The value of next on the QueryResult is not being checked. If next returns false, the message below will be seen as if next had not been called. The getInt method and other "get" methods could throw a JessException with a different message when called after next returns FALSE, but doesn't.
Bob Kirby At 10:14 AM 8/18/2008, Seyed Hossein wrote: >Hi, >I'm trying to write a program that asks a user his telephone number in GUI, >then searches a database for that phone # using defquery, and outputs some >results. But when I run it I get an error as below. > > >Jess reported an error in routine QueryResult.get >while executing (call ?result getInt ca) >while executing (printout t ?text crlf (call ?result getInt ca)) >while executing deffunction running-query >while executing (running-query ?text) >while executing deffunction read-input >while executing (read-input <Java-Object:java.awt.event.ActionEvent>). > Message: The cursor is before the first row; you must call next() before > accessing query result . > >Since I called next() before accessing query result, I thought the error might >be caused by calling the defquery within a deffunction. Following is the >program I wrote. I'd appreciate any help. > > >;(watch all) >(import javax.swing.*) >(import javax.swing.JFrame) >(import java.awt.event.ActionListener) >(import java.awt.BorderLayout) >(import java.awt.Color) >(import javax.swing.*) >(import java.awt.*) >(import java.awt.event.*) > > > > >(defglobal ?*f* = (new JFrame "Testing")) >(defglobal ?*c* = (?*f* getContentPane)) >(defglobal ?*apanel* = (new JPanel)) >(defglobal ?*afield* = (new JTextField 40)) >(defglobal ?*afield-ok* =(new JButton OK)) > > >(?*apanel* add ?*afield*) >(?*apanel* add ?*afield-ok*) >((?*f* getContentPane) add ?*apanel* >(get-member BorderLayout CENTER)) >(?*f* validate) >(?*f* repaint) >(?*c* add (new JLabel "What is the phone number? ") (BorderLayout.NORTH)) > > > > >(deftemplate conditions > (slot telnumb) > (slot adr) > (slot esc) > (slot sta) > (slot car)) > > >(deffacts testdata > (conditions (telnumb 4978548) (adr 8) (esc 0) (sta 4) (car 4)) > (conditions (telnumb 8754655) (adr 5) (esc 0) (sta 1) (car 6)) > (conditions (telnumb 9856211) (adr 1) (esc 0) (sta 7) (car 2)) > (conditions (telnumb 5284877) (adr 8) (esc 1) (sta 2) (car 5)) > (conditions (telnumb 9845652) (adr 8) (esc 0) (sta 1) (car 1)) > ) > > >(defquery search-by-telnumb > "Finds locations with given telephone number" > (declare (variables ?tn)) > (conditions (telnumb ?tn) (adr ?ad) (esc ?es) (sta ?st) (car ?ca))) > > >(deffunction running-query (?text) >(bind ?result (run-query* search-by-telnumb ?text)) >(?result next) >(printout t ?text crlf (?result getInt ca)) >) > > >(deffunction read-input (?EVENT) >(bind ?text (sym-cat (?*afield* getText))) >(running-query ?text) >) > >(bind ?handler (new jess.awt.ActionListener read-input (engine))) >(?*afield* addActionListener ?handler) >(?*afield-ok* addActionListener ?handler) > >(?*f* setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE)) > > >(?*f* pack) >(?*f* setSize 520 150) >(?*f* setVisible TRUE) > > >Thank you, >Seyed
