There are elements of that - see CommonsRDF - though here the operations
are whole objects (dataset - to query is as a Stream<Tuple> would to
collect the tuples).
It is also like building up a executable pipeline of operations but not
doing it until the final step which allows optimization of the pipeline.
c.f. Apache spark.
On 16/12/16 15:43, A. Soroka wrote:
It seems to me that these ideas begin to border on the Stream API, with something
like Stream<Tuple> at work.
---
A. Soroka
The University of Virginia Library
On Dec 15, 2016, at 3:46 PM, Andy Seaborne <a...@apache.org> wrote:
A more considered solution:
https://gist.github.com/afs/2b8773d10cbe4bc1161e9851de02b3eb
Andy
On 14/12/16 12:52, Andy Seaborne wrote:
On 14/12/16 11:23, Martynas Jusevičius wrote:
But that would still require the functional subclasses of Query?
Yes, but it required no changes to the jena code. There could be a
library of such utilities.
static <T,X> T apply(X object, Function<X, T> f) {
return f.apply(object);
}
static <X> void apply(X object, Consumer<X> c) {
c.accept(object);
}
Dataset dataset = ... ;
Select selectQuery = new Select("SELECT * { ?s ?p ?o}");
ResultSet rs = selectQuery.apply(dataset);
Consumer<ResultSet> rsp = (t)->ResultSetFormatter.out(t);
apply(apply(dataset, selectQuery), rsp);
(because Consumer isn't a Function<,Void> :-()
Andy
On Wed, Dec 14, 2016 at 11:37 AM, Andy Seaborne <a...@apache.org> wrote:
On 12/12/16 21:45, Martynas Jusevičius wrote:
Well, this probably requires some generic method(s) in Dataset/Model
as well, something like:
T apply(Function<Dataset, T> f);
This would allow nice chaining of multiple queries, e.g DESCRIBE and
SELECT:
ResultSet results = dataset.apply(describe).apply(select);
No need to extend dataset and model and the rest to get experimenting:
static <T,X> T apply(X object, Function<X, T> f) {
return f.apply(object);
}
// BiFunction<X, Function<X, T>, T>
then
ResultSet results = apply(
apply(dataset, describe),
select);
The function f does have any access to the internals of a specific
dataset
so it does not need to be a method of Dataset.
There is a style thing about how it looks if you are not used to reading
functional application (i.e. backwards!).
Andy
Seems more elegant to me than all the QueryExecution boilerplate.
On Mon, Dec 12, 2016 at 9:00 PM, A. Soroka <aj...@virginia.edu> wrote:
What are the kinds of usages to which you are imagining these kind of
types being put?
---
A. Soroka
The University of Virginia Library
On Dec 12, 2016, at 2:03 PM, Martynas Jusevičius
<marty...@graphity.org>
wrote:
Hey,
has Jena considered taking advantage of the functional features in
Java
8?
What I have in mind is interfaces like:
Construct extends Query implements Function<Dataset, Model>
Describe extends Query implements Function<Dataset, Model>
Select extends Query implements Function<Dataset, ResultSet>
Ask extends Query implements Function<Dataset, ResultSet>
Martynas
atomgraph.com
