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From "Alexey Petrenko" <alexey.a.petre...@gmail.com>
Subject Re: Suggestion (was: Re: [jira] Closed: (HARMONY-932) [classlib][nio]java.nio.?hannel.DatagramChannel.read(ByteBuffer[] , int, Integer.MAX_VALUE) throws NotYetConnectedException while RI throws IndexOutOfBoundsException)
Date Fri, 21 Jul 2006 10:29:21 GMT
2006/7/21, Paulex Yang <paulex.yang@gmail.com>:
> Alexey Petrenko wrote:
> > My two cents... :)
> >
> > Put all the array size checking code in one place is a good idea. Code
> > reuse is always good idea.
> >
> > But do not forget that Java has 2 problems here:
> > 1. It can not inline methods or include code in java file
> > 2. Method call is a long operation.
> AFAIK, the final/static/private(i.e. non-overriddable) methods have
> chance to be inlined by JIT or so? (waiting for JIT guys correct me)
As far as I know ALL the methods are have chance to inline. The
question is how fast it will be done.

> > So huge number of additional method calls can significantly downgrade
> > the performance...
> Performance is a complex issue, my rule of thumb is that without
> benchmarking and bottleneck identification, the performance optimization
> probably misses the target. Further, codes with good structure are
> easier to be optimized later, while duplicate codes are probably evil...
> >
> > Probably VM JIT guys will correct me.
> >
> > Anyway... I think that the best plays for such tool methods is a misc
> > module, not util.
> Why does it matters in which module? I mean, does this related to
> performance?
I did not talk about performance here :)

> >
> > SY, Alexey
> >
> > 2006/7/21, Andrew Zhang <zhanghuangzhu@gmail.com>:
> >> Hi Vladimir,
> >>
> >> I noticed the same problem is existing in many places of NIO module.
> >>
> >> How about writing a utility function for array index exception check?
> >> like:
> >>
> >> void assertArrayIndex(Object[] array, int offset, int length){
> >>  if(offset < 0 || length < 0 || (long)offset + (long)length >
> >> array.length
> >> ){
> >>     throw new IndexOutOfBoundsException();
> >>  }
> >> }
> >>
> >> How do you think about it? Any suggestions?
> >>
> >> Thanks!
> >> Best regards,
> >>
> >>
> >> On 7/21/06, Paulex Yang (JIRA) <jira@apache.org> wrote:
> >> >
> >> >     [ http://issues.apache.org/jira/browse/HARMONY-932?page=all ]
> >> >
> >> > Paulex Yang closed HARMONY-932.
> >> > -------------------------------
> >> >
> >> >    Estimated Complexity: Novice
> >> >
> >> > Verified by Vladimir.
> >> >
> >> > > [classlib][nio]java.nio.?hannel.DatagramChannel.read(ByteBuffer[]
> >> , int,
> >> > Integer.MAX_VALUE) throws NotYetConnectedException while RI throws
> >> > IndexOutOfBoundsException
> >> > >
> >> >
> >> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------
> >>
> >> > >
> >> > >                 Key: HARMONY-932
> >> > >                 URL:
> >> http://issues.apache.org/jira/browse/HARMONY-932
> >> > >             Project: Harmony
> >> > >          Issue Type: Bug
> >> > >          Components: Classlib
> >> > >            Reporter: Vladimir Ivanov
> >> > >         Assigned To: Paulex Yang
> >> > >         Attachments: DatagramChannelImpl.patch
> >> > >
> >> > >
> >> > > The Harmony methods
> >> java.nio.?hannel.DatagramChannel.read/write(ByteBuffer[]
> >> > , int, Integer.MAX_VALUE) throws NotYetConnectedException while RI
> >> throws
> >> > IndexOutOfBoundsException.
> >> > > ==================== test.java ======================
> >> > > import java.nio.channels.*;
> >> > > import java.nio.*;
> >> > > public class test  {
> >> > >     public static void main (String[] args) {
> >> > >         try {
> >> > >             DatagramChannel.open().read(new ByteBuffer[] {}, 2,
> >> > Integer.MAX_VALUE);
> >> > >         } catch (Exception e) {
> >> > >             e.printStackTrace();
> >> > >         }
> >> > >         try {
> >> > >             DatagramChannel.open().write(new ByteBuffer[] {}, 2,
> >> > Integer.MAX_VALUE);
> >> > >         } catch (Exception e) {
> >> > >             e.printStackTrace();
> >> > >         }
> >> > >     }
> >> > > }
> >> > > =================================================
> >> > > Output:
> >> > > C:\tmp\tmp17>C:\jdk1.5.0_06\bin\java.exe -cp . -showversion test
> >> > > java version "1.5.0_06"
> >> > > Java(TM) 2 Runtime Environment, Standard Edition (build
> >> 1.5.0_06-b05)
> >> > > Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode)
> >> > > java.lang.IndexOutOfBoundsException
> >> > >         at
> >> sun.nio.ch.DatagramChannelImpl.read(DatagramChannelImpl.java
> >> > :366)
> >> > >         at test.main(test.java:8)
> >> > > java.lang.IndexOutOfBoundsException
> >> > >         at
> >> sun.nio.ch.DatagramChannelImpl.write(DatagramChannelImpl.java
> >> > :429)
> >> > >         at test.main(test.java:13)
> >> > > C:\tmp\tmp17>C:\jrockit-jdk1.5.0-windows-ia32\bin\java.exe -cp
.
> >> > -showversion test
> >> > > java version "1.5.0"
> >> > > Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
> >> > > BEA WebLogic JRockit(R) (build dra-38972-20041208-2001-win-ia32,
> >> > R25.0.0-75, GC: System optimized over throughput (initial strategy
> >> > singleparpar))
> >> > > OutOfMemoryError
> >> > > -------end of stacktrace
> >> > > C:\tmp\tmp17>C:\harmony\trunk_0427\deploy\jdk\jre\bin\java.exe
-cp .
> >> > -showversion test
> >> > > java version 1.5 (subset)
> >> > > (c) Copyright 1991, 2006 The Apache Software Foundation or its
> >> > licensors, as applicable.
> >> > > java.nio.channels.NotYetConnectedException
> >> > >         at
> >> >
> >> org.apache.harmony.nio.internal.DatagramChannelImpl.checkOpenConnected(
> >> > DatagramChannelImpl.java:567)
> >> > >         at org.apache.harmony.nio.internal.DatagramChannelImpl.read(
> >> > DatagramChannelImpl.java:387)
> >> > >         at test.main(test.java:8)
> >> > > java.nio.channels.NotYetConnectedException
> >> > >         at
> >> >
> >> org.apache.harmony.nio.internal.DatagramChannelImpl.checkOpenConnected(
> >> > DatagramChannelImpl.java:567)
> >> > >         at
> >> org.apache.harmony.nio.internal.DatagramChannelImpl.write(
> >> > DatagramChannelImpl.java:477)
> >> > >         at test.main(test.java:13)
> >> > >
> >> >
> >> C:\tmp\tmp17>C:\harmony\drlvm\trunk\build\win_ia32_msvc_debug\deploy\jre\bin\ij
> >>
> >> > -Dvm.assert_dialog=false -cp . -showversion test
> >> > > Apache Harmony DRLVM HEAD-4807 (2006-05-02), Windows/ia32/msvc 1310,
> >> > debug
> >> > > java.nio.channels.NotYetConnectedException
> >> > >         at
> >> >
> >> org.apache.harmony.nio.internal.DatagramChannelImpl.checkOpenConnected(
> >> > DatagramChannelImpl.java:567)
> >> > >         at org.apache.harmony.nio.internal.DatagramChannelImpl.read(
> >> > DatagramChannelImpl.java:387)
> >> > >         at test.main(test.java:8)
> >> > > java.nio.channels.NotYetConnectedException
> >> > >         at
> >> >
> >> org.apache.harmony.nio.internal.DatagramChannelImpl.checkOpenConnected(
> >> > DatagramChannelImpl.java:567)
> >> > >         at
> >> org.apache.harmony.nio.internal.DatagramChannelImpl.write(
> >> > DatagramChannelImpl.java:477)
> >> > >         at test.main(test.java:13)
> >> >
> >> > --
> >> > This message is automatically generated by JIRA.
> >> > -
> >> > If you think it was sent incorrectly contact one of the
> >> administrators:
> >> > http://issues.apache.org/jira/secure/Administrators.jspa
> >> > -
> >> > For more information on JIRA, see:
> >> http://www.atlassian.com/software/jira
> >> >
> >> >
> >> >
> >>
> >>
> >> --
> >> Andrew Zhang
> >> China Software Development Lab, IBM
> >>
> >>
> >
> >
>
>
> --
> Paulex Yang
> China Software Development Lab
> IBM
>
>
>
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>


-- 
Alexey A. Petrenko
Intel Middleware Products Division

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