Triggering more then 1 rules in DROOLS DRL File - drools

Question

I have a drl file containing 10 rules. Each has a condition like -
Rule 1
when
field1 == "X"
then
status == "A"
Rule 2
when
field1 == "Y"
then
status == "A"
So as seen based on value of variable field1 rules are to be executed.
Now I have a object containing more then 1 value like List. So if the List contains both values X & Y, only Rule 1 is applied and then processing is stopped. Rule 2 is never triggered.
Is there any way I can ask DROOLS to continue applying Rules even if 1 rule is successful ?

Answer 1

The correct way of writing a rule that matches a String field (called field) in a class Type is
rule "match field"
when
Type( field == "X" )
then
//...
end
You can write another rule where you match against "Y", which is indicated if you need to do something else. If you want to do the same, you can write a slightly more complex test:
rule "match field"
when
Type( field == "X" || == "Y" )
then
//...
end
(Yes, this unusual syntax is permitted in Drools' DRL language.)
To test for a value contained in a List, you can write
rule "match list element"
when
List( this contains "X" )
then
//...
end
Again, you can write another rule where you test for contains "Y", and it will fire, too, as long as the List<String> contains "X" and "Y".
A bare List as a fact in Working Memory is usually not a good idea. But if a class member is a List, a similar form can be used:
rule "match value in list member"
when
Type( list contains "X" )
then
//...
end
There is no need for special precaution to be taken for more than one rule firing. The standard activation session.fireAllRules() fires until all activations have been processed.
Some rule attributes may have the effect of terminating the processing of activations prematurely - use them cautiously.

Answer 2

Try calling fireAllRules(); available in Drools session.
It provides you following variances:
fireAllRules();
fireAllRules(AgendaFilter agendaFilter)
fireAllRules(AgendaFilter agendaFilter, int max)
fireAllRules(int max)
In last two variances, max is the upper limit on the rules to be fired. In your example, if you use max as 10, it can fire all 10 rules provided they meet the criteria.
Please Note: The rules should be configured in such a way that they qualify for execution based on the updated state. Request you to review the criteria fragment (the when clause of the rules and ensure that they indeed result into positive evaluation during execution.
e.g. if rules are written like below:
Rule 1
when
field1 == "X"
then
status == "A"
Rule 2
when
field1 == "Y"
then
status == "A"
then either field1 == "X" is true or field1 == "Y" is true and thus will trigger one rule at MAX.
But if we write the rules like
Rule 1
when
field1 == "X" || field1 == "Y"
then
status == "A"
Rule 2
when
field1 == "X" || field1 == "Y"
then
status == "A"
then both the rules i.e. Rule 1 and Rule 2 will qualify if field1 is X or Y.
Hope this helps.

Answer 3

I'm going to give you a bit of a different answer because I don't know what drools is but I can tell you how we do this in other languages. Basically it requires a string builder concept and some logic touch point changes.
Set your string:
string yourLongerStatusStringSetter = '';
Work through your checking and append your string:
Rule 1 when field1 == "X" then yourLongerStatusStringSetter &= "Meets Status A criteria."
Rule 2 when field1 == "Y" then yourLongerStatusStringSetter &= " Meets Status B criteria."
Continue rules and checks and appending (provided criteria is met)
Output your 'statuses':
howeverYouWriteYourOutput( yourLongerStatusStringSetter )
Which will print to the screen:
Meets Status A criteria. Meets Status B criteria
Just food for thought on an alternate approach.