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• GCounterImpl.scala

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io.cloudstate.javasupport.impl.crdt.GCounterImpl.scala Maven / Gradle / Ivy

package io.cloudstate.javasupport.impl.crdt

import io.cloudstate.javasupport.crdt.GCounter
import io.cloudstate.protocol.crdt.{CrdtDelta, CrdtState, GCounterDelta, GCounterState}

private[crdt] final class GCounterImpl extends InternalCrdt with GCounter {
  override final val name = "GCounter"
  private var value: Long = 0
  private var deltaValue: Long = 0

  override def getValue: Long = value

  override def increment(by: Long): Long = {
    if (by < 0) {
      throw new IllegalArgumentException("Cannot increment a GCounter by a negative amount.")
    }
    deltaValue += by
    value += by
    value
  }

  override def hasDelta: Boolean = deltaValue != 0

  override def delta: Option[CrdtDelta.Delta] =
    if (hasDelta) {
      Some(CrdtDelta.Delta.Gcounter(GCounterDelta(deltaValue)))
    } else None

  override def resetDelta(): Unit = deltaValue = 0

  override def state: CrdtState.State = CrdtState.State.Gcounter(GCounterState(value))

  override val applyDelta = {
    case CrdtDelta.Delta.Gcounter(GCounterDelta(increment)) =>
      value += increment
  }

  override val applyState = {
    case CrdtState.State.Gcounter(GCounterState(value)) =>
      this.value = value
  }

  override def toString = s"GCounter($value)"
}