drools | rules engine - Examples about drools7 | Rule Engine library

You asked

Is it possible to tell it which order to run the rules files in, or which files to skip for each use case?

The answer is yes. The method to do this is called salience. The linked article is a good source to learn about this. This is important because salience can make it possible to change the order of execution of rules.

Hypothetically, let say that you have a program that process transactions based on categories. So, if category == deposit, you want to add to current balance. You have another rule that if category == withdrawal you want to subtract from current balance. BUT, you want to process deposits over withdrawals. Using salience you can guarantee that the deposits rule will fire before the withdrawal rule regardless of order of transaction.

Dependency is kind of related, but not the same. In drools, this is know as Forward or Backward Chaining depending on the order. This is all composed based on a series of facts. For example, if I was to ask a system "is my house on planet Earth?" the conclusion is reached if the following facts exist:

1. My house is in Fort Worth
2. Fort Worth is a city in Texas
3. Texas is a state in the United States
4. United States is a country on Earth

A direct fact linking the house location to this planet is asserted based on the rules that verify the enumerated facts above. This is done using chaining. Forward or backwards is just how these are processed (top-down or bottom-up). This is in a nutshell to the best of my recollection.

Your rule will hit for each item in working memory that matches.

Simplifying things, let's say that your model looks like this:

You use ruleflow-group 'default', thus you must set focus to agenda group to get rule executed, like getSession().getAgenda().getAgendaGroup("default").setFocus();

Most likely you set focus before or after event insertion. After inserting first message you set focus but no rule was added to the agenda (rule is not yet eligible for execution) at that time, and focus get reset to main agenda group. After 10 seconds you state that no rule was triggered despite that rule was added to 'default' agenda (because main group has focus). You insert second message and set focus to 'default' agenda which executes the rule from the agenda being triggered by the first message.

Rule is getting executed if you

1. remove ruleflow-group (latest documentation promote agenda-group)
2. add auto-focus true to the rule
3. set agenda group focus after 10 seconds

See how agenda group works

Increase memory, for example with VM option -Xmx4g

Also note that parallelBenchmarkCount AUTO currently doesn't take into account that moveThreadCount is not NONE. So your benchmarks will not be accurate, because if you have 16 cores, parallelBenchmarkCount AUTO will resolve to 8. With moveThreadCount 4 (+ 1 solver thread), you'll be using 32+ cores but only have 16 cores. This probably should be reported as an issue in optaplanner's jira for parallelBenchmarkCount AUTO.

I was able to reproduce NullPointerException for the first example only when I inserted objects without proper initialization. For the second case, indeed, this["DyrAlder"] < $param doesn't work, but this.get("DyrAlder") < $param, this.DyrAlder < $param and even DyrAlder < $param works for me.

According to your description I complicated your rules with desired ruleSet parameter to get working POC for your requirements. Out of 10 objects being inserted, only 5 fit condition DyrAlder < 5 and only 1 fits ruseSet == "set3", thus you have the rule triggered only once.

Test 1 (InputObject)

Looks like its not the case. In this thread you can find all apps impacted : https://gist.github.com/SwitHak/b66db3a06c2955a9cb71a8718970c592

InsuranceType is not in working memory -- Premium is. So you need to modify Premium, not insurance type.

There's really not a good way to do this. You could call update, but this will refire all rules (it's the equivalent of starting over with new data in working memory.)

I'm going to assume there's a public getName method on the InsuranceType class, and a public getInsuranceTypes method on the Premium class. If either of those isn't true, you need to add either getters or make those properties public.

Your rule was pretty close. However the problem you have is that insuranceTypes is a list but you were treating it as an object.

You have several options here, depending on your needs. However I'd go with the simplest, which is this:

I was able to solve it using the 'from' keyword