Re: [Vtd-xml-users] Random Access Proposal (take 2)

[Rodrigo C. <rn...@gm...>]

Nah... given what i understand about the internal structure making it 
the new document root is not trivial, i think.

But you could get away with:

- A bookmark/position saving system, aka the (in)famous SimpleContext 
class?...

- A function evaluating:

boolean SimpleContext.isSunOf(Simplecontext ctx); //this should be 
simple and efficient to implement

Regards,

Rodrigo

Mark Swanson wrote:
> Rodrigo Cunha wrote:
>> For a SimpleContext, or something similar:
>>
>> The comparison operator could just compare the arrays containing the 
>> internal state of Navigator.
>>
>> The hashcode would be the XOR of all elements in the array, that 
>> implements java hashcode and equals in a compatible way with the 
>> assumed rules in java libraries.
>>
>> Jimmy, I think my "SimpleContext" or whatever you want to call it, if 
>> properly implemented and perhaps with a few extra functions  could 
>> solve all the problems of random access.
>>
>> I think we just want something with the functionality of push() and 
>> pop() but that can be extracted and kept outside, memorizing the 
>> equivalent of a single stack position, and perhaps with a bit more 
>> functionality.
>
> It will be interesting to see how much / little info we can get away 
> with saving and still be able to start an XPath expression from an 
> arbitrary point.
>
> Important: it may make the implementation easier if we make the 
> arbitrary starting point the new document root - just for xpath 
> evaluation purposes. I think this is perfect, actually. I don't want 
> anything except for the node and its children - that's why I'm 
> explicitly pointing there in the first place.
>
> F.E.
> (forgive the illegal simplified syntax..)
>
> aaa
>   bbb
>     ccc    <- Index saved, new root for xpath eval.
>       eee
>       fff
>     /ccc
>     dd
> ...
>
> I'd want to say something like this:
>
> vtdNav.toElement(cccIndex); // reset cursor to ccc
> ap.selectXPath("/ccc/*")
>
> Cheers.
>