Hi Raul,
Could you think of a way we can fix the problem without having a
significant performance hit. This clearly is a blocking issue for me. If
eventually we decide to change the comparisons to use String.equals() I
could give you the list of all relevant occurrences in the code.
Thanks,
Vishal
Raul Benito wrote:
> Hi Sean,
>
> The penalty hit is taken when the strings are not equal, sadly of the
> same length.
> And have a lot of common begging characters. That is sadly a common
> problem with namespaces URI, they are more or less equal in length and
> have a lot of damn http://.../... or urn:....: whatever at the
> begining. And that is why Xerces and other DOM implementations intern
> namespaces URI.
>
> I have profile and it takes a lot of time.
> My point is that all the parsers I know do the intern (or it did when
> I do the implementation). And this is an old commit 8 months old(it is
> true that it is not yet on a official release), and it takes a
> measurable hit if not use in small messages(the kind of one that are
> in xml protocols).
>
> So I will first check other options (change the configuration of the
> offending parser with a
> feature[http://xerces.apache.org/xerces2-j/features.html] ).
> If it does not work I will change from == to equals, but I will let
> this as last resort.
>
> On 10/5/06, Sean Mullan <[EMAIL PROTECTED]> wrote:
>> String.equals will work for both interned and non-interned Strings,
>> since it first checks if they are a reference to the same object. So
>> using String.equals seems safer and should be comparable performance I
>> would think. But maybe I'm missing something?
>>
>> --Sean
>>
>> Vishal Mahajan wrote:
>> > Do others also have views on this discussion?
>> >
>> > Thanks,
>> > Vishal
>> >
>> > Vishal Mahajan wrote:
>> >> Hi Raul,
>> >>
>> >> The parser that I am working with clearly doesn't intern element
>> >> namespace strings which is the reason I ran into this problem. And
>> >> actually I am not sure whether it's a good idea for a parser to
>> intern
>> >> element namespace strings given that there could be huge number of
>> >> elements being parsed and there's a potential risk of running out of
>> >> memory. Also you mention that xerces might be interning namespace
>> >> stings but looking at their code I was unable to find that. Can you
>> >> point me to the relevant piece of code?
>> >>
>> >> Thanks,
>> >>
>> >> Vishal
>> >>
>> >> Raul Benito wrote:
>> >>> Vishal the problem is that this codes is called gazillion of times,
>> >>> and even it
>> >>> seems a small thing, it takes a lot of accumulated time, I even
>> think
>> >>> in remove this checking altogether or control it by a property.
>> >>> Perhaps there is a feature set in your DOM parser that interns the
>> >>> namespaces. I have test with several DOM parsers (xerces, xmlbeans,
>> >>> jaxb) and all of them the namespaces strings are interns.
>> >>> If you are not able too toggle the behavior, We can begin to
>> think in
>> >>> other possibilities (create code on the fly, create an interface
>> with
>> >>> one implementation or the other a let the JVM inline it). But I
>> think
>> >>> will be the last resort.
>> >>>
>> >>> Regards,
>> >>> Raul
>> >>>
>> >>> On 10/2/06, Vishal Mahajan <[EMAIL PROTECTED]> wrote:
>> >>>> Any signature verification was failing for me, and I have a
>> different
>> >>>> DOM implementation in my environment, so probably you are right.
>> It was
>> >>>> such a basic error that it had to be something like this. In any
>> >>>> case, I
>> >>>> think we should keep string comparison safe.
>> >>>>
>> >>>> Vishal
>> >>>>
>> >>>> Raul Benito wrote:
>> >>>> > Hi Vishal,
>> >>>> >
>> >>>> > The namespaces strings are intern, at least in xerces.
>> >>>> >
>> >>>> > Can you post the code that is failing?
>> >>>> >
>> >>>> > On 10/2/06, Vishal Mahajan <[EMAIL PROTECTED]> wrote:
>> >>>> >> This problem was not allowing successful creation of
>> signature space
>> >>>> >> elements. Fix attached.
>> >>>> >>
>> >>>> >> Vishal
>> >>>> >>
>> >>>> >>
>> >>>> >>
>> >>>> >> Index: ElementProxy.java
>> >>>> >>
>> ===================================================================
>> >>>> >> --- ElementProxy.java (revision 451991)
>> >>>> >> +++ ElementProxy.java (working copy)
>> >>>> >> @@ -281,7 +281,7 @@
>> >>>> >>
>> >>>> >> String localnameIS =
>> >>>> this._constructionElement.getLocalName();
>> >>>> >> String namespaceIS =
>> >>>> this._constructionElement.getNamespaceURI();
>> >>>> >> - if ((namespaceSHOULDBE!=namespaceIS) ||
>> >>>> >> + if (!namespaceSHOULDBE.equals(namespaceIS) ||
>> >>>> >> !localnameSHOULDBE.equals(localnameIS) ) {
>> >>>> >> Object exArgs[] = { namespaceIS +":"+ localnameIS,
>> >>>> >> namespaceSHOULDBE +":"+ localnameSHOULDBE};
>> >>>> >>
>> >>>> >>
>> >>>> >>
>> >>>> >
>> >>>> >
>> >>>>
>> >>>>
>> >>>>
>> >>>
>> >>>
>> >>
>> >>
>> >
>> >
>>
>>
>
>
