5:59 p.m.
You must either update an existing working memory object or insert a new working memory
object with the results. That's how rules communicate with each other.
GreG
On Aug 12, 2010, at 10:31 AM, Manav <manav7574(a)yahoo.com> wrote:
Hi,
I am using the version 5.x of drools and i have a scenario where i want to hold
the result of
a test in one rule to a temperory variable . This result will then be used in
another rule that will be fired
later in the sequence .
For ex :
salience 100
when
User (language.keySet contains "Japanese", $j_score :
language["Japanese"])
then
// do something
end
salience 50
when
User (language.keySet contains "French", $f_score :
language["French"])
then
// do something
end
salience 25
when
eval (($j_score + $f_score) > 4)
then
// update the same to db
end
Is this possible in Drools 5.x ?
Regards,
Manav
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users
4:34 a.m.
New subject: Caching results in temperory variables
Thanks for your response Greg. As you said this is what i tried to fix the issue
by creating a UserResult obj that has score as a property and inserting the same
in working memory. I update the results in subsequent rules in the "then"
clause. There are some issues that i faced in this as well :-
-- In my last rule if i want to do a check on score property of my result
object in the "when" clause the score has not been updated .
-- however if i do the same check in the "then" clause it seems to work
properly.
-- I tried to overcome by doing an update in one of my rules to check if that
would work. That however went into an infinite loop. So i used the
"lock-on-active true" property . However it seemed to work well for only the
first user object and doesn't work for other user objects that are loaded later.
Below is the sample rule file . If the scenario is not clear pls do let me know
and i will send across the different drls as attachments .
salience 200
when
User ($id : id)
then
UserResult urslt = new UserResult ($id);
insert ($id)
end
salience 100
lock-on-active truewhen
$usr : User (language.keySet contains "Japanese", $j_score :
language["Japanese"])
$urslt : UserResult (id == $usr.id)
then
$usrlt.setLangScore("Japanese", $j_score);
end
salience 50
lock-on-active truewhen
User (language.keySet contains "French", $f_score :
language["French"])
$urslt : UserResult (id == $usr.id)
then
$usrlt.setLangScore("French", $_score);
update ($usrlt);
end
salience 25
when
UserResult (score > 4) // does not work
then
// if ($usr_rslt.getScore() > 4) --> works well
// update the db
end
Regards,
Manav
----- Original Message ----
From: Greg Barton <greg_barton(a)yahoo.com>
To: Manav <manav7574(a)yahoo.com>; Rules Users List
<rules-users(a)lists.jboss.org>
Sent: Thu, August 12, 2010 9:29:28 PM
Subject: Re: [rules-users] Caching results in temperory variables
You must either update an existing working memory object or insert a new working
memory object with the results. That's how rules communicate with each other.
GreG
On Aug 12, 2010, at 10:31 AM, Manav <manav7574(a)yahoo.com> wrote:
Hi,
I am using the version 5.x of drools and i have a scenario where i want to hold
the result of
a test in one rule to a temperory variable . This result will then be used in
another rule that will be fired
later in the sequence .
For ex :
salience 100
when
User (language.keySet contains "Japanese", $j_score :
language["Japanese"])
then
// do something
end
salience 50
when
User (language.keySet contains "French", $f_score :
language["French"])
then
// do something
end
salience 25
when
eval (($j_score + $f_score) > 4)
then
// update the same to db
end
Is this possible in Drools 5.x ?
Regards,
Manav
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users
10:07 a.m.
New subject: Caching results in temperory variables
See inline annotations.
On 13 August 2010 04:34, Manav <manav7574(a)yahoo.com> wrote:
lock-on-active truewhen
> $usr : User (language.keySet contains "Japanese", $j_score :
> language["Japanese"])
I prefer to add a binding of User's id: User( $id == id )
> $urslt : UserResult (id == $usr.id)
so I can simplify this. Add a constraint to avoid looping:
$urslt : USerResult( id == $id, langScore.keySet not contains
"Japanese" )
> then
> $usrlt.setLangScore("Japanese", $j_score);
update( $usrlt );
> end
rule "FrenchScore"
> salience 50
Why not 100?
Same as before:
$urslt : UserResult (id == $id <http://usr.id/>;, langScore.keySet not
contains "French" )
then
> $usrlt.setLangScore("French", $_score);
> update ($usrlt);
> end
> salience 25
> when
> UserResult (score > 4) // does not work
> then
> // if ($usr_rslt.getScore() > 4) --> works well
> // update the db
> end
> Regards,
> Manav
The repetition of rules JapanesScore and FrenchScore could be avoided by
inserting static objects
insert( new Language( "Japanese" ) );
insert( new Language( "French" ) );
// more of the same
rule "PolyglottScore"
salience 100
when
Language( $name : name )
User ($id : id, language.keySet contains $name", $f_score :
language[$name])
$urslt : UserResult (id == $id <http://usr.id/>;, langScore.keySet not
contains $name )
then
modify( $usrlt ){
setLangScore($name, $_score)
}
end
HTH
--W
> ----- Original Message ----
> From: Greg Barton <greg_barton(a)yahoo.com > To:
Manav <manav7574(a)yahoo.com>; Rules Users List <
> rules-users(a)lists.jboss.org > Sent: Thu, August 12, 2010
9:29:28 PM
> Subject: Re: [rules-users] Caching results in temperory variables
> You must either update an existing working memory object
or insert a new
> working
> memory object with the results. That's how rules communicate with each
> other.
> GreG
> On Aug 12, 2010, at 10:31 AM, Manav
<manav7574(a)yahoo.com> wrote:
> Hi,
> I am using the version 5.x of drools and i have a scenario
where i want to
> hold
> the result of
> a test in one rule to a temperory variable . This result
will then be used
> in
> another rule that will be fired
> later in the sequence .
> For ex :
> salience 50
> when
> User (language.keySet contains "French", $f_score :
language["French"])
> then
> // do something
> end
> salience 25
> when
> eval (($j_score + $f_score) > 4)
> then
> // update the same to db
> end
> Is this possible in Drools 5.x ?
> Regards,
> Manav
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
Thanks for your response Greg. As you said this is what i tried to
fix the
issue
by creating a UserResult obj that has score as a property and inserting the
same
in working memory. I update the results in subsequent rules in the "then"
clause. There are some issues that i faced in this as well :-
-- In my last rule if i want to do a check on score property of my result
object in the "when" clause the score has not been updated .
-- however if i do the same check in the "then" clause it seems to work
properly.
-- I tried to overcome by doing an update in one of my rules to check if
that
would work. That however went into an infinite loop. So i used the
"lock-on-active true" property . However it seemed to work well for only
the
first user object and doesn't work for other user objects that are loaded
later.
Below is the sample rule file . If the scenario is not clear pls do let me
know
and i will send across the different drls as attachments .
salience 200
when
User ($id : id)
then
UserResult urslt = new UserResult ($id);
insert ($id)
Here I'd expect
insert( urslt );
Also, to be on the safe side, I always add a pattern
not( UserResult( id == $id ) )
to avoid the creation of multiple UserResult's for the same User (if there's
a minimal chance it might be modified during the following fusillade).
end
rule "JapaneseScore"
salience 100
lock-on-active true
not necessary now
> when
> User (language.keySet contains "French", $f_score :
language["French"])
> $urslt : UserResult (id == $usr.id)
salience 100
> when
> User (language.keySet contains "Japanese", $j_score :
> language["Japanese"])
> then
> // do something
> end
6:36 p.m.
New subject: Caching results in temperory variables
Your explanation is absolutely superb. I modified my drl as per your
suggestions and it's just been completely transformed. Just one question
regarding one suggestion below :
-- is this something like a for each loop in java . This is the first example i
have seen in drl
-- will this automatically iterate over as many languages as have been inserted
?
-- the inserts .. don't they have to be within a rule block ? or did you just
omit other things to keep it simple
insert( new Language( "Japanese" ) );
insert( new Language( "French" ) );
// more of the same
rule "PolyglottScore"
salience 100
when
Language( $name : name )
User ($id : id, language.keySet contains $name", $f_score : language[$name])
$urslt : UserResult (id == $id, langScore.keySet not contains $name )
then
modify( $usrlt ){
setLangScore($name, $_score)
}
end
________________________________
From: Wolfgang Laun <wolfgang.laun(a)gmail.com To: Manav
<manav7574(a)yahoo.com>; Rules Users List <rules-users(a)lists.jboss.org Sent: Fri, August 13, 2010 1:37:45 PM
Subject: Re: [rules-users] Caching results in temperory variables
See inline annotations.
On 13 August 2010 04:34, Manav <manav7574(a)yahoo.com> wrote:
Thanks for your response Greg. As you said this is what i tried to fix the issue
rule "JapaneseScore"
salience 100
lock-on-active truewhen
> $usr : User (language.keySet contains "Japanese", $j_score :
>language["Japanese"])
I prefer to add a binding of User's id: User( $id == id )
$urslt : UserResult (id == $usr.id)
so I can simplify this. Add a constraint to avoid looping:
$urslt : USerResult( id == $id, langScore.keySet not contains "Japanese"
)
then
> $usrlt.setLangScore("Japanese", $j_score);
update( $usrlt );
end
rule "FrenchScore"
salience 50
Why not 100?
lock-on-active true
not necessary now
when
> User (language.keySet contains "French", $f_score :
language["French"])
> $urslt : UserResult (id == $usr.id)
Same as before:
$urslt : UserResult (id == $id, langScore.keySet not contains "French" )
then
> $usrlt.setLangScore("French", $_score);
> update ($usrlt);
>end
>salience 25
>when
> UserResult (score > 4) // does not work
>then
> // if ($usr_rslt.getScore() > 4) --> works well
> // update the db
>end
>Regards,
>Manav
The repetition of rules JapanesScore and FrenchScore could be avoided by
inserting static objects
insert( new Language( "Japanese" ) );
insert( new Language( "French" ) );
// more of the same
rule "PolyglottScore"
salience 100
when
Language( $name : name )
User ($id : id, language.keySet contains $name", $f_score : language[$name])
$urslt : UserResult (id == $id, langScore.keySet not contains $name )
then
modify( $usrlt ){
setLangScore($name, $_score)
}
end
HTH
--W
>----- Original Message ----
>From: Greg Barton <greg_barton(a)yahoo.com >To:
Manav <manav7574(a)yahoo.com>; Rules Users List <rules-users(a)lists.jboss.org >Sent: Thu, August 12, 2010 9:29:28 PM
>Subject: Re: [rules-users] Caching results in temperory variables
>You must either update an existing working memory object or
insert a new
working
>memory object with the results. That's how rules communicate with each other.
>GreG
>On Aug 12, 2010, at 10:31 AM, Manav
<manav7574(a)yahoo.com> wrote:
>Hi,
>I am using the version 5.x of drools and i have a scenario
where i want to hold
>the result of
>a test in one rule to a temperory variable . This result
will then be used in
>another rule that will be fired
>later in the sequence .
>For ex :
>salience 100
>when
> User (language.keySet contains "Japanese", $j_score :
language["Japanese"])
>then
> // do something
>end
>salience 50
>when
> User (language.keySet contains "French", $f_score :
language["French"])
>then
> // do something
>end
>salience 25
>when
> eval (($j_score + $f_score) > 4)
>then
> // update the same to db
>end
>Is this possible in Drools 5.x ?
>Regards,
>Manav
>_______________________________________________
>rules-users mailing list
>rules-users(a)lists.jboss.org
>https://lists.jboss.org/mailman/listinfo/rules-users
>_______________________________________________
>rules-users mailing list
>rules-users(a)lists.jboss.org
>https://lists.jboss.org/mailman/listinfo/rules-users
by creating a UserResult obj that has score as a property and
inserting the
same
in working memory. I update the results in subsequent rules in the
"then"
clause. There are some issues that i faced in this as well :-
-- In my last rule if i want to do a check on score property of my result
object in the "when" clause the score has not been updated .
-- however if i do the same check in the "then" clause it seems to work
properly.
-- I tried to overcome by doing an update in one of my rules to check if that
would work. That however went into an infinite loop. So i used the
"lock-on-active true" property . However it seemed to work well for only the
first user object and doesn't work for other user objects that are loaded
later.
Below is the sample rule file . If the scenario is not clear pls do let me know
and i will send across the different drls as attachments .
salience 200
when
User ($id : id)
then
UserResult urslt = new UserResult ($id);
insert ($id)
Here I'd expect
insert( urslt );
Also, to be on the safe side, I always add a pattern
not( UserResult( id == $id ) )
to avoid the creation of multiple UserResult's for the same User (if there's a
minimal chance it might be modified during the following fusillade).
end
8:11 p.m.
New subject: Caching results in temperory variables
On 13 August 2010 18:36, Manav <manav7574(a)yahoo.com> wrote:
Your explanation is absolutely superb. I modified my drl as per
your
suggestions and it's just been completely transformed. Just one question
regarding one suggestion below :
-- is this something like a for each loop in java . This is the first
example i have seen in drl
In a way, yes. Since
Foo( ... ) # match any Foo according to constraints, if any
Bar( ... ) # match any Bar according to constraints, if any
these two patterns produce the Cartesian product, such as a nested loop
does. BUT, the order of the pairings is indeterministic, and changes in WM
might influence this loop, even make it infinitive. Therefore, "in a way".
-- will this automatically iterate over as many languages as have been
inserted ?
That's the whole idea :-)
-- the inserts .. don't they have to be within a rule block ? or
did you
just omit other things to keep it simple
You can do it in the Java application framework. You can also write a
high-salience one-shot rule such as
rule "1st shot"
when
then
insert( new Language( "Japanese" ) );
insert( new Language( "French" ) );
// more of the same
end
Cheers
Wolfgang
4:37 a.m.
New subject: Caching results in temperory variables
Great stuff. Things are very clear now . It raised some more questions though :-
-- Say we use the one shot insert at the very start of the rule. And i am using
this rule to validate some
100,000 User facts . Will these inserts be done only once or as many times
as new facts are inserted
in WM. Is there something that we can use to determine this as per the
need.
-- As done in the example below there will be as many UserResult objects
inserted in the memory as there are User facts. We insert them in the WM at the
start and update them as the rule executes . At the very end should we retract
them as well from the WM . Is that a suggested practice or doesn't really matter
.
-- Does WM automatically remove objects if they have not been used for long time
or it's the responsibility of the application developer to keep track of what's
goes in and out.
-- Instead of inserting one fact at a time if we insert a collection at one go
in the WM how does this rule get applied . Sequentially to all the objects or in
parallel ?
Regards,
Manav
________________________________
From: Wolfgang Laun <wolfgang.laun(a)gmail.com To: Manav
<manav7574(a)yahoo.com Cc: rules-users(a)lists.jboss.org
Sent: Fri, August 13, 2010 11:41:53 PM
Subject: Re: [rules-users] Caching results in temperory variables
On 13 August 2010 18:36, Manav <manav7574(a)yahoo.com> wrote:
Your explanation is absolutely superb. I modified my drl as per your
suggestions and it's just been completely transformed. Just one question
regarding one suggestion below :
You can do it in the Java application framework. You can also write a
high-salience one-shot rule such as
rule "1st shot"
when
then
insert( new Language( "Japanese" ) );
>insert( new Language( "French" ) );
>// more of the same
end
Cheers
Wolfgang
-- is this something like a for each loop in java . This is the first example i
have seen in drl
In a way, yes. Since
Foo( ... ) # match any Foo according to constraints, if any
Bar( ... ) # match any Bar according to constraints, if any
these two patterns produce the Cartesian product, such as a nested loop does.
BUT, the order of the pairings is indeterministic, and changes in WM might
influence this loop, even make it infinitive. Therefore, "in a way".
-- will this automatically iterate over as many languages as have been inserted
?
That's the whole idea :-)
-- the inserts .. don't they have to be within a rule block ? or did you just
omit other things to keep it simple
10:53 a.m.
New subject: Caching results in temperory variables
A rule only gets re-evaluated when something it depends on in it's 'when' part
is updated (or added).
Because the one shot rule doesn't depend on anything it never gets re-evaluated so
will only fire at the start.
Whether you retract them at the end depends on whether your are planning to reuse your
working memory, if you aren't planning to reuse it just dispose of the working memory
as retracting facts causes the rete graph to be re-evaluated and rules triggered as
necessary.
If you are using the standard mode then no, the working memory is just a specialised form
of database. If you are using event processing then Events will be removed when they are
no longer relevant.
Asking whether rules are applied sequentially or parallel is actually pretty meaningless,
with declarative programming such as drools you are declaring what you want to happen not
how it is achieved (as opposed to imperative programming such as java where you define the
steps to achieve something). Whether the rules are evaluated in parallel or sequentially
is just a implementation, although the actions ("then part) of the rules will be
performed serially. If you want more details I'd recommend reading up about Rete and
how drools implements it.
Thomas
From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On
Behalf Of Manav
Sent: 14 August 2010 03:38
To: Wolfgang Laun
Cc: rules-users(a)lists.jboss.org
Subject: Re: [rules-users] Caching results in temperory variables
Great stuff. Things are very clear now . It raised some more questions though :-
-- Say we use the one shot insert at the very start of the rule. And i am using this rule
to validate some
100,000 User facts . Will these inserts be done only once or as many times as new
facts are inserted
in WM. Is there something that we can use to determine this as per the need.
-- As done in the example below there will be as many UserResult objects inserted in the
memory as there are User facts. We insert them in the WM at the start and update them as
the rule executes . At the very end should we retract them as well from the WM . Is that a
suggested practice or doesn't really matter .
-- Does WM automatically remove objects if they have not been used for long time or
it's the responsibility of the application developer to keep track of what's goes
in and out.
-- Instead of inserting one fact at a time if we insert a collection at one go in the WM
how does this rule get applied . Sequentially to all the objects or in parallel ?
Regards,
Manav
________________________________
From: Wolfgang Laun <wolfgang.laun(a)gmail.com>
To: Manav <manav7574(a)yahoo.com>
Cc: rules-users(a)lists.jboss.org
Sent: Fri, August 13, 2010 11:41:53 PM
Subject: Re: [rules-users] Caching results in temperory variables
On 13 August 2010 18:36, Manav
<manav7574@yahoo.com<mailto:manav7574@yahoo.com>> wrote:
Your explanation is absolutely superb. I modified my drl as per your suggestions and
it's just been completely transformed. Just one question regarding one suggestion
below :
-- is this something like a for each loop in java . This is the first example i have seen
in drl
In a way, yes. Since
Foo( ... ) # match any Foo according to constraints, if any
Bar( ... ) # match any Bar according to constraints, if any
these two patterns produce the Cartesian product, such as a nested loop does. BUT, the
order of the pairings is indeterministic, and changes in WM might influence this loop,
even make it infinitive. Therefore, "in a way".
-- will this automatically iterate over as many languages as have been inserted ?
That's the whole idea :-)
-- the inserts .. don't they have to be within a rule block ? or did you just omit
other things to keep it simple
You can do it in the Java application framework. You can also write a high-salience
one-shot rule such as
rule "1st shot"
when
then
insert( new Language( "Japanese" ) );
insert( new Language( "French" ) );
// more of the same
end
Cheers
Wolfgang
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5010
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5014
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6 comments
4 participants
participants (4)
-
Greg Barton -
Manav -
Swindells, Thomas -
Wolfgang Laun