8:58 p.m.
hi there,
I have a simple fact class:
public class Msg {
private Long lo = 5l;
private double dbl = 5.5;
public Long getLo() {
return lo;
}
public void setLo(Long lo) {
this.lo = lo;
}
public double getDbl() {
return dbl;
}
public void setDbl(double dbl) {
this.dbl = dbl;
}
}
and a simple drl program:
package com.sample
import com.sample.Msg;
rule "Hello World"
when
m:Msg(lo >= dbl)
then
System.out.println( "hello world" );
System.out.println(m.getLo());
System.out.println(m.getDbl());
end
I simply compare the Long value, which is 5, to the double value ,which is
5.5, with operator '>=', and the output is:
hello world
5
5.5
but it can't be ,cause 5 is less than 5.5.
then I modified the drl program a bit:
m:Msg(lo == dbl)
It successfully prints out the message as well.It seems that drools treated
the double value '5.5' as '5' in comparing...
Is this a bug or something?What could I do to correct it?
thanks.
5:14 a.m.
New subject: 'Long' and 'double' value comparing problem in drools 5.1.0
My guess would be that the double is being typecast into a long before the comparison is
made?
Try switching the logic round so you do dbl < lo
Thomas
From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On
Behalf Of Miles Wen
Sent: 04 March 2011 02:59
To: rules-users(a)lists.jboss.org
Subject: [rules-users] 'Long' and 'double' value comparing problem in
drools 5.1.0
hi there,
I have a simple fact class:
public class Msg {
private Long lo = 5l;
private double dbl = 5.5;
public Long getLo() {
return lo;
}
public void setLo(Long lo) {
this.lo = lo;
}
public double getDbl() {
return dbl;
}
public void setDbl(double dbl) {
this.dbl = dbl;
}
}
and a simple drl program:
package com.sample
import com.sample.Msg;
rule "Hello World"
when
m:Msg(lo >= dbl)
then
System.out.println( "hello world" );
System.out.println(m.getLo());
System.out.println(m.getDbl());
end
I simply compare the Long value, which is 5, to the double value ,which is 5.5, with
operator '>=', and the output is:
hello world
5
5.5
but it can't be ,cause 5 is less than 5.5.
then I modified the drl program a bit:
m:Msg(lo == dbl)
It successfully prints out the message as well.It seems that drools treated the double
value '5.5' as '5' in comparing...
Is this a bug or something?What could I do to correct it?
thanks.
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7:26 a.m.
Hello pf_miles,
As far as I discovered (no documentation found), Drools' casting mechanism
seems to be different from Java's casting: *the second operator ist cast to
the typeof the first one*, independently of which one is longer or shorter.
When I turned the test around, writing
"when m:Msg(dbl <= lo)"
instead of
"when m:Msg(lo >= dbl)"
everything worked out fine for me.
Heinrich_Puschmann
--
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5049
days inactive
5049
days old
2 comments
3 participants
participants (3)
-
Heinrich_Puschmann -
Miles Wen -
Swindells, Thomas