1:05 a.m.
Hi everybody
I have read with attention the drools expert documentation, which was
very interesting, but a little 'too simple". For example, most
examples don't present rules with the keyword "forall". I also met big
difficulties mixing the references on the objects to my javacode. This
is why I would need some more documentation with examples that go
deeper into drools capacities.
To give you clues about my plan, here is an example (which works
perfectly in drools 5) that I have developed:
java code - http://drools.pastebin.com/m1a705614
rule code - http://drools.pastebin.com/m3f30cbdc
As you can see I am studying the case where drools is used for the
monitoring of a network of equipments that send alarms about their
problems. But I have big difficulties, because I would like to get
references on the objects of the "forall", and to execute javacode
such as $toto.method($titi, $tata), but such things seems impossible
(systematic failed of compilation)
Could you please help me?
Thank you very much!
Aldian
4:21 a.m.
Hi Aldian,
I think you misunderstood the semantics of forall(). Forall in Drools is
the same forall quantifier from the First Order Logic.
http://en.wikipedia.org/wiki/First-order_logic
So, if you want to write a rule that says: "When for all equipments of
type 'router' there is an alarm, then raise a general failure alarm".
when
forall( $e : Equipment( type == "router" )
Alarm( source == $e ) )
then
// raise a general failure alarm
end
So, if you have 10 routers in the working memory and only 9 of them have
associated alarms, this rule will NOT fire, because the condition is not
matched. But, if an alarm is raised for the 10th router, then all of them
have an associated alarm and the rule will fire.
So, as you can see, "forall" is a quantifier CE, in the same way that
"not" and "exists" are quantifiers. They operate on multiple facts at
once,
and as so, you can not use the variables bound inside their scope outside of
it. In the above example, if you tried to use $e in the consequence, which
of the 10 routers would it be bound to? So, since it makes no sense, the
engine disallow the usage of variables bound inside quantifiers outside of
them.
Just to be easier to remember I call quantifier CEs "scope delimiters".
The general rule is: variables bound inside a scope delimiter are never
available outside of them.
I don't understand what you are trying to do in your first rule in your
example. If you write your rule in plain English, the people from the list
can help you write it correctly.
Finally, just for completeness, be careful with the semantics of time.
Your Alarm class is using the system clock to define timeout, and that will
give you all kinds of headaches, not to mention wrong/unexpected results.
But this e-mail is already too long. I suggest you take a look at the Drools
Fusion docs on temporal reasoning.
[]s
Edson
2009/7/10 Gab Aldian <aldian.gp(a)gmail.com>
Hi everybody
I have read with attention the drools expert documentation, which was
very interesting, but a little 'too simple". For example, most
examples don't present rules with the keyword "forall". I also met big
difficulties mixing the references on the objects to my javacode. This
is why I would need some more documentation with examples that go
deeper into drools capacities.
To give you clues about my plan, here is an example (which works
perfectly in drools 5) that I have developed:
java code - http://drools.pastebin.com/m1a705614
rule code - http://drools.pastebin.com/m3f30cbdc
As you can see I am studying the case where drools is used for the
monitoring of a network of equipments that send alarms about their
problems. But I have big difficulties, because I would like to get
references on the objects of the "forall", and to execute javacode
such as $toto.method($titi, $tata), but such things seems impossible
(systematic failed of compilation)
Could you please help me?
Thank you very much!
Aldian
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
6:28 p.m.
2009/7/10, Edson Tirelli <tirelli(a)post.com>:
Hi Aldian,
I think you misunderstood the semantics of forall(). Forall in Drools is
the same forall quantifier from the First Order Logic.
http://en.wikipedia.org/wiki/First-order_logic
So, if you want to write a rule that says: "When for all equipments of
type 'router' there is an alarm, then raise a general failure alarm".
when
forall( $e : Equipment( type == "router" )
Alarm( source == $e ) )
then
// raise a general failure alarm
end
So, if you have 10 routers in the working memory and only 9 of them have
associated alarms, this rule will NOT fire, because the condition is not
matched. But, if an alarm is raised for the 10th router, then all of them
have an associated alarm and the rule will fire.
So, as you can see, "forall" is a quantifier CE, in the same way that
"not" and "exists" are quantifiers. They operate on multiple facts at
once,
and as so, you can not use the variables bound inside their scope outside of
it. In the above example, if you tried to use $e in the consequence, which
of the 10 routers would it be bound to? So, since it makes no sense, the
engine disallow the usage of variables bound inside quantifiers outside of
them.
Hello, and Thank you very much for the answer. But your explanation
shows that my understanding of this keyword was correct. And what if I
want to ewecute this condition/consequence:
When
* All routers which index is different from 0 are raising the alarm 45
then
* Execute some specific code on all these routers
end
As you can see If I attribute a $e to the routers from the condition,
it makes sense hoping to retrieve a reference on these routers to
execute code on them. I think I will escape this problem doing it with
two rules:
rule "all routers but the root raise 45"
When
* All routers which index is different from 0 are raising the alarm 45
then
* write somewhere that rule "all routers but the root raise 45"
has been validated
end
rule "set routers about the alarm 45"
When
* there is written somewhere that "all routers but the root raise
45" has been validated
* $a : Alarm is raising 45 from an equipement $e different from root
then
* execute some specific code on $a and $e
end
There is also the possibility to do it in only one rule, but I have
some doubts about time optimization:
rule "detect and set routers different from root for alarm 45"
When
* All routers which index is different from 0 are raising the alarm 45
* There is an alarm $a of numero 45 raised by an equipement $e
different from the root
Then
* execute some specific code on ($a,$e)
end
this way, drools will proceed to two verifications:
* if forall routers which index is different from 0, they have raised
an alarm of numero 45
* if any alarm $a originated from a routers $e different from the
root, is of numero 45 and then execute some code on it.
Just to be easier to remember I call quantifier CEs "scope delimiters".
The general rule is: variables bound inside a scope delimiter are never
available outside of them.
I don't understand what you are trying to do in your first rule in your
example. If you write your rule in plain English, the people from the list
can help you write it correctly.*
I am sorry, English is not my mother language, but I hope you will
understand a lot. I will know give further explanations on my example:
I am supervising a network of equipements. They are not all routers,
and actually, they are very different from each others, but you can
consider them as routers, it doesn't matter. There is a central
equipement, the root, which centralized all the alarms sent by the
other equipements. And there is a software that supervise that root
equipment and that folow me the alarms. I am trying to make
correlation on some basic cases as this one:
* for all equipements but the root I have the alarm "impossible to
connect". It is a very common alarm, because we often work with
virtual equipements, so we know that when we have that alarm on every
equipement but the root, there is no worry to have. But we would like
to suppress all that alarms that are all the same to only one that
agregate all the others. So what we wish to do is the folowing:
when
* For all equipement different from the root an alarm of type 45
as been raised,
then
* Suppress all these alarms and create an alarm that agregate all
these alarms in only one
end
As you can see the ideal would be that the forall allow to attribute
to a $tabarray variable an Array of type Alarm [] containing all the
alarms meeting the requirement.
Finally, just for completeness, be careful with the semantics of time.
Your Alarm class is using the system clock to define timeout, and that will
give you all kinds of headaches, not to mention wrong/unexpected results.
I suppose you say this because of the risk of unsynchronized clocks on
the network? But for now I don't see how to improve that...
But this e-mail is already too long. I suggest you take a look at the
Drools
Fusion docs on temporal reasoning.
Thank you very much, I will take a look about this
Regards
Aldian
2009/7/10 Gab Aldian <aldian.gp(a)gmail.com>
> Hi everybody
>
> I have read with attention the drools expert documentation, which was
> very interesting, but a little 'too simple". For example, most
> examples don't present rules with the keyword "forall". I also met big
> difficulties mixing the references on the objects to my javacode. This
> is why I would need some more documentation with examples that go
> deeper into drools capacities.
>
>
> To give you clues about my plan, here is an example (which works
> perfectly in drools 5) that I have developed:
> java code - http://drools.pastebin.com/m1a705614
> rule code - http://drools.pastebin.com/m3f30cbdc
>
> As you can see I am studying the case where drools is used for the
> monitoring of a network of equipments that send alarms about their
> problems. But I have big difficulties, because I would like to get
> references on the objects of the "forall", and to execute javacode
> such as $toto.method($titi, $tata), but such things seems impossible
> (systematic failed of compilation)
>
> Could you please help me?
>
> Thank you very much!
>
> Aldian
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
11:15 p.m.
Aldian,
Yes, this is the way to go:
rule "detect and set routers different from root for alarm 45"
When
* All routers which index is different from 0 are raising the alarm 45
* There is an alarm $a of numero 45 raised by an equipement $e
different from the root
Then
* execute some specific code on ($a,$e)
end
It would be like this:
when
forall( $e1 : Equipment( index != 0 )
Alarm( origin == $e1.name, probablecause == 45 ) )
$e2 : Equipment( index != 0 )
$a2 : Alarm( origin == $e.name, probablecause == 45 )
then
// do something with $e2 and $a2
end
The beauty of Rete is that although you are writing constraints like
"index != 0" and "probablecause == 45" twice in the rule, the engine
will
optimize and share them, effectively executing them only once for each fact.
Performance will be very good.
Just be careful with what you do in the consequence, because if for
instance you remove $a2, the forall in the rule will immediately become
false, and all subsequent activations will be canceled.
The above is the preferred way of dealing with multiple facts of the same
type, with the rule firing once for each pair ($e2, $a2), but If you want to
gather a set of them all at once, you can use accumulate and collect CEs.
Check the manual.
Regarding the system clock, the problem is that the clock is not a fact
inside the engine, but you are using it to do your reasoning. Meaning it is
changing, but the engine does not know that.
In Drools 5 we implement temporal reasoning and the concept of session
clock. This makes your reasoning process safe, correct and also allows
reproducibility and auditability.
[]s
Edson
2009/7/15 Gab Aldian <aldian.gp(a)gmail.com>
2009/7/10, Edson Tirelli <tirelli(a)post.com>:
> Hi Aldian,
>
> I think you misunderstood the semantics of forall(). Forall in Drools
is
> the same forall quantifier from the First Order Logic.
>
> http://en.wikipedia.org/wiki/First-order_logic
>
> So, if you want to write a rule that says: "When for all equipments of
> type 'router' there is an alarm, then raise a general failure alarm".
>
> when
> forall( $e : Equipment( type == "router" )
> Alarm( source == $e ) )
> then
> // raise a general failure alarm
> end
>
> So, if you have 10 routers in the working memory and only 9 of them
have
> associated alarms, this rule will NOT fire, because the condition is not
> matched. But, if an alarm is raised for the 10th router, then all of them
> have an associated alarm and the rule will fire.
>
> So, as you can see, "forall" is a quantifier CE, in the same way that
> "not" and "exists" are quantifiers. They operate on multiple
facts at
once,
> and as so, you can not use the variables bound inside their scope outside
of
> it. In the above example, if you tried to use $e in the consequence,
which
> of the 10 routers would it be bound to? So, since it makes no sense, the
> engine disallow the usage of variables bound inside quantifiers outside
of
> them.
Hello, and Thank you very much for the answer. But your explanation
shows that my understanding of this keyword was correct. And what if I
want to ewecute this condition/consequence:
When
* All routers which index is different from 0 are raising the alarm 45
then
* Execute some specific code on all these routers
end
As you can see If I attribute a $e to the routers from the condition,
it makes sense hoping to retrieve a reference on these routers to
execute code on them. I think I will escape this problem doing it with
two rules:
rule "all routers but the root raise 45"
When
* All routers which index is different from 0 are raising the alarm 45
then
* write somewhere that rule "all routers but the root raise 45"
has been validated
end
rule "set routers about the alarm 45"
When
* there is written somewhere that "all routers but the root raise
45" has been validated
* $a : Alarm is raising 45 from an equipement $e different from root
then
* execute some specific code on $a and $e
end
There is also the possibility to do it in only one rule, but I have
some doubts about time optimization:
rule "detect and set routers different from root for alarm 45"
When
* All routers which index is different from 0 are raising the alarm 45
* There is an alarm $a of numero 45 raised by an equipement $e
different from the root
Then
* execute some specific code on ($a,$e)
end
this way, drools will proceed to two verifications:
* if forall routers which index is different from 0, they have raised
an alarm of numero 45
* if any alarm $a originated from a routers $e different from the
root, is of numero 45 and then execute some code on it.
>
> Just to be easier to remember I call quantifier CEs "scope
delimiters".
> The general rule is: variables bound inside a scope delimiter are never
> available outside of them.
>
> I don't understand what you are trying to do in your first rule in
your
> example. If you write your rule in plain English, the people from the
list
> can help you write it correctly.*
I am sorry, English is not my mother language, but I hope you will
understand a lot. I will know give further explanations on my example:
I am supervising a network of equipements. They are not all routers,
and actually, they are very different from each others, but you can
consider them as routers, it doesn't matter. There is a central
equipement, the root, which centralized all the alarms sent by the
other equipements. And there is a software that supervise that root
equipment and that folow me the alarms. I am trying to make
correlation on some basic cases as this one:
* for all equipements but the root I have the alarm "impossible to
connect". It is a very common alarm, because we often work with
virtual equipements, so we know that when we have that alarm on every
equipement but the root, there is no worry to have. But we would like
to suppress all that alarms that are all the same to only one that
agregate all the others. So what we wish to do is the folowing:
when
* For all equipement different from the root an alarm of type 45
as been raised,
then
* Suppress all these alarms and create an alarm that agregate all
these alarms in only one
end
As you can see the ideal would be that the forall allow to attribute
to a $tabarray variable an Array of type Alarm [] containing all the
alarms meeting the requirement.
>
> Finally, just for completeness, be careful with the semantics of
time.
> Your Alarm class is using the system clock to define timeout, and that
will
> give you all kinds of headaches, not to mention wrong/unexpected results.
I suppose you say this because of the risk of unsynchronized clocks on
the network? But for now I don't see how to improve that...
> But this e-mail is already too long. I suggest you take a look at the
Drools
> Fusion docs on temporal reasoning.
Thank you very much, I will take a look about this
Regards
Aldian
>
> 2009/7/10 Gab Aldian <aldian.gp(a)gmail.com>
>
>> Hi everybody
>>
>> I have read with attention the drools expert documentation, which was
>> very interesting, but a little 'too simple". For example, most
>> examples don't present rules with the keyword "forall". I also met
big
>> difficulties mixing the references on the objects to my javacode. This
>> is why I would need some more documentation with examples that go
>> deeper into drools capacities.
>>
>>
>> To give you clues about my plan, here is an example (which works
>> perfectly in drools 5) that I have developed:
>> java code - http://drools.pastebin.com/m1a705614
>> rule code - http://drools.pastebin.com/m3f30cbdc
>>
>> As you can see I am studying the case where drools is used for the
>> monitoring of a network of equipments that send alarms about their
>> problems. But I have big difficulties, because I would like to get
>> references on the objects of the "forall", and to execute javacode
>> such as $toto.method($titi, $tata), but such things seems impossible
>> (systematic failed of compilation)
>>
>> Could you please help me?
>>
>> Thank you very much!
>>
>> Aldian
>> _______________________________________________
>> rules-users mailing list
>> rules-users(a)lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>
>
>
> --
> Edson Tirelli
> JBoss Drools Core Development
> JBoss by Red Hat @ www.jboss.com
>
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
11:33 p.m.
2009/7/15 Edson Tirelli <tirelli(a)post.com>:
Aldian,
Yes, this is the way to go:
rule "detect and set routers different from root for alarm 45"
When
* All routers which index is different from 0 are raising the alarm 45
* There is an alarm $a of numero 45 raised by an equipement $e
different from the root
Then
* execute some specific code on ($a,$e)
end
It would be like this:
when
forall( $e1 : Equipment( index != 0 )
Alarm( origin == $e1.name, probablecause == 45 ) )
$e2 : Equipment( index != 0 )
$a2 : Alarm( origin == $e2.name, probablecause == 45 )
then
// do something with $e2 and $a2
end
What happens if the RHS contains a retract( $a2 ), which (I think) is
one of the things Aldian intends to do?
Also, there is the requirement of inserting a summary alarm
replacing all the 45ers on non-root equipments. You may not
want to do this on the RHS, unless you rely on the engine
discarding fact duplicates.
-W
12:25 a.m.
Well, I was going to suggest how to do it, but I guess it is a nice
exercise for the avid users. :)
Submit your suggestions to the list people. Lets see what you come up
with. It can be implemented as a single rule or as multiple rules. I will
send my own suggestion to the list for critics tomorrow.
Rule spec:
"When there is an alarm with probable cause 45 for each and every one of the
monitored equipments in the network, except the equipment whose index is 0
(zero, i.e. non root equiment), discard all the corresponding alarms and
replace them by a single, consolidated alarm."
For simplicity, people can use pseudo code in the RHS if they prefer.
The LHS of the rule (or rules) is what matters the most for us. The above
spec has still some ambiguities, so feel free to interpret them as you like
or suggest modifications.
Any takers? ;)
Cheers,
Edson
2009/7/15 Wolfgang Laun <wolfgang.laun(a)gmail.com>
2009/7/15 Edson Tirelli <tirelli(a)post.com>:
>
> Aldian,
>
> Yes, this is the way to go:
>
> rule "detect and set routers different from root for alarm 45"
> When
> * All routers which index is different from 0 are raising the alarm 45
> * There is an alarm $a of numero 45 raised by an equipement $e
> different from the root
> Then
> * execute some specific code on ($a,$e)
> end
>
> It would be like this:
>
> when
> forall( $e1 : Equipment( index != 0 )
> Alarm( origin == $e1.name, probablecause == 45 ) )
> $e2 : Equipment( index != 0 )
> $a2 : Alarm( origin == $e2.name, probablecause == 45 )
> then
> // do something with $e2 and $a2
> end
>
What happens if the RHS contains a retract( $a2 ), which (I think) is
one of the things Aldian intends to do?
Also, there is the requirement of inserting a summary alarm
replacing all the 45ers on non-root equipments. You may not
want to do this on the RHS, unless you rely on the engine
discarding fact duplicates.
-W
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
12:52 a.m.
2009/7/15, Wolfgang Laun <wolfgang.laun(a)gmail.com>:
2009/7/15 Edson Tirelli <tirelli(a)post.com>:
>
> Aldian,
>
> Yes, this is the way to go:
>
> rule "detect and set routers different from root for alarm 45"
> When
> * All routers which index is different from 0 are raising the alarm 45
> * There is an alarm $a of numero 45 raised by an equipement $e
> different from the root
> Then
> * execute some specific code on ($a,$e)
> end
>
> It would be like this:
>
> when
> forall( $e1 : Equipment( index != 0 )
> Alarm( origin == $e1.name, probablecause == 45 ) )
> $e2 : Equipment( index != 0 )
> $a2 : Alarm( origin == $e2.name, probablecause == 45 )
> then
> // do something with $e2 and $a2
> end
>
What happens if the RHS contains a retract( $a2 ), which (I think) is
one of the things Aldian intends to do?
Also, there is the requirement of inserting a summary alarm
replacing all the 45ers on non-root equipments. You may not
want to do this on the RHS, unless you rely on the engine
discarding fact duplicates.
Thank you for your answers. I am currently examining how to use the
accumulate keyword. As for the alarms that have been correlated in
only one, I don't know how they are dealt with commonly, but here are
the problems we have seen:
1) In the hypothesis where a same single alarm could be correlated
with different pairs to create correlated alarms in different cases,
it would be careless to retract it after having been correlated one
time, because it would block all further correlation
2) In the hypothesis where a correlated alarm sum of a lot of single
one has been created and where an event is raised to tell that one of
these alarms has fallen: Two possibilities: Introducing the notion of
"correlated alarm partially cleared" or removing the correlated alarm
and reintroducing its remaining components. If the correlation has
been well done, it doesn't make sense to use the first possibility,
because once the condition are no longer validated, there is no reason
to display the correlated alarm any further.
Here is the way we will deal with this: Currently there are two list
of alarms in main class:
a) the list of alarms that has been inserted to drools (including
single and correlated ones) but not cleared yet
b) the list of alarms that should be displayed to the operator.
So basically, when we decide that a group of alarms should be
correlated in only one, we remove them from the list (b) and we add to
(a) and (b) a correlated one that contains all the group. When an
event rise to signal that one alarm is no longer raised, all
correlated alarms it is part of are destroyed and removed from both
lists and all their components except the fallen one are re-added to
list b. The mechanisms allowing this are based on the alarm keys that
are unique and on some mappings.
So as you see there is a distinction between what is in drools, and
what is visible by the operator. All non cleared alarms (single and
correlated) are permanently in drools until it is destroyed because it
has been cleared. The only inconvenient is then to avoid the rules to
fire indefinitely, since they are permanently susceptible to be
validated. To avoid this all rules are of type "If some alarms respect
the folowing conditions and at least one of them is not part of a
correlated alarm built for this rule, then...". There are probably
smarter ways to do, but this is my point of view for the moment.
Cheers
Aldian
5:55 p.m.
I finally suceeded to get what I wanted using the keyword accumulate
which is really very poweful as said in the doc. Here is the rule:
http://drools.pastebin.com/m4f938e40
It is a little bit complex, but it perfectly works. The only
observation I have is that it seems drools compatible jdk is < 1.5,
since I tryed to declare my linkedlist this way: LinkedList<Alarm>(),
but got warnings about the unexpected '<'. One other thing, the
"implicit and" does not work in the accumulate, you have to put it
clearly.
Now I have something giving me the list I need, all should be easy I
think. Do you have any observation on the way I did it?
Cheers
Aldian
6:27 p.m.
accumulate is indeed complex; the simpler collect might be applicable
as well in this case.
rule all45_A
when
forall ( Equipment( parent == 0, $id : id )
Alarm( cause == 45, source == $id ) )
$alarms : ArrayList()
from collect( Alarm( cause == 45, $source : source ) )
then
for( Object o: $alarms ){
retract( o ); // or anything else with (Alarm)o
}
insert( new SummaryAlarm( 45 ) );
end
Another solution would be by using 2 rules:
rule all45_B1
when
forall ( Equipment( parent == 0, $id : id )
Alarm( cause == 45, source == $id ) )
then
insert( new SummaryAlarm( 45 ) );
end
rule all45_B2
when
SummaryAlarm( $cause : cause )
$a : Alarm( cause == $cause, $source : source )
Equipment( parent == 0, id == $source)
then
retract( $a ); // or anything else with $a
end
-W
On Thu, Jul 16, 2009 at 10:55 AM, Gab Aldian<aldian.gp(a)gmail.com> wrote:
I finally suceeded to get what I wanted using the keyword accumulate
which is really very poweful as said in the doc. Here is the rule:
http://drools.pastebin.com/m4f938e40
It is a little bit complex, but it perfectly works. The only
observation I have is that it seems drools compatible jdk is < 1.5,
since I tryed to declare my linkedlist this way: LinkedList<Alarm>(),
but got warnings about the unexpected '<'. One other thing, the
"implicit and" does not work in the accumulate, you have to put it
clearly.
Now I have something giving me the list I need, all should be easy I
think. Do you have any observation on the way I did it?
Cheers
Aldian
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
http://lists.jboss.org/mailman/listinfo/rules-users
9:40 p.m.
After some more investigation, I managed also to make it work with
collect: http://drools.pastebin.com/m14f0e329
I would rather not multiplicate rules, because we probably will have
dozens for our system which is very big and can supervise around a
thousand equipements in some cases
Thank you very much for the advices
Aldian
10:34 p.m.
Very good! :)
Just FYI, in the case of accumulate, you could also use the collectList()
function to simplify your rule. This:
$alarmList : LinkedList()
from accumulate ( ($e : Element(parentindex!=0) and
$a : Alarm( origin matches
$e.name&& probablecause==45)),
init( LinkedList alarmList = new
LinkedList();),
action( alarmList.add($a);),
reverse( alarmList.remove($a);),
result( alarmList ) );
Is the same as:
$alarmList : List()
from accumulate ( ($e : Element(parentindex!=0) and
$a : Alarm( origin matches
$e.name&& probablecause==45)),
collectList( $a ) );
Also, you can always implement your own functions for accumulate:
http://blog.athico.com/2009/06/how-to-implement-accumulate-functions.html
Finally, I see you are using "matches" operator to compare equal strings.
Not sure if that is what you want, because "==" has different semantics and
better performance than "matches" if what you really want is compare
equality. Remember that in regexps, some characters have special meaning,
for instance, "." is a wildcard for any character. Meaning:
"abc" matches "a.c" -> true
"abc" == "a.c" -> false
Cheers,
Edson
2009/7/16 Gab Aldian <aldian.gp(a)gmail.com>
After some more investigation, I managed also to make it work with
collect: http://drools.pastebin.com/m14f0e329
I would rather not multiplicate rules, because we probably will have
dozens for our system which is very big and can supervise around a
thousand equipements in some cases
Thank you very much for the advices
Aldian
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
http://lists.jboss.org/mailman/listinfo/rules-users
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
11:04 p.m.
Thank you very much for the precision, I didn't see that. I used
'matches' instead of '==', because using '==' for comparing
Strings in
java is very unsafe since it compares the references and not the
content of the strings. I thought it was the same in drools and I
thought 'matches' was the equivalent of the java '.equals' method.
But now you mention that in drools '==' is correct, I will use it rather.
Aldian
2009/7/16, Edson Tirelli <tirelli(a)post.com>:
Very good! :)
Just FYI, in the case of accumulate, you could also use the collectList()
function to simplify your rule. This:
$alarmList : LinkedList()
from accumulate ( ($e : Element(parentindex!=0) and
$a : Alarm( origin matches
$e.name&& probablecause==45)),
init( LinkedList alarmList = new
LinkedList();),
action( alarmList.add($a);),
reverse( alarmList.remove($a);),
result( alarmList ) );
Is the same as:
$alarmList : List()
from accumulate ( ($e : Element(parentindex!=0) and
$a : Alarm( origin matches
$e.name&& probablecause==45)),
collectList( $a ) );
Also, you can always implement your own functions for accumulate:
http://blog.athico.com/2009/06/how-to-implement-accumulate-functions.html
Finally, I see you are using "matches" operator to compare equal strings.
Not sure if that is what you want, because "==" has different semantics and
better performance than "matches" if what you really want is compare
equality. Remember that in regexps, some characters have special meaning,
for instance, "." is a wildcard for any character. Meaning:
"abc" matches "a.c" -> true
"abc" == "a.c" -> false
Cheers,
Edson
2009/7/16 Gab Aldian <aldian.gp(a)gmail.com>
> After some more investigation, I managed also to make it work with
> collect: http://drools.pastebin.com/m14f0e329
>
> I would rather not multiplicate rules, because we probably will have
> dozens for our system which is very big and can supervise around a
> thousand equipements in some cases
>
> Thank you very much for the advices
>
> Aldian
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> http://lists.jboss.org/mailman/listinfo/rules-users
>
--
Edson Tirelli
JBoss Drools Core Development
JBoss by Red Hat @ www.jboss.com
6:33 p.m.
New subject: Problems with persistence of drools-flow
I have a simple flow with human task and I want to persist it into database. I'm using
MSSQL DB.
My code is like this:
KnowledgeBase kbase = readKnowledgeBase();
// create the entity manager factory and register it in the environment
EntityManagerFactory emf =
Persistence.createEntityManagerFactory( "org.drools.persistence.jpa" );
Environment env = KnowledgeBaseFactory.newEnvironment();
env.set( EnvironmentName.ENTITY_MANAGER_FACTORY, emf );
BitronixTransactionManager btm = TransactionManagerServices.getTransactionManager();
env.set( EnvironmentName.TRANSACTION_MANAGER, btm);
StatefulKnowledgeSession ksession =
JPAKnowledgeService.newStatefulKnowledgeSession( kbase, null, env );
KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory.newFileLogger(ksession,
"test");
ksession.getWorkItemManager().registerWorkItemHandler("Human Task", new
WSHumanTaskHandler());
// start a new process instance
Map<String,Object> data = new HashMap<String,Object>();
data.put("data3", new MyTask(1,"This is taks 1"));
ProcessInstance pi = ksession.startProcess("com.sample.ruleflow",data);
logger.close();
But when i run it, it end up with this error and there is nothing in the database (the
tables were created, but there are all empty):
java.lang.NullPointerException
at
org.drools.persistence.processinstance.ProcessInstanceInfo.getId(ProcessInstanceInfo.java:70)
at
org.drools.persistence.processinstance.JPAProcessInstanceManager.addProcessInstance(JPAProcessInstanceManager.java:34)
at org.drools.common.AbstractWorkingMemory.startProcess(AbstractWorkingMemory.java:1620)
at org.drools.process.command.StartProcessCommand.execute(StartProcessCommand.java:46)
at org.drools.process.command.StartProcessCommand.execute(StartProcessCommand.java:10)
at
org.drools.persistence.session.SingleSessionCommandService.execute(SingleSessionCommandService.java:229)
at
org.drools.process.command.impl.CommandBasedStatefulKnowledgeSession.startProcess(CommandBasedStatefulKnowledgeSession.java:163)
at com.sample.RuleFlowPersistenceTest.main(RuleFlowPersistenceTest.java:74)
java.lang.RuntimeException: Could not rollback transaction
at
org.drools.persistence.session.SingleSessionCommandService.execute(SingleSessionCommandService.java:258)
at
org.drools.process.command.impl.CommandBasedStatefulKnowledgeSession.startProcess(CommandBasedStatefulKnowledgeSession.java:163)
at com.sample.RuleFlowPersistenceTest.main(RuleFlowPersistenceTest.java:74)
Caused by: java.lang.RuntimeException: Could not execute command
at
org.drools.persistence.session.SingleSessionCommandService.execute(SingleSessionCommandService.java:255)
... 2 more
Caused by: java.lang.NullPointerException
at
org.drools.persistence.processinstance.ProcessInstanceInfo.getId(ProcessInstanceInfo.java:70)
at
org.drools.persistence.processinstance.JPAProcessInstanceManager.addProcessInstance(JPAProcessInstanceManager.java:34)
at org.drools.common.AbstractWorkingMemory.startProcess(AbstractWorkingMemory.java:1620)
at org.drools.process.command.StartProcessCommand.execute(StartProcessCommand.java:46)
at org.drools.process.command.StartProcessCommand.execute(StartProcessCommand.java:10)
at
org.drools.persistence.session.SingleSessionCommandService.execute(SingleSessionCommandService.java:229)
... 2 more
In JPAProcessInstanceManager.java there this method is called:
public void addProcessInstance(ProcessInstance processInstance) {
ProcessInstanceInfo processInstanceInfo = new ProcessInstanceInfo( processInstance
);
EntityManager em = (EntityManager) this.workingMemory.getEnvironment().get(
EnvironmentName.ENTITY_MANAGER );
em.persist( processInstanceInfo );
((ProcessInstance) processInstance).setId( processInstanceInfo.getId() );
processInstanceInfo.updateLastReadDate();
internalAddProcessInstance(processInstance);
}
But em.persist does nothing, no connection do DB is called. And then the next line will
fail.
Can anybody help me.
Thanks
Martin Sevcik
5409
days inactive
5415
days old
12 comments
4 participants
participants (4)
-
Edson Tirelli -
Gab Aldian -
Wolfgang Laun -
Ševčík Martin