XOM API for Processing XML with Java

[dvholten AT computer.org]

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/
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