Re: [rules-users] Need help in formulating rule (using list)

Hi Wolfgang, thanks for your reply. I did have the idea about having the concepts of first, last,predecessor, successor etc. in TimeEntry. Unfortunately, it really isn't possible because this class (i.e TimeEntry) is a main part of a huge application model, which has been existing since long, has many dependencies to other classes, and shouldn't be changed ("only" for fulfilling the requirement of rules-engine) . So unfortunately I can only use those which are available to me. That's why I was hoping if there's really pure rule-based solution to this. Regards ________________________________ From: Wolfgang Laun <wolfgang.laun(a)gmail.com&gt; To: Rules Users List <rules-users(a)lists.jboss.org&gt; Sent: Wed, November 11, 2009 11:29:29 AM Subject: Re: [rules-users] Need help in formulating rule (using list) Implied by the List representation are concepts such as "first", "last", "predecessor" and "successor". All of these may or may not be represented by the fields in TimeEntry. This would be so if it is *guaranteed* that one TimeEntry's start time is another one's end time; (and then you wouldn't even need them being sorted). Failing this, an explicit representation by adding an ordinal number or (as I prefer doing) a reference to the previous and next TimeEntry might be considered. But, either way, reasoning over pairs of TimeEntry objects (of one Schedule) requires that they are all (at least temporarily) present as facts in WM. Then, to be identified as TimeEntrys of a specific Schedule, they also could have a reference to that. It's a simple task to write a rule that fires for a new Schedule and creates the extended TimeEntryPlus facts from its List<TimeEntry>. To avoid NPEs, I'd add a dummy TimeEntryPlus object (type=="OFF") before and after. Then, you could write rules rule checkValidBreak1 when     $break : TimeEntryPlus( type == "BREAK" )     TimeEntryPlus( type == "WORK", succ == $break || pred == $break, length <= 10 ) then   System.out.println( "Short work b/a break " + ... $break ..., $break.getSchedule() ... ) end rule checkValidBreak2 when     $break : TimeEntryPlus( type == "BREAK" )     TimeEntryPlus( type == "WORK", succ == $break ) then   System.out.println( "Can't start with a break " + ... $break ..., $break.getSchedule() ... ) end -W On Wed, Nov 11, 2009 at 10:46 AM, psentosa <psentosa(a)yahoo.com&gt; wrote: _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users