Re: [rules-users] Creating objects in WHEN clause

From: David Boaz <davidb(a)dbmotion.com&gt; Subject: Re: [rules-users] Creating objects in WHEN clause To: rules-users(a)lists.jboss.org Date: Sunday, March 1, 2009, 5:03 AM Thanks Greg, I tried to apply your solution proposed bellow, but had problem setting the initial "agenda-group". I'm using Drools 5.0.0.M4 version, and working with a StatelessSession API. Can you please give an example how to set the initial "agenda-group" from the StatelessSession API? BTW, regarding the discussion we had, whether to use FROM or WorkingMemory objects, is it applicable also when using a stateless session? Thanks, David Greg Barton wrote: > > I'd second this idea, and to get around the inconcenience of inserting the > Quantity objects from the calling application, use a rule that fires once > on initialization. > > rule > no-loop true > when > //No condition > then > insert(new Quantity("m", 2)); > end > > This rule should fire first. You could also put it in it's own > agenda-group (call it "initialization" or some such) and set focus to that > group when starting. > > rule > agenda-group "initialization" > no-loop true > when > //No condition > then > insert(new Quantity("m", 2)); > drools.setFocus("whatever_your_next_group_is"); > end > > --- On Wed, 2/25/09, Mauricio Salatino <salaboy(a)gmail.com&gt; wrote: > >> From: Mauricio Salatino <salaboy(a)gmail.com&gt; >> Subject: Re: [rules-users] Creating objects in WHEN clause >> To: "Rules Users List" <rules-users(a)lists.jboss.org&gt; >> Date: Wednesday, February 25, 2009, 11:40 AM >> How about : >> WHEN >> $quantity: Quantity(value == 2, unit == "m") >> $Person($height == $quantity:) >> then >> ... >> >> >> >> On Wed, Feb 25, 2009 at 2:27 PM, David Boaz >> <davidb(a)dbmotion.com&gt; wrote: >> > >> > In my application, we often compare the fact's >> field values against a known >> > object. For example: >> > WHEN person(height> new Quantity(2, "m")) >> // the height is greater than 2 >> > meters. >> > will DROOLS create a "singleton" Quantity >> object, or will it create one >> > object for each fact evaluation? >> > >> > We consider using anoter approach, using GLOBALS. >> Then, the Quantity object >> > will be created applicatively, and passed by the API >> to the engine. >> > something like: >> > GLOBAL Quantity 2meters >> > WHEN person(height > 2meters) >> > But this approach is combersom, because the rule >> author has to define part >> > of the information in the calling application, and >> part in the rule. >> > >> > Do you have a good practice how to handle these >> situations? >> > >> > Thanks, David >> > -- >> > View this message in context: >> http://www.nabble.com/Creating-objects-in-WHEN-clause-tp22207616p22207616... >> > Sent from the drools - user mailing list archive at >> Nabble.com. >> > >> > _______________________________________________ >> > rules-users mailing list >> > rules-users(a)lists.jboss.org >> > https://lists.jboss.org/mailman/listinfo/rules-users >> > >> >> >> >> -- >> - Salatino Mauricio - >> _______________________________________________ >> rules-users mailing list >> rules-users(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users > > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > -- View this message in context: http://www.nabble.com/Creating-objects-in-WHEN-clause-tp22207616p22271386... Sent from the drools - user mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users