[rules-users] Benefits of pluggable operators
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 operatorshttp://blog.athico.com/2010/06/creating-pluggable-oprators.html 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 ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Benefits of pluggable operators
Thomas, Pluggable operators were developed much before we supported free form expressions, but nowadays they can be used for the same purpose. It is then a matter of preference basically. You can still develop and use pluggable operators if that makes your rule more readable by hiding complexity related to parameter passing or something that would be required in a method call, but I can't think of any advantage or disadvantage in either approach in terms of performance or cost. If I remember correctly, pluggable operators were developed for Drools 4.0, while free form expressions were only fully functional in 5.3+ (limited functionality in 5.2). Edson On Fri, May 24, 2013 at 10:54 AM, Thomas Grayson tgray...@bluemetal.comwrote: 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 operatorshttp://blog.athico.com/2010/06/creating-pluggable-oprators.htmlblog 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 ** ** ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- Edson Tirelli JBoss Drools Core Development JBoss by Red Hat @ www.jboss.com ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Benefits of pluggable operators
I'm inclined to think that a well-implemented operator can provide a little bit more cushioning for the rule author. In the given example, key.startsWith(abc) would throw an NPE if key is null. The operator silently handle this case and simply return false. Another thing is that operators can be used with the single left hand side expression pattern, i.e., field opa x || opb y || opc y Syntactic sugar, certainly, but occasionally quite convenient. -W On 24/05/2013, Edson Tirelli ed.tire...@gmail.com wrote: Thomas, Pluggable operators were developed much before we supported free form expressions, but nowadays they can be used for the same purpose. It is then a matter of preference basically. You can still develop and use pluggable operators if that makes your rule more readable by hiding complexity related to parameter passing or something that would be required in a method call, but I can't think of any advantage or disadvantage in either approach in terms of performance or cost. If I remember correctly, pluggable operators were developed for Drools 4.0, while free form expressions were only fully functional in 5.3+ (limited functionality in 5.2). Edson On Fri, May 24, 2013 at 10:54 AM, Thomas Grayson tgray...@bluemetal.comwrote: 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 operatorshttp://blog.athico.com/2010/06/creating-pluggable-oprators.htmlblog 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 ** ** ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- Edson Tirelli JBoss Drools Core Development JBoss by Red Hat @ www.jboss.com ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
