Jakarta Commons Jxpath can perform XPath queries over any old java bean
graph. Quite handy.
Kohsuke Kawaguchi wrote:
>
> The core problem for that would be to project XML infoset over
> JAXB-bound Java beans. Then it's relatively easy to plug Jaxen on top of
> it and get XPath support.
>
> If it can be read-only it's probably doable, but I suspect it will be
> some non-trivial work.
>
> I'd think this would make an excellent master's graduation project, if
> anyone is interested...
>
> Prashant wrote:
>> How about walking the JAXB Java Bean tree with XPath ? JXPath does
>> provide a solution but it would be nicer if we can query the JAXB Java
>> Bean tree with XPath that one uses to query XML DOM. This XPath would
>> be unaware of any customizations that JAXB codegen has introduced.
>> Introducing an annotation into Generated Code to store the XPath would
>> be one to implement this.
>>
>> I am not sure if you intended intended something on these lines.
>>
>> I think this will be very useful and reduce number of lines one needs
>> while querying Java Bean tree.
>>
>> Btw, This topic was previously discussed.[1]
>>
>> -Prashant
>>
>> [1]:http://archives.java.sun.com/cgi-bin/wa?A2=ind0302&L=jaxb-interest&P=16107
>>
>>
>>
>> Kenny MacLeod wrote:
>>> Folks,
>>>
>>> I have an idea for a possible enhancement to JAXB which I'd like to
>>> throw open to the floor. It would involve a new annotation type
>>> which takes an XPath expression, and uses that expression to bind to
>>> the field
>>> /property being annotated.
>>>
>>> This could come in handy when binding to XML documents which are not
>>> conveniently structured, perhaps those with too many levels of
>>> structure, allowing you to flatten out the structure in your class
>>> model.
>>>
>>> For example, take the following XML fragment:
>>>
>>> <book>
>>> <title>The Dice Man</title>
>>> <catalog>
>>> <isbn>0006513905</isbn>
>>> </catalog>
>>> </book>
>>>
>>> Let's say that I don't want the <catalog> intermediary type, but to
>>> flatten tht <title> and <isbn> together into the same type.
>>>
>>> With the new annotation, I could do something like this:
>>>
>>> public class Book {
>>>
>>> @XmlElement
>>> String title;
>>>
>>> @XPath(path="catalog/isbn")
>>> String isbn;
>>> }
>>>
>>> When the JAXB runtime finds the @XPath annotation, it would evaluate
>>> it against the "current" node, i.e. the <book>, and assign the result
>>> to the field.
>>>
>>> This concept could be taken much further - you could have an
>>> annotated class which cherry-picks pieces of data from deep inside
>>> the node structure and flattens them out. The ability to mix and
>>> match this approach with other JAXB binding constrructs would be
>>> quite powerful, I think.
>>>
>>> Any thoughts?
>>
>>
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