com.ossuminc.riddl.utils.AdjustableClock.scala Maven / Gradle / Ivy

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Various utilities used throughout riddl libraries

There is a newer version: 0.52.1

/*
 * Copyright 2019 Ossum, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

package com.ossuminc.riddl.utils

import java.time.*

/** An implementation of java.time.Clock which only moves through time via calls
  * to `updateInstant`. This allows fine-grained, side-effect-free deterministic
  * control over the progression of system time, which is useful for testing
  * purposes.
  */
final class AdjustableClock(
  private var inst: Instant,
  zone: ZoneId = ZoneId.of("UTC"))
    extends Clock {

  override def getZone: ZoneId = zone

  override def withZone(zone: ZoneId): Clock =
    new AdjustableClock(instant(), zone)
  override def instant(): Instant = inst

  /** Updates the current time of this clock to the result of applying `f` to
    * the current time
    */
  def updateInstant(f: Instant => Instant): this.type = {
    this.inst = f(this.inst)
    this
  }
}