Adam Lally wrote:
On 12/22/06, Marshall Schor <[EMAIL PROTECTED]> wrote:
If we had filtering predicates as part of an index specification,
then we
could create indexes over subsets of types quite arbitrarily. Could this
more general mechanism serve this purpose better than views?
I'm not sure what you mean, "subets of types". Do you mean "subsets
of objects (FeatureStructures)", as in a filter that checks arbitrary
feature values to decide whether an object gets added to the index?
Yes.
Could be... this sounds like it's saying that an index is a way to
optimize what could be implemented by an annotator using a filter over
all FS in the CAS followed by a sort.
Right.
> Going back to my hypothetical annotator that created an annotation off
> the base CAS by calling CAS.createAnnotation(begin, end, Sofa). In
> our current implementation this isn't useful because the annotation
> has to be indexed to be retrievable, and the only way to index it is
> to add it to a view. Are there any other options we could consider
This doesn't seem correct: an annotation doesn't have to be indexed
to be
retrievable - it could be referenced by some chain of FS, with the
starting
FS of course being indexed So I could have an FSArray for instance, of
Annotations, and index the FSArray.
Yes, of course; I glossed over that detail. I don't think it really
affects my point, though. The only way to index the FSArray
containing my annotation would be to add it to a view, which I don't
want to do. Is there a way to make my Annotation accessible from the
base CAS without having to go through a view first?
I guess I missed the point ...
Indexes are sometimes used as a performance optimization, but other
times
they're part of a component's logic - as when a component depends on
a particular sorting order.
The annotator could do the sorting itself. But I'll correct my
statement to say that indexes are both a performance optimization and
a convenience.
I think you may be technically correct, but my point was that the users
tend to
think of indexes differently (more than
just optimizations and conveniences) - they think
of them as part of their component logic. I'm thinking of the users
that use
the special iterators over Annotation types, and depend on things like Type
Priorities for correct operation of their components.
-Marshall
