monifu.reactive.internals.builders.range.scala Maven / Gradle / Ivy
/*
* Copyright (c) 2014-2015 by its authors. Some rights reserved.
* See the project homepage at: http://www.monifu.org
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package monifu.reactive.internals.builders
import monifu.reactive.Ack.Continue
import monifu.reactive.Observable
import scala.annotation.tailrec
private[reactive] object range {
/**
* Creates an Observable that emits items in the given range.
*
* 
*
* @param from the range start
* @param until the range end
* @param step increment step, either positive or negative
*/
def apply(from: Long, until: Long, step: Long = 1): Observable[Long] = {
require(step != 0, "step must be a number different from zero")
Observable.create { subscriber =>
implicit val s = subscriber.scheduler
val o = subscriber.observer
def scheduleLoop(from: Long, until: Long, step: Long): Unit =
s.execute(new Runnable {
private[this] def isInRange(x: Long): Boolean = {
(step > 0 && x < until) || (step < 0 && x > until)
}
def reschedule(from: Long, until: Long, step: Long): Unit =
fastLoop(from, until, step)
@tailrec
def fastLoop(from: Long, until: Long, step: Long): Unit =
if (isInRange(from))
o.onNext(from) match {
case sync if sync.isCompleted =>
sync.value.get match {
case Continue.IsSuccess =>
fastLoop(from + step, until, step)
case _ =>
() // do nothing else
}
case async =>
async.onComplete {
case Continue.IsSuccess =>
reschedule(from + step, until, step)
case _ =>
() // do nothing else
}
}
else
o.onComplete()
def run(): Unit = {
fastLoop(from, until, step)
}
})
scheduleLoop(from, until, step)
}
}
}