maxSampleSize = 100)(_.id))(Keep.right)
val (users2, distinctSampleIds) = onlineUsers()
  .viaMat(Sample.distinct[User, String](maxSampleSize = 100)(_.id))(Keep.right)