Re: URDNA2015 Implementation Question

Hello Sethi,

This implements URDNA2015:
https://github.com/setl/rdf-urdna/

It's used by a number of other related JSON-LD Java libraries that might 
be helpful:
https://github.com/filip26/titanium-json-ld
https://github.com/decentralized-identity/jsonld-common-java
https://github.com/weboftrustinfo/ld-signatures-java

all the best,
Markus

On 08.07.22 09:54, sethi shivam wrote:
> Hi Team ,
>
> I am also working on similar kind of implementation but i am more 
> looking if we have Java implementation of this .
>
>
> Could someone help me with that if there is any java implementation ?
>
> And i want to use the normalize function on offline mode.
>
>
> Best Regards
> Sethi shivam
>
> On Fri, Jul 8, 2022, 7:04 AM Dave Longley <dlongley@digitalbazaar.com> 
> wrote:
>
>
>     On 7/7/22 6:10 PM, Daniel Petranek wrote:
>     > Hello, I'm working on implementing the RDF Dataset Canonicalization
>     > algorithm[0], using the
>     https://github.com/digitalbazaar/rdf-canonize
>     > <https://github.com/digitalbazaar/rdf-canonize> implementation as a
>     > reference.
>
>     Hi Daniel!
>
>     >
>     > I've got an implementation with all the tests passing except
>     evil(1),
>     > evil(2), and evil(3), and I was wondering if you could clarify a
>     point
>     > for me - step 5.4 of the Hash N-Degree Quads algorithm which states:
>     > "For each permutation of blank node list:".
>     >
>     > I've instrumented the rdf-canonicalize library so I can inspect the
>     > order of execution, and it appears that what differs between my
>     > implementation and the Javascript one is the order of the
>     permutations.
>     > The spec doesn't say how the permutations should be ordered, and my
>     > intuition is that the order does indeed matter - though I'm
>     happy to be
>     > corrected if I'm wrong.
>     >
>     > So, here is my question(s):
>     > - Does the order of the permutations matter?
>     > - If so, what order should they be in?
>
>     Nope, the permutation order should not matter. So I would expect there
>     to be some other deviation in your implementation from the algorithm.
>
>     >
>     > The ref-canonicalize library implements the
>     Steinhaus-Johnson-Trotter
>     > algorithm, which I'm happy to do as well if necessary. But if the
>     > specific order matters I think it should be a part of the spec.
>
>     Nope, as long as you cover all the permutations, they can be in any
>     order. You may find it easier to debug if you use the same permutation
>     algorithm, but it's not necessary for correctness.
>
>     Good luck!
>
>
>     -- 
>     Dave Longley
>     CTO
>     Digital Bazaar, Inc.
>