51 lines
1.1 KiB
Scala
51 lines
1.1 KiB
Scala
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/**
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* Copyright (C) 2009 Scalable Solutions.
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*/
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package com.scalablesolutions.akka.kernel
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/**
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* Reference that can hold either a typed value or an exception.
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*
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* Usage:
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* <pre>
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* scala> ErrRef(1)
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* res0: ErrRef[Int] = ErrRef@a96606
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*
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* scala> res0()
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* res1: Int = 1
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*
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* scala> res0() = 3
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*
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* scala> res0()
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* res3: Int = 3
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*
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* scala> res0() = { println("Hello world"); 3}
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* Hello world
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*
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* scala> res0()
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* res5: Int = 3
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*
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* scala> res0() = error("Lets see what happens here...")
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*
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* scala> res0()
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* java.lang.RuntimeException: Lets see what happens here...
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* at ErrRef.apply(RefExcept.scala:11)
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* at .<init>(<console>:6)
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* at .<clinit>(<console>)
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* at Re...
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* </pre>
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*/
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class ErrRef[S](s: S){
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private[this] var contents: Either[Throwable, S] = Right(s)
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def update(value: => S) = contents = try { Right(value) } catch { case (e : Throwable) => Left(e) }
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def apply() = contents match {
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case Right(s) => s
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case Left(e) => throw e.fillInStackTrace
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}
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override def toString(): String = "ErrRef[" + contents + "]"
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}
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object ErrRef {
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def apply[S](s: S) = new ErrRef(s)
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}
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