s_mach.datadiff.impl.SetDataDiffImpl.scala Maven / Gradle / Ivy

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/*
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       ;it1i ,,,:::;;;::1tti      s_mach.datadiff
         .t1i .,::;;; ;1tt        Copyright (c) 2014 S-Mach, Inc.
         Lft11ii;::;ii1tfL:       Author: [email protected]
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*/
package s_mach.datadiff.impl

import s_mach.datadiff.{SetPatch, DataDiff}

import scala.collection.generic.CanBuildFrom

class SetDataDiffImpl[A](implicit
  cbf: CanBuildFrom[Nothing, A, Set[A]]
) extends DataDiff[Set[A],SetPatch[A]] {

  override val noChange : SetPatch[A] = SetPatch.noChange

  override def calcDiff(oldValue: Set[A], newValue: Set[A]): Patch = {
    val remove = oldValue -- newValue
    if(remove.isEmpty && oldValue.size == newValue.size) {
      noChange
    } else {
      val add = newValue -- oldValue
      SetPatch(add, remove)
    }
  }

  override def applyPatch(value: Set[A], patch: Patch): Set[A] = {
    if(patch != noChange) {
      val builder = cbf()
      value.iterator.filterNot(patch.remove.contains).foreach(builder.+=)
      builder ++= patch.add
      builder.result()
    } else {
      value
    }
  }

}