Calling a custom function in drools lhs

Question

I need to write a custom function that does some checks on the facts in drools working memory and returns a number.

As far as I've figured out - I need to import the helper class which has the custom function.

Now how to access the working memory from the function? And how would I call that function in the LHS?

Answer 1

Functions can't actually access the working memory. You could bind the required facts in your rule and then send them as parameters to your function.

A better approach would be to use a Query instead of a function. You can read more about queries in Drools' documentation: http://docs.jboss.org/drools/release/6.3.0.Beta1/drools-docs/html_single/index.html#QuerySection