(import s2j)

;; Notes: calls to statics:
;; need a object of the righ tclass or a suiabely typed null.
;; That is, 
;;   (out (java-null <ResultSetFormatter>) rs)
;; Not that clean but it would be better to have a library that
;; presented ARQ in a scheme-like
;; way, not have plain calls to the Java world.
;; Work-in-progress 


(java-class '|java.lang.String|)

(define-java-classes
  (<jstring>      |java.lang.String|)
  (<QueryFactory> |com.hp.hpl.jena.query.QueryFactory|)
  (<QueryExecutionFactory> |com.hp.hpl.jena.query.QueryExecutionFactory|)
  (<ResultSetFormatter> |com.hp.hpl.jena.query.ResultSetFormatter|)
  (<Query> |com.hp.hpl.jena.query.Query|)
  )

(define str (->jstring "SELECT * FROM <file:D.ttl> { ?s ?p ?o }"))
(define base (->jstring "http://example/"))

(define-generic-java-method jToString |toString|)
(define-generic-java-method jCreate |create|)
(define-generic-java-method execSelect |execSelect|)
(define-generic-java-method out |out|)

;;--- Define factories.  One argument methods only.
(define (QueryFactory method arg)
  (method (java-null <QueryFactory>) arg))
  
;;(apply method (append (list (java-null <QueryFactory>) args))))

(define (QueryExecutionFactory method arg)
  (method (java-null <QueryExecutionFactory>) arg))

(define (ResultSetFormatter method args)
  (method (java-null <ResultSetFormatter>) args))

;; ---- Better: a "static method" mechanism.

(define (static-java-method method class)
  (lambda args
    (apply method (cons (java-null class) args))))

;; ----
;; Wrapped factory/static calls.

(define (make-query s)
  ((static-java-method jCreate <QueryFactory>) s))

(define (make-qexec args)
  ((static-java-method jCreate <QueryExecutionFactory>) args))

(define (rs-write rs)
  (ResultSetFormatter out rs))

;; ----
;; Application

(define query (make-query str))

(define qExec (make-qexec query))

(define rs (execSelect qExec))

(define (next? iter)
  (->boolean 
   ((generic-java-method '|hasNext|) iter)))

(define (x iter)
  (cond ( (not (next? iter)) '() )
	(else
	 (let ((b ((generic-java-method '|nextBinding|) iter)))
	   (write (->string (jToString b)))
	   (newline)
	   (x iter)
	  ))))

(x rs)
(newline)

;; And again, then use the resultSetFormatter.

(rs-write
 (execSelect (make-qexec str)))