On Fri, 06 Nov 2015 14:39:29 +0100, Paul Sandoz <paul.san...@oracle.com>
wrote:
On 6 Nov 2015, at 14:19, Fabrizio Giudici
<fabrizio.giud...@tidalwave.it> wrote:
I logged an issue:
https://bugs.openjdk.java.net/browse/JDK-8141608
<https://bugs.openjdk.java.net/browse/JDK-8141608>
Thanks to Remi and Paul for the complete explanation. Concerning
JDK-8141608, I lile Peter Levart's comment about making a specific
Collector.
There is a problem with that approach. At the moment the Collector does
not get to control whether the stream is executed in parallel or
sequentially.
Sure, I understand. I think it would be ok if the Collector has as a
pre-requisite that it can't be used with a parallel Stream. I assume that
if the stream is not parallel, the runtime won't ever try to execute the
Collector in parallel... right? That's what I see from the tests I've
executed so far.
I've tried to write such a FileCollector, with a check that throws an
exception if the accumulator Supplier function is called more than once,
with code such as:
private final AtomicBoolean parallelChecker = new AtomicBoolean();
@Override
public Supplier<PrintWriter> supplier()
{
return this::oneShotPrintWriterSupplier;
}
private PrintWriter oneShotPrintWriterSupplier()
{
if (parallelChecker.getAndSet(true))
{
fail();
}
return pw;
}
It seems to properly detect when it's called with a parallel Stream. Do
you think that it's safe enough?
Thanks.
--
Fabrizio Giudici - Java Architect @ Tidalwave s.a.s.
"We make Java work. Everywhere."
http://tidalwave.it/fabrizio/blog - fabrizio.giud...@tidalwave.it
