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From: Jon Olson <olson@mmsi.com>
To: "Jochen Hoenicke" <Jochen.Hoenicke@Informatik.Uni-Oldenburg.DE>,
	Per Bothner <per@bothner.com>
Cc: java-discuss@sourceware.cygnus.com, classpath@gnu.org
Subject: Re: Proposal for CNI/JNI problems
Date: Sat, 01 Apr 2000 00:00:00 -0000	[thread overview]
Message-ID: <00011208053500.10598@toontown.mmsi.com> (raw)
In-Reply-To: <14460.37463.273837.406646@celan.Informatik.Uni-Oldenburg.DE>

On Wed, 12 Jan 2000, Jochen Hoenicke wrote:

>Another point is how to put pointers to native structures into a
>classfile.  Sun didn't solve it well.  If I understand the code in
>japhar's java/util/zip correctly sun used an int field to store the
>pointer and later changed it to long to support 64bit architectures.
>libgcj declares natives fields as "gnu.gcj.RawData", but this is not
>portable to other jvms, where the garbage collector doesn't know that
>this class is special.  My solution was to put the structure into a
>java byte array, which imposes a little overhead, but should be
>portable (and you get it freed automatically).
>
>  Jochen

Interesting idea, putting the native peer class into a byte array.
Seems like kind of a hack, but I guess it solves the problem.
Sun's solution of using a long to store a pointer is a real kludge.

My solution was to store an `int' as the peer and to make any
Java class which require a native peer a subclass of this Peer
class:

public class Peer
{
  protected int _peer;
  public Peer(int peer)	{ _peer = peer; }
  public native void destroy();
  protected void finalize() {
    destroy();
  }
}

Native code stores peer objects in a C++ Vector and manages
recovering space when finalized in destroy().

-- 
Jon Olson, Modular Mining Systems
	   3289 E. Hemisphere Loop
	   Tucson, AZ 85706
INTERNET:  olson@mmsi.com
PHONE:     (520)746-9127
FAX:       (520)889-5790

  reply	other threads:[~2000-04-01  0:00 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-04-01  0:00 Paul Fisher
2000-04-01  0:00 ` Per Bothner
2000-04-01  0:00   ` Paul Fisher
2000-04-01  0:00     ` Per Bothner
2000-04-01  0:00     ` Aaron M. Renn
2000-04-01  0:00       ` Stuart Ballard
2000-04-01  0:00         ` Chris Blizzard
2000-04-01  0:00           ` Chris Blizzard
2000-04-01  0:00   ` Jochen Hoenicke
2000-04-01  0:00     ` Jon Olson [this message]
2000-04-01  0:00     ` Stuart Ballard
2000-04-01  0:00     ` Per Bothner
2000-04-01  0:00   ` Bernd Kreimeier
2000-04-01  0:00     ` Per Bothner
2000-04-01  0:00       ` Bernd Kreimeier
2000-04-01  0:00         ` Per Bothner
2000-04-01  0:00           ` Bernd Kreimeier
2000-04-01  0:00             ` Per Bothner
2000-04-01  0:00               ` Bernd Kreimeier
2000-04-01  0:00                 ` Per Bothner
2000-04-01  0:00                   ` Bernd Kreimeier
2000-04-01  0:00                   ` Alexandre Oliva
2000-04-01  0:00 Lam.Mark
2000-04-01  0:00 ` Aaron M. Renn
2000-04-01  0:00   ` Brian Jones
2000-04-01  0:00 David Pettersson
2000-04-01  0:00 ` Per Bothner
2000-04-01  0:00 Boehm, Hans

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