monifu.reactive.internals.operators.onError.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 monifu.concurrent.Scheduler
import monifu.reactive.{Observer, Observable}
import scala.util.control.NonFatal
private[reactive] object onError {
/**
* Implementation for [[Observable.onErrorRecoverWith]].
*/
def recoverWith[T](source: Observable[T], pf: PartialFunction[Throwable, Observable[T]]) =
Observable.create[T] { subscriber =>
implicit val s = subscriber.scheduler
val o = subscriber.observer
source.onSubscribe(new Observer[T] {
def onNext(elem: T) =
o.onNext(elem)
def onError(ex: Throwable) = {
// protecting user level code
var streamError = true
try {
if (pf.isDefinedAt(ex)) {
val fallbackTo = pf(ex)
// need asynchronous execution to avoid a synchronous loop
// blowing out the call stack
s.execute(fallbackTo.onSubscribe(o))
}
else {
// we can't protect the onError call and if it throws
// the behavior should be undefined
streamError = false
o.onError(ex)
}
}
catch {
case NonFatal(err) if streamError =>
// streaming the immediate exception
try o.onError(err) finally {
// logging the original exception
s.reportFailure(ex)
}
}
}
def onComplete() =
o.onComplete()
})
}
/**
* Implementation for [[Observable.onErrorFallbackTo]].
*/
def fallbackTo[T](source: Observable[T], other: => Observable[T]) =
Observable.create[T] { subscriber =>
implicit val s = subscriber.scheduler
val o = subscriber.observer
source.onSubscribe(new Observer[T] {
def onNext(elem: T) =
o.onNext(elem)
def onError(ex: Throwable) = {
try {
val fallback = other
// need asynchronous execution to avoid a synchronous loop
// blowing out the call stack
s.execute(fallback.onSubscribe(o))
}
catch {
case NonFatal(err) =>
// streaming the immediate exception
try o.onError(err) finally {
// logging the original exception
s.reportFailure(ex)
}
}
}
def onComplete() =
o.onComplete()
})
}
/**
* Implementation for [[Observable.onErrorRetry]].
*/
def retryCounted[T](source: Observable[T], maxRetries: Long) = {
// helper to subscribe in a loop when onError happens
def subscribe(o: Observer[T], retryIdx: Long)(implicit s: Scheduler): Unit =
source.onSubscribe(new Observer[T] {
def onNext(elem: T) = o.onNext(elem)
def onComplete() = o.onComplete()
def onError(ex: Throwable) = {
if (retryIdx < maxRetries) {
// need asynchronous execution to avoid a synchronous loop
// blowing out the call stack
s.execute(subscribe(o, retryIdx+1))
}
else {
o.onError(ex)
}
}
})
Observable.create[T] { s =>
subscribe(s.observer, 0)(s.scheduler)
}
}
/**
* Implementation for [[Observable.onErrorRetryUnlimited]].
*/
def retryUnlimited[T](source: Observable[T]): Observable[T] = {
// helper to subscribe in a loop when onError happens
def subscribe(o: Observer[T])(implicit s: Scheduler): Unit =
source.onSubscribe(new Observer[T] {
def onNext(elem: T) = o.onNext(elem)
def onComplete() = o.onComplete()
def onError(ex: Throwable) = {
// need asynchronous execution to avoid a synchronous loop
// blowing out the call stack
s.execute(subscribe(o))
}
})
Observable.create[T] { s =>
subscribe(s.observer)(s.scheduler)
}
}
/**
* Implementation for [[Observable.onErrorRetryIf]].
*/
def retryIf[T](source: Observable[T], p: Throwable => Boolean) = {
// helper to subscribe in a loop when onError happens
def subscribe(o: Observer[T])(implicit s: Scheduler): Unit =
source.onSubscribe(new Observer[T] {
def onNext(elem: T) = o.onNext(elem)
def onComplete() = o.onComplete()
def onError(ex: Throwable) = {
// protecting against user level code
try {
val shouldRetry = p(ex)
// need asynchronous execution to avoid a synchronous loop
// blowing out the call stack
if (shouldRetry)
s.execute(subscribe(o))
else
o.onError(ex)
}
catch {
case NonFatal(err) =>
// exception is getting lost, so try logging it
s.reportFailure(ex)
// reporting user code exception, which
// is always worse if it happens
o.onError(err)
}
}
})
Observable.create[T] { s =>
subscribe(s.observer)(s.scheduler)
}
}
}