Business Rules and Dates

Question

I have many Java POJOs imported as facts. In each of these POJOs there is at least 1 date property.
How am I to use these dates in my rules. for example:
pojo.date > '08/22/06'
pojo.date < today
println(pojo.date)
Although I have imported the java date class and have been over the docs many times, I cannot seem to figure out how to use the dates properly.
I'm also having a similar problem where I have large numbers stored as doubles. When I make a rule like: pojo.largenumber > 3000 I get the error :
Cannot perform operation. 'RUL-01726: Data type operator for >, at position 0: java.lang.Long > int '
Thanks for the help,

Answer 1

smartel2 wrote:
I understand we need to compare like values, just as we would in java and other
languages. however, I am trying to use the Rule Author to enter my rules, as my end
user / business analysts would. When I use the rule author I can't seem to use any of
the Date methods for example using the expert mode in the Rule Author
pojo1.getStarttime ().compareTo(pojo2.starttime)
gives: "Cannot perform operation. 'RUL-01717: "compareTo" is not a valid identifier
name. '" when I apply it.Ah, I see. You are doing this correctly. You need to import the Date class into the datamodel and then check the "expand" option for the getStarttime() method of the fact type of pojo1 (or, the expand option if there is a starttime bean property). It should show up then.
I also don't understand why my previous example "pojo.largenumber > 3000" would
need a conversion. Shouldn't the interpreter be smart enough to know that the left
side of the expression is a double and auto cast the right side constant '3000' as a
double to satisfy the condition?The error indicated that "largenumber" was a Long object, not a primitive double. If largenumber was a double, the cast should be done correctly. If it's not, it may be a bug. Post the code for the pojo class if you think otherwise.
How do I use the Rule Author to create these kinds of rules?I think the above mostly covers this one.
How would I use the Rule Author to create a rule for "pojo.startdate is after Sept 1, 2005"One suggestion I have is that you use the Calendar class instead of Date for doing date manipulation. Date is mostly deprecated, and basically only servers as a wrapper for a long number (seconds since the epoch). Most importantly, Date is not internationalizable.
Calendar has full support for locales, timezones, and all of the other necessary stuff for appropriately handling dates. A simple example of the reason for this class is that date formats differ significantly, for instance, "01/07/89" is January 7th, 1989 to an American, but is July 1st, 1989 to a European. Depending on the format, it could be July 1st, 0089 to a computer.
So, the answer to you question is to create a final variable that represents the date (either a Calendar or Date) and then use that. With Calendar, you have to also use the SimpleDateFormat object to initialize it. I would probably write a function to initialize all of the global final date objects.
How do I use standard java objects and there methods in the Rule Author, like Date.Answered above I think, but the short is to import them into the DataModel and then check the "expand" option for the property or method of that type that you want to access its properties and methods.
Do I have to create all my rules in pure RL language (full script) ?Could you clarify this question?
And finally, fully integrated date support is one of the things that's being worked on for the 11g release, so this should be much easier to handle in the future.