6.0 Alpha - Annotation Driven development with Multi Version Loading
by Mark Proctor
http://blog.athico.com/2012/12/60-alpha-annotation-driven-development.html
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Drools & jBPM 6.0 alpha should be out end of next week. 6.0 introduces convention based projects that remove the need for boiler plate code - literally just drop in the drl or bpmn2 and get going. Further we now allow rules and processes to be published as maven artifacts, in maven repositories. These artifacts can either be resolve via the classpath or downloaded dynamically on the fly. We even support out of the box side by side version loading, via the maven ReleaseId conventions.
As a little taster here is a new screenshot showing the annotation driven development. The lines below are all that's needed to dynamically load a module from a local or remote maven repository and start working with it. KieSession is the new, shorter name, for StatefulKnowlegeSession. Kie is an acronym for "Knowledge Is Everything", but I'll talk about Kie in another blog, expect to start hearing a lot about it soon :)
And here is a complete example screen shot. Create the drl, define the kmodule and start using them.
(click image to enlarge)
13 years, 2 months
Drools Planner: Solving a job schedule problem
by mr_moe
Hey,
I want to solve the following problem using drools planner:There are several
jobs which should be worked through by a machine on one day. Each job has a
length and a constraint that it only can be worked of between a fixed start
and end date.
For example there are three tasks
Job first possible start date last possible start date length
A 7:00 am 8:30 am 60 min
B 7:30 am 10:00 am 30 min
C 10:30 am 12:00 pm 60 min
The jobs should be organized in the following way, that there is as less
time between tasks as possible. If it is due to restrictions not possible to
order the tasks without a break and also the break is longer than, say, 20
minutes, the tasks should be organized with a long break as possible.Tasks
cannot overlap.
A good solution would be:
Job Start date End date
A 7:00 am 8:00 am
B 8:00 am 8:30 am
C 12:00 am 1:00 pm
First, the planning variable (ValueRangeType.FROM_PLANNING_ENTITY_PROPERTY)
of each task is its start date, which can takes a value which is between the
first possible start date and the last possible start date. E.g. possible
start dates for job A are between 7:00 am and 8:30 am. To make sure, that
tasks aren’t scheduled at the same time, I’ve written a hard constraint
rule, which checks if one task overlaps with another one. And running the
planner with hard constraints only, it works fine.
But now I’m getting problems, writing the soft constraints. At the moment,
every job (planning entity) has variables, called “nextJob” und “prevJob”,
which points to the jobs which are scheduled before and after that job. In
my example, it would look like this:
Job prevJob nextJob
A null Job B
B Job A Job C
C Job B null
My intention of these variables is that I can check with a soft constraint
rule, if the current chosen job and the job with which it gets compared are
consecutive jobs, and if so, how much time between these jobs is left.
In the soft constraint rule, I check if the “nextJob” Variable points to the
job, with which I’m currently comparing the job. If this is the case, then
there is no other job scheduled between those jobs and I can check how much
time between these jobs is left.
Every time drools planner reschedules a job, I have to check if nextJob and
prevJob of each job are still pointing to their right predecessor and
successor.
For example, if Job A gets moved to 8:00 the sequence could look like this:
Job Start date End date
A 8:00 am 9:00 am
B 7:30 am 8:00 am
C 12:00 am 1:00 pm
Therefore the variables preJob and nextJob have to be adjusted for each job:
Job prevJob nextJob
Job A Job B Job C
Job B null Job A
Job C Job A null
To achieve that, I use a list in which I save the current order of the
jobs.Furthermore I’ve written my own mover that, besides assigning the
current job to its new start date, updates the list and each job if a job
gets rescheduled.
You’ve probably got the punch line by now: It’s not working. And besides
from getting a scoreCurroption exception, I truly doubt that this is the
perfect solution for solving this planning problem.Have any of you an idea,
what a better way for solving this problem could be?
I’ve tried to find a similar problem in the examples, but none of them has
similar restrictions as mine. The curriculumcourse example has only fixed
time slots instead of a variable length and in the nurserostering, nurses
(jobs) get assigned to fixed shifts (time periods) and not the other way
around.
Thanks!
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13 years, 2 months
XML rule: Wrongly interpreted Numeric String to Number
by Christina Lau
Dear all,
System is generating XML rule file with literal-restriction like that:
...
<field-constraint field-name="myStringTypeField">
<literal-restriction evaluator="=="
value="0020" />
</field-constraint>
...
I am expecting the constraint is in form of
myStringTypeField == "0020"
However, the outcome is
myStringTypeField == 0020 (the double quote is missed)
causing my rule fails all the time.
Does anyone know if it it the problem of XML parsing? If yes, can I do
something to override the default parser behaviour?
Thank you very much.
Christina
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13 years, 2 months
passing empty string to a method with varargs failed on the second execution
by brachi
ContainsCODE.drl
<http://drools.46999.n3.nabble.com/file/n4021195/ContainsCODE.drl>
See attached DRL. input is: condContainsCODE=Lists.newArrayList("1", "2",
"4")
I Executed this DRL with the above input twice times. I got indexOutOfBound
Exception.
If I execute it *only one time* I didn't get this exception.
In addition, I found that if I change the rule to be *without the empty
string element*, then I didn't get this exception even if I run it twice
times.
This rule failed on the second time:
when condContainsCODE(Operators.contains(value,"1","2",*" "*))
this succeeded even in the second time:
when condContainsCODE(Operators.contains(value,"1","2"))
also this:
when condContainsCODE(*eval*(Operators.contains(value,"1","2",*" "*)))
That is the *Operators.contains* method:
public static boolean contains(Collection<?> c1, Object.. obj) {
return c1.containsAll(Lists.newArrayList(obj));
}
I read that are problems with varargs, but I don't understand why only
*space *causes problems, and why only in the *second time*?
looks like optimizer bug...
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13 years, 2 months
Is Drools suitable for preprocessing my Resource Allocation Problem
by Raphael Jolivet
Hello,
Here is a copy of a question I just sent on Stackoverflow :
http://stackoverflow.com/questions/13753983/is-drools-suitable-for-prepro...
I have a quite big resource allocation problem to compute.
I have just discovered Drools and I would like to know if it is a good
candidate to work as a preprocessor and generate a list of forbidden
allocations, based on some user rules.
The ProblemI have an optimisation engine that can allocate some activities
to some resources, while optimizing some KPIs (Key Performance Indicator).
The optimizer takes as input (among others) a list of forbiden allocations
that should be generated based on some user-provided rules.
Each forbid rule is an "AND" composition of two rules:
One for the activity
One for the resource
Each sub rule is itself a list of "AND" tests on some attributes.
Here is the structure of one rule, in Pseudo-Code
Rule1:
* ActivityRule
* activity.prop1 == "foo" AND
* activity.prop2 == "bar" AND
* ...
* ResourceRule
* resource.prop3 == "foobar" AND
* resource.prop4 == "NULL" AND
* ...
Rule2:
...
As soon as a pair of [Activity,Resource] matches one rule, it should be
sent as output, and not tested again against other rules.
Also, this is important to note that some rules will match very often,
while overs will match very rarely (very specific cases).
Performance constraints
Here are some rough hints about the volumetry of the problem :
* 1000 activities
* 200 resources
* 50 rules
I need the forbidden allocations to be generated in under a minute.
The challengeAs far, as I understand, Drools can surely generate those
forbidden allocations. the question is : "How smart is he" ?
If I had to write an engine myself for this particular problem, I would
make some improvements :
For example, I would not generate all possible allocations (200.000) and
then try to apply each rule on it (50 rules x 200.000).
Instead, I would try to match the resources and the activities separately
on each rule (each side of the rule), and then assemble the couples that
match at least one common rule.
Also, I would add some counter on each rule that would auto increment upon
each match, in order to apply first the rules that match often.
QuestionsIs the engine of Drools smart enought for that ? Or is he even
smarter ?
Do you have an example of Drools being used in a similar problem with
success ?
Do you have some hints on how to modelise this problem in Drools ?
Thanks in advance for your advice.
13 years, 2 months
