Scala-ARM for class members?

Question

I'm very new to Scala, so please excuse my basic question.

I'm trying to get Scala-Arm to manage the release of a class member, but having trouble with scoping.

Although the following code compiles, it fails with

java.lang.NoSuchMethodError: resource.ManagedResource.reflect()Ljava/lang/Object;

on the reflect call. So it seems the the managed_file is being released immediately.

For local variables I have used the for (managed_file <- managed(...)) syntax but I can't see what to do here.

Suggestions anyone?

class Writer(outputPath: String){

  val managed_file = managed(new FileOutputStream(new File(outputPath)))

  def write(something : SomeClass) {
    var bos = new ByteArrayOutputStream
    var dos = new DataOutputStream(bos)

    try {
      dos.write(Marshal.dump(something))
      bos.writeTo(managed_file.reflect)
    } 
    finally {
      dos.close
      bos.close
    }
  }
}

score 0 · Accepted Answer · answered Aug 01 '14 at 08:28

0

NoSuchMethodError is a compilation/runtime difference error. You compile succesfully against Scal ARM, but this one is not found (or at least not found in same version) during runtime.

answered Aug 01 '14 at 08:28

cchantep

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Thanks for your help. I've searched my system and I have only a single Scala ARM JAR. I've updated my classpath to explicitly reference it but I get still the same behavior. Wouldn't a run-time resolution problem mean I should get the same error using the local variable `for(managedFile <- managed(...))` syntax? – puppet Aug 04 '14 at 12:50
NoSuchMethodError can't be a syntax, which would be detected by compiler. Have you tried your code in REPL (launching console from SBT CLI)? – cchantep Aug 04 '14 at 14:13
Thanks again. I just tried running it from REPL and got the same result. This wasn't via SBT though, I'm not sure how to do that, I'll look into it tomorrow. – puppet Aug 05 '14 at 18:40
In SBT REPL, try `classOf[resource.ManagedResource].getMethod("reflect", Array[Class]())` – cchantep Aug 05 '14 at 19:23
And in SBT try `show dependencyClasspath` to check from which JAR Scala-ARM is loaded. – cchantep Aug 05 '14 at 21:37
Hi again, I can see from `show dependencyClasspath` there's something funny going on with the resolution of Scala-ARM. I'll be able to resolve it from here with that info, so I'm going to mark this as resolved. Thanks. – puppet Aug 07 '14 at 19:22

Scala-ARM for class members?

1 Answers1