akka.stream.OverflowStrategy.scala Maven / Gradle / Ivy
/**
* Copyright (C) 2009-2017 Lightbend Inc.
*/
package akka.stream
import OverflowStrategies._
/**
* Represents a strategy that decides how to deal with a buffer of time based stage
* that is full but is about to receive a new element.
*/
sealed abstract class DelayOverflowStrategy extends Serializable
final case class BufferOverflowException(msg: String) extends RuntimeException(msg)
/**
* Represents a strategy that decides how to deal with a buffer that is full but is
* about to receive a new element.
*/
sealed abstract class OverflowStrategy extends DelayOverflowStrategy
private[akka] object OverflowStrategies {
/**
* INTERNAL API
*/
private[akka] case object DropHead extends OverflowStrategy
/**
* INTERNAL API
*/
private[akka] case object DropTail extends OverflowStrategy
/**
* INTERNAL API
*/
private[akka] case object DropBuffer extends OverflowStrategy
/**
* INTERNAL API
*/
private[akka] case object DropNew extends OverflowStrategy
/**
* INTERNAL API
*/
private[akka] case object Backpressure extends OverflowStrategy
/**
* INTERNAL API
*/
private[akka] case object Fail extends OverflowStrategy
/**
* INTERNAL API
*/
private[akka] case object EmitEarly extends DelayOverflowStrategy
}
object OverflowStrategy {
/**
* If the buffer is full when a new element arrives, drops the oldest element from the buffer to make space for
* the new element.
*/
def dropHead: OverflowStrategy = DropHead
/**
* If the buffer is full when a new element arrives, drops the youngest element from the buffer to make space for
* the new element.
*/
def dropTail: OverflowStrategy = DropTail
/**
* If the buffer is full when a new element arrives, drops all the buffered elements to make space for the new element.
*/
def dropBuffer: OverflowStrategy = DropBuffer
/**
* If the buffer is full when a new element arrives, drops the new element.
*/
def dropNew: OverflowStrategy = DropNew
/**
* If the buffer is full when a new element is available this strategy backpressures the upstream publisher until
* space becomes available in the buffer.
*/
def backpressure: OverflowStrategy = Backpressure
/**
* If the buffer is full when a new element is available this strategy completes the stream with failure.
*/
def fail: OverflowStrategy = Fail
}
object DelayOverflowStrategy {
/**
* If the buffer is full when a new element is available this strategy send next element downstream without waiting
*/
def emitEarly: DelayOverflowStrategy = EmitEarly
/**
* If the buffer is full when a new element arrives, drops the oldest element from the buffer to make space for
* the new element.
*/
def dropHead: DelayOverflowStrategy = DropHead
/**
* If the buffer is full when a new element arrives, drops the youngest element from the buffer to make space for
* the new element.
*/
def dropTail: DelayOverflowStrategy = DropTail
/**
* If the buffer is full when a new element arrives, drops all the buffered elements to make space for the new element.
*/
def dropBuffer: DelayOverflowStrategy = DropBuffer
/**
* If the buffer is full when a new element arrives, drops the new element.
*/
def dropNew: DelayOverflowStrategy = DropNew
/**
* If the buffer is full when a new element is available this strategy backpressures the upstream publisher until
* space becomes available in the buffer.
*/
def backpressure: DelayOverflowStrategy = Backpressure
/**
* If the buffer is full when a new element is available this strategy completes the stream with failure.
*/
def fail: DelayOverflowStrategy = Fail
}