On Nov 20, 2007 11:12 PM, Björn Granvik <[EMAIL PROTECTED]> wrote:
> Hi Viktor,
>
> Ok, now I understand better what you're getting at.
> I like the division of labor between traverse and specification. It
> makes for some sort of declarative class for the traversal.
> And the verbose version is ...verbose :-)
Ah, I re-read your previous e-mail (my eyes are tired :( ),
writing TraverseSpecification.by(Order.BREADTH_FIRST).by(Order.BREADTH_FIRST)
gives
me a compiler warning saying that static methods should be accessed in a
static way.
Regarding ReturnableEvaluator the current version of TraverseSpecification
behaves just as if you'd set it to *null
*when calling the "manual"-version of traverse(), but if people'd want it I
guess it'd be a matter of 2 minutes to
actually have a default which returns *true* for all nodes.
>
>
> Btw, ISA and ISE means?
>
Ah, sorry, too tired to type in long exception-names. :/
IAE = IllegalArgumentException
ISE = IllegalStateException
Cheers!
-Viktor
>
> Cheers,
> Björn
>
>
> Viktor Klang wrote:
> > On Nov 20, 2007 10:27 PM, Björn Granvik <[EMAIL PROTECTED]> wrote:
> >
> >
> >> Hi Viktor,
> >>
> >> Fluent interfaces are nice and makes for easy reading. But I have a
> >> question or two.
> >>
> >> What would the following mean?
> >> Traverser t = *root.traverse(by(Order.BREADTH_FIRST)
> >> .add(MyRelTypes.DADDY, Direction.OUTGOING)
> >> .add(MyRelTypes.MOMMY,Direction.INCOMING)*;
> >>
> >
> >
> > Actually, "by" is just a static method of the class
> TraverseSpecification
> > (imported statically).
> >
> > If you want to be extra verbose, the following code is also possible to
> use:
> >
> > TraverseSpecification spec = TraverseSpecification.by(
> Order.BREADTH_FIRST)
> > .setStopEvaluator(StopEvaluator.END_OF_NETWORK)
> > .setReturnEvaluator(MyReturnEvaluator)
> > .add(MyRelTypes.DADDY) //equals .add(MyRelTypes.DADDY
> > ,null)
> > .add(MyRelTypes.MOMMY,Direction.BOTH)
> > .setRandomEvaluator(myRandEval);
> >
> > In TraverseSpecification, there's 3 shorthand set-methods for
> StopEvaluator,
> > ReturnableEvaluator and RandomEvaluator
> >
> > for(Node node : root.traverse(spec))
> > foo(node);
> >
> > TraverseSpecification.by(null) yields an IAE
> > Trying to traverse a TraverseSpecification without having added any
> > relationships(/Directions) yields an ISE
> >
> > The good part of it is the no-bullshit/clear syntax + you can re-use and
> > pass the TraverseSpecifications around as you like.
> > (this means you can name them and give your code more clarity and ease
> to
> > refactor).
> >
> > Does this answer your questions?
> > Do not hesitate to ask for further info!
> >
> > Cheers
> > -Viktor
> >
> >
> >
> >> Here we have no returnEval. Would that mean a new Exception when
> >> traversing or would we default to some kind of standard evaluator?
> >> If the latter, does this mean I have to remember more conventions?
> >>
> >> Or:
> >>
> >> Traverser t = *root.traverse(by(Order.BREADTH_FIRST)
> >> .add(MyRelTypes.MOMMY,Direction.INCOMING)
> >> .set(StopEvaluator.END_OF_NETWORK)
> >> .add(MyRelTypes.DADDY, Direction.OUTGOING)
> >> .set(returnEval)
> >> .by(Order.DEPTH_FIRST))*;
> >>
> >> Notice the double use of "by" and the sort of odd "add-set-add-set".
> >> In some cases where fluent interfaces are used (or the "reversed sql"
> >> resemblence in Linq) I'm uncertain whether or not there is a mechanism
> >> to express things in the correct order.
> >> For instance; Is there some kind of state that will help me do
> >> "code-completion" (for instance the by-method only returns an object
> >> that has add or set methods).
> >> Is there some kind of state that will recognize the double use of "by"
> >> in the code above?
> >>
> >> I didn't mean to sound pessimistic about your idea, it's just that I've
> >> had these questions running around my head for some of the fluent
> >> interface implementations that I've seen.
> >>
> >> Regards,
> >> Björn
> >>
> >> Ps. I like having patches served, but I'm just a user of Neo so someone
> >> else would have to give you a proper answer :-)
> >>
> >>
> >>
> >> Viktor Klang wrote:
> >>
> >>> Greetings people!
> >>>
> >>> How'd you like to be able to write stuff like this?
> >>>
> >>> ReturnableEvaluator returnEval = new ReturnableEvaluator(){
> >>> @Override
> >>> public boolean isReturnableNode(TraversalPosition
> >>>
> >> currentPos) {
> >>
> >>> return (currentPos.currentNode().hasProperty("name"));
> >>> }
> >>> };
> >>>
> >>> Traverser t = *root.traverse(by(Order.BREADTH_FIRST)
> >>> .add(MyRelTypes.DADDY, Direction.OUTGOING)
> >>> .add(MyRelTypes.MOMMY,Direction.INCOMING)
> >>> .set(StopEvaluator.END_OF_NETWORK)
> >>> .set(returnEval))*;
> >>>
> >>> for(Node node : t)
> >>> doFunStuffWith(node);
> >>>
> >>> Or even:
> >>>
> >>> TraverseSpecification spec = *by(Order.BREADTH_FIRST)
> >>> .add(MyRelTypes.DADDY, Direction.OUTGOING)
> >>> .add(MyRelTypes.MOMMY,Direction.INCOMING)
> >>> .set(StopEvaluator.END_OF_NETWORK)
> >>> .set(returnEval);
> >>>
> >>> *for(Node node : *someNode.traverse(spec)*)
> >>> doFunStuffWith(node);*
> >>> *
> >>> for(Node node : *someOtherNode.traverse(spec)*)
> >>> doFunStuffWith(node);*
> >>>
> >>> *Interested?
> >>> Code is already written and I've played with it a bit.
> >>> How do you like your patches served? :)
> >>>
> >>> Best regards
> >>> -Viktor*
> >>>
> >>> **
> >>>
> >>> *
> >>> _______________________________________________
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> >>>
> >>>
> >>>
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> >>
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