2011/3/25 Swindells, Thomas <TSwindells@nds.com>

I thought from was effectively typeless (as it’s operating against a List it can’t always know the type of the members anyway) and so it allows any type on teh left – giving a runtime class cast exception if it can’t do the conversion. Therefore if you know they type you are expecting you can still use it on the LHS with whatever constraints you want?


Sure, "from" doesn't care what it produces, but accumulate functions have to return an object of some type. Currently. min and max return java.lang.Double; therefore you can use java.lang.Number as a portmanteau type. If min and max should include Data (and all other Comparable's), the actual result type will have to be Comparable (or Object).

-W
 

 

Thomas

 

From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Wolfgang Laun
Sent: 25 March 2011 09:23
To: Rules Users List
Subject: Re: [rules-users] accumulate min over java.util.Date

 

Now don't be hasty with a JIRA. Using Comparable for the arguments of the min and max accumulate functions will give you a result that is -- Comparable. So:

  $min: Comparable() from accumulate( Schedule( $d: date ), min( $d ) )

OK, this will give you the minimum data, bound to $min, although it won't let you write any constraint for the "Comparable" result fact. But, what's worse, it will not let you write

  $min: Number( intValue > 100 ) from accumulate( X( $y: y ), min( $y ) )

any more (unless I'm very much mistaken).

-W


On 25 March 2011 03:56, Greg Barton <greg_barton@yahoo.com> wrote:

Well, if it can work that way it should.  I'd say open a JIRA and request that feature.  It works with the "principle of least confusion." :)


--- On Thu, 3/24/11, jkrupka <jkrupka@gmail.com> wrote:

> From: jkrupka <jkrupka@gmail.com>

> Subject: Re: [rules-users] accumulate min over java.util.Date

> Date: Thursday, March 24, 2011, 8:26 PM

> Yea the docs weren't really clear
> about it, so I just thought it would work
> for anything that implemented Comparable =)
>
> Yep, used the long from getTime() - not the prettiest way
> of doing it, but
> it works great.
>
> Thanks!
>
> --
> View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/accumulate-min-over-java-util-Date-tp2726081p2728477.html
> Sent from the Drools - User mailing list archive at
> Nabble.com.
> _______________________________________________
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> rules-users@lists.jboss.org
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>



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