monifu.reactive.internals.operators.debug.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.operators
import java.io.PrintStream
import monifu.concurrent.Cancelable
import monifu.reactive.Ack.Cancel
import monifu.reactive.{Ack, Observer, Observable}
import monifu.reactive.internals._
import scala.concurrent.Future
import scala.util.control.NonFatal
private[reactive] object debug {
/**
* Implementation for [[Observable.dump]].
*/
def dump[T](source: Observable[T], prefix: String, out: PrintStream): Observable[T] =
Observable.create[T] { subscriber =>
implicit val s = subscriber.scheduler
val observer = subscriber.observer
source.onSubscribe(new Observer[T] {
private[this] var pos = 0
private[this] val downstreamActive = Cancelable {
pos += 1; out.println(s"$pos: $prefix canceled")
}
def onNext(elem: T): Future[Ack] = {
// Protects calls to user code from within the operator
var streamError = true
try {
out.println(s"$pos: $prefix-->$elem")
streamError = false
pos += 1
observer.onNext(elem)
.ifCanceledDoCancel(downstreamActive)
}
catch {
case NonFatal(ex) =>
if (streamError) { observer.onError(ex); Cancel } else
Future.failed(ex)
}
}
def onError(ex: Throwable) = {
try {
out.println(s"$pos: $prefix-->$ex")
pos += 1
}
catch {
case NonFatal(_) =>
() // ignore
}
observer.onError(ex)
}
def onComplete() = {
try {
out.println(s"$pos: $prefix completed")
pos += 1
}
catch {
case NonFatal(_) =>
() // ignore
}
observer.onComplete()
}
})
}
}