Comments on: Simple and efficient XML parsing using JAXB 2.0

By: Nathaniel Harward

Nathaniel Harward — Wed, 03 Mar 2010 14:49:06 +0000

And here's the link which I conveniently forgot

http://code.google.com/p/ndh-commons/

By: Nathaniel Harward

Nathaniel Harward — Wed, 03 Mar 2010 14:47:43 +0000

I realize this post is rather old, but in the event anyone (including Sam) is still reading it — this post got me thinking and I created something (free, GPL) somewhere in between the examples here and the LDK+ library mentioned by Lolke. It's in its infancy, but perhaps someone would find it useful.

By: Java – Object XML Mapping « WebMoli – Rediscover the Basics

Java – Object XML Mapping « WebMoli – Rediscover the Basics — Wed, 18 Nov 2009 02:30:42 +0000

[...] http://www.javarants.com/2006/04/30/simple-and-efficient-xml-parsing-using-jaxb-2-0/comment-page-1/ [...]

By: Joe

Joe — Mon, 28 Sep 2009 13:19:58 +0000

Thanks for your great effort.
When i tried to test the code which you wrote, it throws the following exception while unmarshalling

java.lang.IllegalStateException: reader must be on a START_ELEMENT event, not a 4 event
at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:368)
at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:354)
at com.fawry.test.TestJAXBUnmarshaller.testParseEfficiently(TestJAXBUnmarshaller.java:72)
at com.fawry.test.TestJAXBUnmarshaller.main(TestJAXBUnmarshaller.java:31)

I hope if you have answer to my question

By: Joe

Joe — Mon, 28 Sep 2009 06:19:58 +0000

By: Lolke Dijkstra

Lolke Dijkstra — Fri, 19 Jun 2009 05:58:16 +0000

Hi Sam,

Thanks for your swift reply!

Actually I've developed an alternative approach based on SAX and MDE. More specifically, what I do, I use a code generator to generate the code from the schema.

The approach uses a common framework and the generator extends these framework classes. In principle for each complextype a JavaBean class is generated, but whether or not this class should be stored with its parent is configurable. For more information please see my website: http://www.dijkstra-ict.com

I also wrote an article that explains the approach. You can find it on the site.
Let me know if you're interested to see how it compares to the alternative.

Kind regards,
Lolke Dijkstra

By: spullara

spullara — Thu, 18 Jun 2009 16:52:04 +0000

Hi Lolke,

There is no way for JAXB to not parse the children of an element that you unmarshall. For your case I would use StAX to go all the way down to the Batch object then use JAXB to parse each individual transaction.

Sam

By: Lolke Dijkstra

Lolke Dijkstra — Thu, 18 Jun 2009 12:32:31 +0000

This is very interesting and it probably works for many cases but I was wondering would it work if you need both the encompassing element and its children. For example:

some generic info
<..>

...
...

...
<..>

So now I would like to process the batch having an object of type Batch:

class Batch {
public String getInfo()...
public List getTxs()...
}

and the Tx:

class Tx {
SrcType getScr()...
DstType getDst()...
...
}

Obviously, using the sparse (memory efficient) approach I would expect the getTxs() to just return an empty List, whereas in the straightforward approach this list would contain the actual Tx children.

So, the thing is, when you use JAXB to parse the unmarshall the parent, it there a way to instruct it to not store the transaction in the List and use JAXB to process these separately?

Thanks,
Lolke

By: spullara

spullara — Thu, 29 Jan 2009 14:59:17 +0000

Parsing the entire document.

By: Neel Sukhadia

Neel Sukhadia — Thu, 29 Jan 2009 14:21:10 +0000

The performance measurements are for for the entire document or for a single element's parse?Thanks.