errors using JDK 7 on OS X

[Jon Brisbin]

I'm on OS X with the OpenJDK 1.7 port. I'm trying to run this simple test class and I'm getting an IllegalArgumentException in NIO:

scala> HawtDispatchTest.main(Array())
java.lang.IllegalArgumentException
    at java.nio.channels.spi.AbstractSelectableChannel.register(AbstractSelectableChannel.java:196)
    at java.nio.channels.SelectableChannel.register(SelectableChannel.java:277)
    at org.fusesource.hawtdispatch.internal.NioDispatchSource$2.run(NioDispatchSource.java:190)
    at org.fusesource.hawtdispatch.internal.pool.SimpleThread.run(SimpleThread.java:60)

Exception: java.lang.NullPointerException thrown from the UncaughtExceptionHandler in thread "hawtdispatch-DEFAULT-2"
java.lang.InterruptedException
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:996)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1303)
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:236)
    at HawtDispatchTest$.main(HawtDispatchTest.scala:68)
    at .<init>(<console>:8)
    at .<clinit>(<console>)
    at .<init>(<console>:11)
    at .<clinit>(<console>)
    at $print(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:704)
    at scala.tools.nsc.interpreter.IMain$Request$$anonfun$14.apply(IMain.scala:920)
    at scala.tools.nsc.interpreter.Line$$anonfun$1.apply$mcV$sp(Line.scala:43)
    at scala.tools.nsc.io.package$$anon$2.run(package.scala:25)
    at java.lang.Thread.run(Thread.java:722)

Here's the test class:

object HawtDispatchTest {

  def main(args: Array[String]) {
    val latch = new CountDownLatch(1)
    val channel = ServerSocketChannel.open()
    channel.socket().bind(new InetSocketAddress(3080))
    channel.configureBlocking(false)

    val queue = createQueue("test")
    val acceptSrc = createSource(channel, SelectionKey.OP_ACCEPT, queue)
    acceptSrc.setEventHandler(new Runnable {
      def run() {
        val socket = channel.accept()
        socket.configureBlocking(false)
        val buff = ByteBuffer.allocateDirect(16 * 1024)
        val req = createQueue("req")
        val readSrc = createSource(channel, SelectionKey.OP_READ, req)
        val writeSrc = createSource(channel, SelectionKey.OP_WRITE, req)

        readSrc.onCancel(() => writeSrc.cancel())
        writeSrc.onCancel(() => channel.close())

        readSrc.setEventHandler(new Runnable {
          def run() {
            if (socket.read(buff) == -1) {
              socket.close()
              readSrc.cancel()
            } else {
              buff.flip()
              if (buff.remaining() > 0) {
                println("got buffer: " + buff.toString)
                readSrc.suspend()
                writeSrc.resume()
              } else {
                buff.clear()
              }
            }
          }
        })

        writeSrc.setEventHandler(new Runnable {
          def run() {
            val buff = ByteBuffer.allocateDirect(12)
            buff.put("Hello World!".getBytes)
            buff.flip()
            socket.write(buff)
            writeSrc.suspend()
            readSrc.resume()
            latch.countDown()
          }
        })

        readSrc.resume()
      }
    })
    acceptSrc.resume()

    latch.await()
    channel.close()
  }

}

When I hit CTL-C to kill this test, my CPU usage spiked to 100%. I thought it was because of the continuations. But I don't think that's actually it. I think there's something else going on. I only noticed this after starting to play with HawtDispatch.

Thanks!

Jon Brisbin
http//jbrisbin.com

[Jon Brisbin]

BTW- I know there's an error in the test class. I typoed the variable name. The createSource() calls for READ and WRITE should pass "socket" not "channel". cut-and-paste error from the online example...

But I still can't figure out where the 100% CPU spike is coming from. I can't trigger it all the time, either. But I've only seen it so far when trying to run test classes from sbt.

Thanks!

Jon Brisbin
http//jbrisbin.com

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