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  • From: dvholten AT computer.org
  • To: xom-interest AT lists.ibiblio.org
  • Cc:
  • Subject: Antwort: RE: [XOM-interest] Attributes performance patch
  • Date: Mon, 22 Nov 2004 13:31:16 GMT

counting cycles doesnt make too much sense when some method-calls are done
inside the loop.
for my taste, i wouldnt use that countdown-loops for 'normal' loops -
they are not the 'standard idiom' for an iteration over some
list-elements.
I stop reading and have to understand how the loops counts: n..0 ? n..1 ??
The standard-loop is a no brainer..

if there really is a hotspot, i would investigate, why the iterator is a
problem here.
tja - here might be a problem: the iterator checks for concurrent
modifications,
the index-access doesnt. What if two calls to Attributes.add() happen at
the same time?
What if Attributes.remove() is called while an add() is under way??

dvholten
>From whoschek AT lbl.gov Mon Nov 22 11:27:14 2004
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From: Wolfgang Hoschek <whoschek AT lbl.gov>
Subject: Re: [XOM-interest] Attributes performance patch
Date: Mon, 22 Nov 2004 08:27:10 -0800
To: Elliotte Harold <elharo AT metalab.unc.edu>
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On Nov 22, 2004, at 3:07 AM, Elliotte Harold wrote:

> A fix is in CVS. Thanks for the report.

Attributes copy() {

Attributes result = new Attributes();
int size = attributes.size();
result.attributes.ensureCapacity(size);
for (int i = 0; i < size(); i++) {
result.attributes.add(this.get(i).copy());
}
return result;

}

should better read:

Attributes copy() {

Attributes result = new Attributes();
int size = attributes.size();
result.attributes.ensureCapacity(size);
for (int i = 0; i < size; i++) { // WH DELTA HERE
result.attributes.add(this.get(i).copy());
}
return result;

}

and as stated and documented in my previous mail there is no need to
loop any further, hence

void checkPrefixConflict(Attribute attribute) {

String prefix = attribute.getNamespacePrefix();
String namespaceURI = attribute.getNamespaceURI();

// Look for conflicts
int size = this.size();
for (int i = 0; i < size; i++) {
Attribute a = (Attribute) attributes.get(i);
if (a.getNamespacePrefix().equals(prefix)
&& !(a.getNamespaceURI().equals(namespaceURI))) {
throw new NamespaceConflictException(
"Prefix of " + attribute.getQualifiedName()
+ " conflicts with " + a.getQualifiedName());
}
}

}


should better read:

void checkPrefixConflict(Attribute attribute) {

String prefix = attribute.getNamespacePrefix();
String namespaceURI = attribute.getNamespaceURI();

// Look for conflicts
int size = this.size();
for (int i = 0; i < size; i++) {
Attribute a = (Attribute) attributes.get(i);
// if (a.getNamespacePrefix().equals(prefix)
// && !(a.getNamespaceURI().equals(namespaceURI))) {
// throw new NamespaceConflictException(
// "Prefix of " + attribute.getQualifiedName()
// + " conflicts with " + a.getQualifiedName());
// }
if (a.getNamespacePrefix().equals(prefix)) {
if (a.getNamespaceURI().equals(namespaceURI)) return; //
no need to look further
throw new NamespaceConflictException(
"Prefix of " + attribute.getQualifiedName()
+ " conflicts with " + a.getQualifiedName());
}
}

}



-----------------------------------------------------------------------
Wolfgang Hoschek | email: whoschek AT lbl.gov
Distributed Systems Department | phone: (415)-533-7610
Berkeley Laboratory | http://dsd.lbl.gov/~hoschek/
-----------------------------------------------------------------------




  • Antwort: RE: [XOM-interest] Attributes performance patch, dvholten, 11/22/2004

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