Boolean Monitor

BooleanMonitor.scala

import java.util.concurrent.TimeUnit

import scala.concurrent.duration.Duration

import com.google.common.util.concurrent.Monitor

class BooleanMonitor(monitor: Monitor = new Monitor())(check: => Boolean) {
  private val guard = new Monitor.Guard(monitor) { override def isSatisfied = check }

  def whenSatisfied[U](timeout: Duration = Duration.Inf)(f: => U): U = {
    if (timeout.isFinite()) {
      monitor.enterWhen(guard, timeout.toMillis, TimeUnit.MILLISECONDS)
    }
    else {
      monitor.enterWhen(guard)
    }
    try {
      f
    }
    finally {
      monitor.leave()
    }
  }
}