drools: how to assign to local variable

Question

I'm stuck with Drools 5 and need a little help. What I'd like to do is use a passed in DAO and assign a value from that to a local variable, like this...

rule "test rule 1"
when
    $carDao : ICarDAO( )
    $x : $carDao.getMap()
    eval (
       $x.contains("a") && $x.contains("b")
    )
then
// do stuff
end

Drools 5 doesn't allow assignment of local variables though. I'd like to assign to a local variable so that I don't have to make the same call twice to the DAO.

So could someone point me in the correct direction please?

Thanks! Jeff Porter

Solution 1

rule "test rule 1"
when
    $carDao : ICarDAO( $x : map )
    eval (
       $x.contains("a") && $x.contains("b")
    )
then
    // do stuff
end

or since 5.2:

rule "test rule 1"
when
    $carDao : ICarDAO( $x : map, map.contains("a"), map.contains("b") )
then
    // do stuff
end

Solution 2

rule "test rule 1"
when
    $carDao : ICarDAO( )
    $x: java.util.Map( ) from  $carDao.getMap()
    eval (
       $x.contains("a") && $x.contains("b")
    )
then
// do stuff
end

ta..dar!