If you can add the CatalogObject element data to working memory and if you can add a connective property ("parent" in the rule below) you can eliminate the use of "eval" (which does not allow the benefits of a RETE network to be fully realised) I think a rule like the below using 3.1-M1 would provide the same function as that shown by Michael Neale. Lots of assumptions but performance would be better. rule "UCCnet_DVE_Depth_All" when catalogObject : CatalogObject( ) elementValue( name = "depth", value == null | == "", parent == catalogObject ) then logWriter.logDebug( "Package Depth is Blank"); System.out.println( "Package Depth is Blank" ); end With kind regards, Mike ________________________________ From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Michael Neale Sent: 04 April 2007 05:18 To: Rules Users List Subject: Re: [rules-users] Need DRL authoring Help you are close ;) Yes, it is a challenge, thats what the examples are for etc. but try this (FYI I think you mean "or"): rule "UCCnet_DVE_Depth_All" when catalogObject : CatalogObject( ) eval( catalogObject.getElementValue( "depth") == null || catalogObject.getElementValue( "depth") == "" ) # String depth = CatalogObject.getElementValue("depth") # depth == null # depth == "" # catalogObject : CatalogObject( depth == null) # catalogObject : CatalogObject( depth == "") then # DON'T do this logWriter : LogWriter(); # BUT you can pass in a logWriter global variable logWriter.logDebug( "Package Depth is Blank"); System.out.println( "Package Depth is Blank" ); end Hope that helps. In the up coming BRMS, there will be a GUI which also has a secret purpose of "coaching" what DRL looks like, for those who need to know. On 4/4/07, John.Tal(a)gxs.com <John.Tal(a)gxs.com&gt; wrote: Writing DRL is not easy for people new to drools. Can someone please help me understand how to write this simple rule? You can see the approaches I have taken. In this case I do not have getters and setters for the attributes I am checking. I need to pass parameters to the object for it to get the data. I can't get any of the code in the when block to be syntax proper. Existing DRL doc is lacking in this area. Thanks John rule "UCCnet_DVE_Depth_All" when catalogObject : CatalogObject( getElementValue( "depth") == null, getElementValue( "depth") == "") # String depth = CatalogObject.getElementValue("depth") # depth == null # depth == "" # catalogObject : CatalogObject( depth == null) # catalogObject : CatalogObject( depth == "") then logWriter : LogWriter(); logWriter.logDebug( "Package Depth is Blank"); System.out.println( "Package Depth is Blank" ); end _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users