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Posted to users@camel.apache.org by Yiannis Mavroukakis <im...@gameaccount.com> on 2010/08/13 14:08:07 UTC
XPath Builder question
I have two XPath expressions on a @RoutingSlip bean, I've noticed in the
logs that I get this
[ New I/O server worker #1-1] XPathBuilder DEBUG
Creating default XPathFactory
[ New I/O server worker #1-1] XPathBuilder DEBUG
Creating default XPathFactory
Does this mean that there are two XPathBuilder instances ?
Thanks,
Yiannis
Re: XPath Builder question
Posted by Yiannis Mavroukakis <im...@gameaccount.com>.
True, but still this doesn't justify (in my head) two of them for a single
method invocation. If your method ( I know it's an unlikely
example and bad style but bear with me) has 10 of them, that means 10 new
objects..surely it would be better to instantiate and
re-use one for as many XPath annotations in the method *per thread *and
still retain thread safety.
On 13 August 2010 20:42, Ron Smith <ro...@gmail.com> wrote:
> Note that it is not just XPath. Pretty much all of the XML parsers in the
> JDK are not thread safe. For instance, we were just having a related
> discussion here in another thread and, at the moment, I am using
ThreadLocal
> to hold on instances of SAXParser for different threads.
>
> On Fri, Aug 13, 2010 at 9:35 AM, Claus Ibsen <cl...@gmail.com>
wrote:
>
>> On Fri, Aug 13, 2010 at 2:08 PM, Yiannis Mavroukakis
>> <im...@gameaccount.com> wrote:
>> > I have two XPath expressions on a @RoutingSlip bean, I've noticed in
the
>> > logs that I get this
>> >
>> > [ New I/O server worker #1-1] XPathBuilder DEBUG
>> > Creating default XPathFactory
>> > [ New I/O server worker #1-1] XPathBuilder DEBUG
>> > Creating default XPathFactory
>> >
>> > Does this mean that there are two XPathBuilder instances ?
>> >
>>
>> All the XPath stuff in the JDK is not thread safe and you gotta create
>> new instances of the factory.
>>
>> The XPathFactory class is not thread-safe. In other words, it is the
>> application's responsibility to ensure that at most one thread is
>> using a XPathFactory object at any given moment. Implementations are
>> encouraged to mark methods as synchronized to protect themselves from
>> broken clients.
>>
>>
>> >
>> > Thanks,
>> > Yiannis
>> >
>>
>>
>>
>> --
>> Claus Ibsen
>> Apache Camel Committer
>>
>> Author of Camel in Action: http://www.manning.com/ibsen/
>> Open Source Integration: http://fusesource.com
>> Blog: http://davsclaus.blogspot.com/
>> Twitter: http://twitter.com/davsclaus
>>
>
Re: XPath Builder question
Posted by Ron Smith <ro...@gmail.com>.
Note that it is not just XPath. Pretty much all of the XML parsers in the
JDK are not thread safe. For instance, we were just having a related
discussion here in another thread and, at the moment, I am using ThreadLocal
to hold on instances of SAXParser for different threads.
On Fri, Aug 13, 2010 at 9:35 AM, Claus Ibsen <cl...@gmail.com> wrote:
> On Fri, Aug 13, 2010 at 2:08 PM, Yiannis Mavroukakis
> <im...@gameaccount.com> wrote:
> > I have two XPath expressions on a @RoutingSlip bean, I've noticed in the
> > logs that I get this
> >
> > [ New I/O server worker #1-1] XPathBuilder DEBUG
> > Creating default XPathFactory
> > [ New I/O server worker #1-1] XPathBuilder DEBUG
> > Creating default XPathFactory
> >
> > Does this mean that there are two XPathBuilder instances ?
> >
>
> All the XPath stuff in the JDK is not thread safe and you gotta create
> new instances of the factory.
>
> The XPathFactory class is not thread-safe. In other words, it is the
> application's responsibility to ensure that at most one thread is
> using a XPathFactory object at any given moment. Implementations are
> encouraged to mark methods as synchronized to protect themselves from
> broken clients.
>
>
> >
> > Thanks,
> > Yiannis
> >
>
>
>
> --
> Claus Ibsen
> Apache Camel Committer
>
> Author of Camel in Action: http://www.manning.com/ibsen/
> Open Source Integration: http://fusesource.com
> Blog: http://davsclaus.blogspot.com/
> Twitter: http://twitter.com/davsclaus
>
Re: XPath Builder question
Posted by Yiannis Mavroukakis <im...@gameaccount.com>.
Ok, but in this instance these two instantiations are for this method
@RoutingSlip
public final String[ ] route( @XPath( "//@webKey" ) final String partner ,
@XPath( value = "local-name(./node())" , resultType =
String.class ) final String operation )
Are two of them really required, since this is (I presume) a single thread ?
Y.
On 13 August 2010 15:35, Claus Ibsen <cl...@gmail.com> wrote:
> On Fri, Aug 13, 2010 at 2:08 PM, Yiannis Mavroukakis
> <im...@gameaccount.com> wrote:
>> I have two XPath expressions on a @RoutingSlip bean, I've noticed in the
>> logs that I get this
>>
>> [ New I/O server worker #1-1] XPathBuilder DEBUG
>> Creating default XPathFactory
>> [ New I/O server worker #1-1] XPathBuilder DEBUG
>> Creating default XPathFactory
>>
>> Does this mean that there are two XPathBuilder instances ?
>>
>
> All the XPath stuff in the JDK is not thread safe and you gotta create
> new instances of the factory.
>
> The XPathFactory class is not thread-safe. In other words, it is the
> application's responsibility to ensure that at most one thread is
> using a XPathFactory object at any given moment. Implementations are
> encouraged to mark methods as synchronized to protect themselves from
> broken clients.
>
>
>>
>> Thanks,
>> Yiannis
>>
>
>
>
> --
> Claus Ibsen
> Apache Camel Committer
>
> Author of Camel in Action: http://www.manning.com/ibsen/
> Open Source Integration: http://fusesource.com
> Blog: http://davsclaus.blogspot.com/
> Twitter: http://twitter.com/davsclaus
>
Re: XPath Builder question
Posted by Claus Ibsen <cl...@gmail.com>.
On Fri, Aug 13, 2010 at 2:08 PM, Yiannis Mavroukakis
<im...@gameaccount.com> wrote:
> I have two XPath expressions on a @RoutingSlip bean, I've noticed in the
> logs that I get this
>
> [ New I/O server worker #1-1] XPathBuilder DEBUG
> Creating default XPathFactory
> [ New I/O server worker #1-1] XPathBuilder DEBUG
> Creating default XPathFactory
>
> Does this mean that there are two XPathBuilder instances ?
>
All the XPath stuff in the JDK is not thread safe and you gotta create
new instances of the factory.
The XPathFactory class is not thread-safe. In other words, it is the
application's responsibility to ensure that at most one thread is
using a XPathFactory object at any given moment. Implementations are
encouraged to mark methods as synchronized to protect themselves from
broken clients.
>
> Thanks,
> Yiannis
>
--
Claus Ibsen
Apache Camel Committer
Author of Camel in Action: http://www.manning.com/ibsen/
Open Source Integration: http://fusesource.com
Blog: http://davsclaus.blogspot.com/
Twitter: http://twitter.com/davsclaus