What are the benefits of using pluggable operators (implementations of org.drools.base.evaluators.EvaluatorDefinition such str, matches, or before) versus simply making an equivalent function call?  I’ve read the Creating pluggable operators blog post.  Apart from saying that the Eclipse plugin can recognize these operators, it doesn’t really make a case for why I’d want to create my own implementation.  One might argue that operators enhance reusability, but a static method offers much the same benefit.  Does a pluggable operator have any optimization, caching, or other advantage?

For example, here are two ways to match the start of a string in a property of a fact, one using  the “str[startsWith]” operator and another with Java’s String.startsWith method:

declare Fact

    key : String @key

end

rule "Use operator"

when

        Fact(key str[startsWith] "abc")

then

// do something

end

rule "Use method"

when

        Fact(key.startsWith("abc"))

then

// do something

end

Does one of these perform better than the other?

Best wishes,

Tom