Does anyone know a method to limit the number of results from a collect statement? I was just wondering how to do something like this: $myList : List() from collect( MyObject(myField == "something") ) limit 3 //it should put in $myList just the first 3 objects retrieved I'm quite sure there is nothing in Drools which can natively support something like that. So, how to do that, if needed? I tried this, but it seems not to be working (I can't understand why, though): $myList : List() from collect( MyObject(myField == "something") ) $myObject : MyObject() from $myList eval( $myList.indexOf($myObject) < 3 ) Indeed, it doesn't work because the link beetween $myList and $myObject seems to be released during any execution of the rule (In fact $myList.contains($myObject) returns false! Again, I can't understand why...) Any advice would be really appreciated! Regards, CG

Actually there is a $h in the code… sorry for the omission in the email. Just checked it again today – it gives me same result as yesterday : rule … when o : Date from accumulate ( Parent( $h : height ) , init(;), action(;), reverse(), result( $h ) ) then … end -Sergey ------------------------------ *From:* rules-users-bounces(a)lists.jboss.org [mailto: rules-users-bounces(a)lists.jboss.org] *On Behalf Of *Mark Proctor *Sent:* Wednesday, August 08, 2007 4:51 PM *To:* Rules Users List *Subject:* Re: [rules-users] bug in "accumulate" you didn't have a dollar on the field binding: Parent( h : height ) $ is optional, but you must use the same in all places. Mark Manukyan, Sergey wrote: Folks, Using 4.0. Think I found a bug in accumulate. The variables defined inside *<source pattern>* cannot be recognized inside of other parts of accumulate (action, result) f.e. rule … when o : Date from accumulate ( Parent( h : height ) , init(;), action(;), reverse(), result( $h ) ) then … end Produces : $h cannot be resolved Stack trace: at org.drools.rule.Package.checkValidity(*Package.java:408*) at org.drools.common.AbstractRuleBase.addPackage(* AbstractRuleBase.java:288*) at com.lear.rules.RuleBaseFacade.getRuleBase(*RuleBaseFacade.java:46 *) -Sergey ********************** ** LEGAL DISCLAIMER ** ********************** This E-mail message and any attachments may contain legally privileged, confidential or proprietary information. If you are not the intended recipient(s), or the employee or agent responsible for delivery of this message to the intended recipient(s), you are hereby notified that any dissemination, distribution or copying of this E-mail message is strictly prohibited. If you have received this message in error, please immediately notify the sender and delete this E-mail message from your computer. ------------------------------ _______________________________________________ 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

I found an interesting implementation to do that. If anyone is interested I could share my solution. Regards, CG Mark Proctor wrote: > > There is no supported way to do this. You could use an inline-eval > against a global, but that is very clunkey. However it does seem like a > good feature idea for a future release, open a jira and I'll look into > getting it included. > > Mark > pentarious wrote: >> Does anyone know a method to limit the number of results from a collect >> statement? I was just wondering how to do something like this: >> $myList : List() from collect( MyObject(myField == "something") ) limit 3 >> //it should put in $myList just the first 3 objects retrieved >> I'm quite sure there is nothing in Drools which can natively support >> something like that. So, how to do that, if needed? I tried this, but it >> seems not to be working (I can't understand why, though): >> $myList : List() from collect( MyObject(myField == "something") ) >> $myObject : MyObject() from $myList >> eval( $myList.indexOf($myObject) < 3 ) >> Indeed, it doesn't work because the link beetween $myList and $myObject >> seems to be released during any execution of the rule (In fact >> $myList.contains($myObject) returns false! Again, I can't understand >> why...) >> >> Any advice would be really appreciated! >> >> Regards, >> >> CG >> > > _______________________________________________ > 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/How-to-limit-results-from-a-collect-statement-tf423... 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

Ok, I'm still working on that, I'll publish my solution asap. In the meantime it turns out our requirements need something more than that. We have an ordered list of beans (items) and we have to be able to modify a specific subset of the list (adding a discount). Now I tried to solve this problem by working directly on the list of items. But I can't understand why this doesn't work: when $itemList : ArrayList() from collect( Item( category == "VIDEO" ) ) then ItemDiscount disc = new ItemDiscount(10); $myFirstItem = (Item)$itemList.get(0); $mySecondItem = (Item)$itemList.get(1); $myFirstItem.addDiscount(disc); $mySecondItem.addDiscount(disc); After executing this rule it's like nothing happened! I mean no discount has been added to the two items! The problem seems to be related to extracting items from the list. Apparently, every time we get an item from the list, it looses its link with the original item (I don't know if it's a copy of the original item or whatever), so that every update doesn't affect the original item any more. But of course that's what we're interested in! We want to modify original items in the rule session. Am I missing something? Or Is it a bug? Regards, CG Edson Tirelli-3 wrote: > > Please, share with us! Send to the list! > > Edson > > 2007/8/21, pentarious <cristiano.giuffrida(a)gmail.com&gt;: >> >> >> I found an interesting implementation to do that. If anyone is interested >> I >> could share my solution. >> >> Regards, >> >> CG >> >> >> Mark Proctor wrote: >> > >> > There is no supported way to do this. You could use an inline-eval >> > against a global, but that is very clunkey. However it does seem like a >> > good feature idea for a future release, open a jira and I'll look into >> > getting it included. >> > >> > Mark >> > pentarious wrote: >> >> Does anyone know a method to limit the number of results from a >> collect >> >> statement? I was just wondering how to do something like this: >> >> $myList : List() from collect( MyObject(myField == "something") ) >> limit >> 3 >> >> //it should put in $myList just the first 3 objects retrieved >> >> I'm quite sure there is nothing in Drools which can natively support >> >> something like that. So, how to do that, if needed? I tried this, but >> it >> >> seems not to be working (I can't understand why, though): >> >> $myList : List() from collect( MyObject(myField == "something") ) >> >> $myObject : MyObject() from $myList >> >> eval( $myList.indexOf($myObject) < 3 ) >> >> Indeed, it doesn't work because the link beetween $myList and >> $myObject >> >> seems to be released during any execution of the rule (In fact >> >> $myList.contains($myObject) returns false! Again, I can't understand >> >> why...) >> >> >> >> Any advice would be really appreciated! >> >> >> >> Regards, >> >> >> >> CG >> >> >> > >> > _______________________________________________ >> > 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/How-to-limit-results-from-a-collect-statement-tf423... >> 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 >> > > > > -- > Edson Tirelli > Software Engineer - JBoss Rules Core Developer > Office: +55 11 3529-6000 > Mobile: +55 11 9287-5646 > JBoss, a division of Red Hat @ www.jboss.com > > _______________________________________________ > 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/How-to-limit-results-from-a-collect-statement-tf423... 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

I know. Actually I didn't put any update or insert statement in the code just to make it simpler. The actual code looks like: when $itemList : ArrayList() from collect( Item( category == "VIDEO" ) ) then ItemDiscount disc = new ItemDiscount(10); insert(disc); $myFirstItem = (Item)$itemList.get(0); $mySecondItem = (Item)$itemList.get(1); $myFirstItem.addDiscount(disc); $mySecondItem.addDiscount(disc); update($myFirstItem); update($mySecondItem); Now, why this doesn't work at all? It does work if I write a rule for each item using in the when clause $item : Item from $itemList, but as I said I need to write a list-oriented rule. Regards, CG Edson Tirelli-3 wrote: > > If you want the "engine to see" your changes, in a way you affect other > rules, you must call update( object ) for the object you are changing. > Otherwise, the change will happen to the original object, but not to the > shadow proxy that the engine uses to ensure consistency. > > []s > Edson > > 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: >> >> >> Ok, I'm still working on that, I'll publish my solution asap. In the >> meantime >> it turns out our requirements need something more than that. We have an >> ordered list of beans (items) and we have to be able to modify a specific >> subset of the list (adding a discount). Now I tried to solve this problem >> by >> working directly on the list of items. But I can't understand why this >> doesn't work: >> when >> $itemList : ArrayList() from collect( Item( category == "VIDEO" ) ) >> then >> ItemDiscount disc = new ItemDiscount(10); >> $myFirstItem = (Item)$itemList.get(0); >> $mySecondItem = (Item)$itemList.get(1); >> $myFirstItem.addDiscount(disc); >> $mySecondItem.addDiscount(disc); >> >> After executing this rule it's like nothing happened! I mean no discount >> has >> been added to the two items! The problem seems to be related to >> extracting >> items from the list. Apparently, every time we get an item from the list, >> it >> looses its link with the original item (I don't know if it's a copy of >> the >> original item or whatever), so that every update doesn't affect the >> original >> item any more. But of course that's what we're interested in! We want to >> modify original items in the rule session. Am I missing something? Or Is >> it >> a bug? >> >> Regards, >> >> CG >> >> >> >> Edson Tirelli-3 wrote: >> > >> > Please, share with us! Send to the list! >> > >> > Edson >> > >> > 2007/8/21, pentarious <cristiano.giuffrida(a)gmail.com&gt;: >> >> >> >> >> >> I found an interesting implementation to do that. If anyone is >> interested >> >> I >> >> could share my solution. >> >> >> >> Regards, >> >> >> >> CG >> >> >> >> >> >> Mark Proctor wrote: >> >> > >> >> > There is no supported way to do this. You could use an inline-eval >> >> > against a global, but that is very clunkey. However it does seem >> like >> a >> >> > good feature idea for a future release, open a jira and I'll look >> into >> >> > getting it included. >> >> > >> >> > Mark >> >> > pentarious wrote: >> >> >> Does anyone know a method to limit the number of results from a >> >> collect >> >> >> statement? I was just wondering how to do something like this: >> >> >> $myList : List() from collect( MyObject(myField == "something") ) >> >> limit >> >> 3 >> >> >> //it should put in $myList just the first 3 objects retrieved >> >> >> I'm quite sure there is nothing in Drools which can natively >> support >> >> >> something like that. So, how to do that, if needed? I tried this, >> but >> >> it >> >> >> seems not to be working (I can't understand why, though): >> >> >> $myList : List() from collect( MyObject(myField == "something") ) >> >> >> $myObject : MyObject() from $myList >> >> >> eval( $myList.indexOf($myObject) < 3 ) >> >> >> Indeed, it doesn't work because the link beetween $myList and >> >> $myObject >> >> >> seems to be released during any execution of the rule (In fact >> >> >> $myList.contains($myObject) returns false! Again, I can't >> understand >> >> >> why...) >> >> >> >> >> >> Any advice would be really appreciated! >> >> >> >> >> >> Regards, >> >> >> >> >> >> CG >> >> >> >> >> > >> >> > _______________________________________________ >> >> > 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/How-to-limit-results-from-a-collect-statement-tf423... >> >> 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 >> >> >> > >> > >> > >> > -- >> > Edson Tirelli >> > Software Engineer - JBoss Rules Core Developer >> > Office: +55 11 3529-6000 >> > Mobile: +55 11 9287-5646 >> > JBoss, a division of Red Hat @ www.jboss.com >> > >> > _______________________________________________ >> > 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/How-to-limit-results-from-a-collect-statement-tf423... >> 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 >> > > > > -- > Edson Tirelli > Software Engineer - JBoss Rules Core Developer > Office: +55 11 3529-6000 > Mobile: +55 11 9287-5646 > JBoss, a division of Red Hat @ www.jboss.com > > _______________________________________________ > 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/How-to-limit-results-from-a-collect-statement-tf423... 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

I think I know what is happening. The getOptions() method is returning the shadowed options collections, i.e., when you are adding the option, you are adding to the shadow instead of the real object. Now, I'm not sure how we should handle such thing, since we do need to shadow the options collection. Mark, any idea? A workaround is: create an addOption() method to the Item class to add options, instead of doing getOptions().add(). This way the shadow proxy will delegate the call to your real class, instead of adding it to the shadow. []s Edson 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > > > Actually, before opening a JIRA I would like to show you my actual > code... > Here it is: > > rule "My Rule" > no-loop true > when > $list : ArrayList() from collect( Item( type == "MY TYPE" ) ) > then > Item item = (Item) $list.get(0); > ItemOption option = new ItemOption( item, "MY OPTION" ); > item.setType("MY NEW TYPE"); > item.getOptions().add( option ); > insert(option); > update(item); > end > > Basically we have some items (Item) and we need to take into > considerations > just items of type "MY TYPE", adding a new option "MY OPTION" to the list > of > the options of the first item in $list. Item is a bean with a field as > follows: > private Collection<ItemOption > options = new > ArrayList<ItemOption>(); > I thought it was worth writing again before opening a JIRA, as I've > looked > further into the problem and I found out another interesting thing. As > you > may have noticed I put two lines in my code: > item.setType("MY NEW TYPE"); > item.getOptions().add( option ); > It's interesting to notice that the first line works as expected (i.e. > after > executing the rule the item has a new type called "MY NEW TYPE"), while > the > second line doesn't (i.e. after executing the rule the item doesn't have > a > new option in its option list). So, do you think I should definitively > open > a JIRA (I've never opened one before, can you give a link just in case?) > or > I'm just missing something and there is a trivial solution to this issue? > > Regards, > > CG > > > Edson Tirelli-3 wrote: > > > > Well, it must work. Can you open a JIRA with a self contained test > > case > > please? I will investigate. > > > > []s > > Edson > > > > 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > >> > >> > >> I know. Actually I didn't put any update or insert statement in the > code > >> just > >> to make it simpler. The actual code looks like: > >> when > >> $itemList : ArrayList() from collect( Item( category == "VIDEO" > ) > ) > >> then > >> ItemDiscount disc = new ItemDiscount(10); > >> insert(disc); > >> $myFirstItem = (Item)$itemList.get(0); > >> $mySecondItem = (Item)$itemList.get(1); > >> $myFirstItem.addDiscount(disc); > >> $mySecondItem.addDiscount(disc); > >> update($myFirstItem); > >> update($mySecondItem); > >> Now, why this doesn't work at all? It does work if I write a rule for > >> each > >> item using in the when clause $item : Item from $itemList, but as I > said > >> I > >> need to write a list-oriented rule. > >> > >> Regards, > >> > >> CG > >> > >> > >> Edson Tirelli-3 wrote: > >> > > >> > If you want the "engine to see" your changes, in a way you affect > >> other > >> > rules, you must call update( object ) for the object you are > changing. > >> > Otherwise, the change will happen to the original object, but not to > >> the > >> > shadow proxy that the engine uses to ensure consistency. > >> > > >> > []s > >> > Edson > >> > > >> > 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > >> >> > >> >> > >> >> Ok, I'm still working on that, I'll publish my solution asap. In > the > >> >> meantime > >> >> it turns out our requirements need something more than that. We > have > >> an > >> >> ordered list of beans (items) and we have to be able to modify a > >> specific > >> >> subset of the list (adding a discount). Now I tried to solve this > >> problem > >> >> by > >> >> working directly on the list of items. But I can't understand why > this > >> >> doesn't work: > >> >> when > >> >> $itemList : ArrayList() from collect( Item( category == > "VIDEO" > ) > >> ) > >> >> then > >> >> ItemDiscount disc = new ItemDiscount(10); > >> >> $myFirstItem = (Item)$itemList.get(0); > >> >> $mySecondItem = (Item)$itemList.get(1); > >> >> $myFirstItem.addDiscount(disc); > >> >> $mySecondItem.addDiscount(disc); > >> >> > >> >> After executing this rule it's like nothing happened! I mean no > >> discount > >> >> has > >> >> been added to the two items! The problem seems to be related to > >> >> extracting > >> >> items from the list. Apparently, every time we get an item from the > >> list, > >> >> it > >> >> looses its link with the original item (I don't know if it's a copy > of > >> >> the > >> >> original item or whatever), so that every update doesn't affect the > >> >> original > >> >> item any more. But of course that's what we're interested in! We > want > >> to > >> >> modify original items in the rule session. Am I missing something? > Or > >> Is > >> >> it > >> >> a bug? > >> >> > >> >> Regards, > >> >> > >> >> CG > >> >> > >> >> > >> >> > >> >> Edson Tirelli-3 wrote: > >> >> > > >> >> > Please, share with us! Send to the list! > >> >> > > >> >> > Edson > >> >> > > >> >> > 2007/8/21, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > >> >> >> > >> >> >> > >> >> >> I found an interesting implementation to do that. If anyone is > >> >> interested > >> >> >> I > >> >> >> could share my solution. > >> >> >> > >> >> >> Regards, > >> >> >> > >> >> >> CG > >> >> >> > >> >> >> > >> >> >> Mark Proctor wrote: > >> >> >> > > >> >> >> > There is no supported way to do this. You could use an > >> inline-eval > >> >> >> > against a global, but that is very clunkey. However it does > seem > >> >> like > >> >> a > >> >> >> > good feature idea for a future release, open a jira and I'll > look > >> >> into > >> >> >> > getting it included. > >> >> >> > > >> >> >> > Mark > >> >> >> > pentarious wrote: > >> >> >> >> Does anyone know a method to limit the number of results from > a > >> >> >> collect > >> >> >> >> statement? I was just wondering how to do something like > this: > >> >> >> >> $myList : List() from collect( MyObject(myField == > "something") > >> ) > >> >> >> limit > >> >> >> 3 > >> >> >> >> //it should put in $myList just the first 3 objects retrieved > >> >> >> >> I'm quite sure there is nothing in Drools which can natively > >> >> support > >> >> >> >> something like that. So, how to do that, if needed? I tried > >> this, > >> >> but > >> >> >> it > >> >> >> >> seems not to be working (I can't understand why, though): > >> >> >> >> $myList : List() from collect( MyObject(myField == > "something") > >> ) > >> >> >> >> $myObject : MyObject() from $myList > >> >> >> >> eval( $myList.indexOf($myObject) < 3 ) > >> >> >> >> Indeed, it doesn't work because the link beetween $myList and > >> >> >> $myObject > >> >> >> >> seems to be released during any execution of the rule (In > fact > >> >> >> >> $myList.contains($myObject) returns false! Again, I can't > >> >> understand > >> >> >> >> why...) > >> >> >> >> > >> >> >> >> Any advice would be really appreciated! > >> >> >> >> > >> >> >> >> Regards, > >> >> >> >> > >> >> >> >> CG > >> >> >> >> > >> >> >> > > >> >> >> > _______________________________________________ > >> >> >> > 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/How-to-limit-results-from-a-collect-statement-tf423... > >> >> >> 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 > >> >> >> > >> >> > > >> >> > > >> >> > > >> >> > -- > >> >> > Edson Tirelli > >> >> > Software Engineer - JBoss Rules Core Developer > >> >> > Office: +55 11 3529-6000 > >> >> > Mobile: +55 11 9287-5646 > >> >> > JBoss, a division of Red Hat @ www.jboss.com > >> >> > > >> >> > _______________________________________________ > >> >> > 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/How-to-limit-results-from-a-collect-statement-tf423... > >> >> 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 > >> >> > >> > > >> > > >> > > >> > -- > >> > Edson Tirelli > >> > Software Engineer - JBoss Rules Core Developer > >> > Office: +55 11 3529-6000 > >> > Mobile: +55 11 9287-5646 > >> > JBoss, a division of Red Hat @ www.jboss.com > >> > > >> > _______________________________________________ > >> > 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/How-to-limit-results-from-a-collect-statement-tf423... > >> 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 > >> > > > > > > > > -- > > Edson Tirelli > > Software Engineer - JBoss Rules Core Developer > > Office: +55 11 3529-6000 > > Mobile: +55 11 9287-5646 > > JBoss, a division of Red Hat @ www.jboss.com > > > > _______________________________________________ > > 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/How-to-limit-results-from-a-collect-statement-tf423... > 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 > -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3529-6000 Mobile: +55 11 9287-5646 JBoss, a division of Red Hat @ www.jboss.com _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users

I do suggest you open a JIRA and attach your test case. I will need to do some debugging to understand what is happening. []s Edson 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > > I hope you can help me find a solution. In the meantime I've tried your > workaround, adding an addOption() method with no success. When I use that > method in the rule I get the following exception (and I can't understand > why): > java.lang.ClassNotFoundException: org.test.ItemShadowProxy > org.test.Item is the full qualified name of the bean Item. Any idea? > > Regards, > > CG > > > Edson Tirelli-3 wrote: > > > > I think I know what is happening. The getOptions() method is > returning > > the shadowed options collections, i.e., when you are adding the option, > > you > > are adding to the shadow instead of the real object. > > > > Now, I'm not sure how we should handle such thing, since we do need > to > > shadow the options collection. > > > > Mark, any idea? > > > > A workaround is: create an addOption() method to the Item class to > add > > options, instead of doing getOptions().add(). This way the shadow proxy > > will > > delegate the call to your real class, instead of adding it to the > shadow. > > > > []s > > Edson > > > > 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > >> > >> > >> Actually, before opening a JIRA I would like to show you my actual > >> code... > >> Here it is: > >> > >> rule "My Rule" > >> no-loop true > >> when > >> $list : ArrayList() from collect( Item( type == "MY TYPE" ) ) > >> then > >> Item item = (Item) $list.get(0); > >> ItemOption option = new ItemOption( item, "MY OPTION" ); > >> item.setType("MY NEW TYPE"); > >> item.getOptions().add( option ); > >> insert(option); > >> update(item); > >> end > >> > >> Basically we have some items (Item) and we need to take into > >> considerations > >> just items of type "MY TYPE", adding a new option "MY OPTION" to the > list > >> of > >> the options of the first item in $list. Item is a bean with a field as > >> follows: > >> private Collection<ItemOption > options = new > >> ArrayList<ItemOption>(); > >> I thought it was worth writing again before opening a JIRA, as I've > >> looked > >> further into the problem and I found out another interesting thing. As > >> you > >> may have noticed I put two lines in my code: > >> item.setType("MY NEW TYPE"); > >> item.getOptions().add( option ); > >> It's interesting to notice that the first line works as expected (i.e. > >> after > >> executing the rule the item has a new type called "MY NEW TYPE"), > while > >> the > >> second line doesn't (i.e. after executing the rule the item doesn't > have > >> a > >> new option in its option list). So, do you think I should definitively > >> open > >> a JIRA (I've never opened one before, can you give a link just in > case?) > >> or > >> I'm just missing something and there is a trivial solution to this > issue? > >> > >> Regards, > >> > >> CG > >> > >> > >> Edson Tirelli-3 wrote: > >> > > >> > Well, it must work. Can you open a JIRA with a self contained > test > >> > case > >> > please? I will investigate. > >> > > >> > []s > >> > Edson > >> > > >> > 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > >> >> > >> >> > >> >> I know. Actually I didn't put any update or insert statement in the > >> code > >> >> just > >> >> to make it simpler. The actual code looks like: > >> >> when > >> >> $itemList : ArrayList() from collect( Item( category == > "VIDEO" > >> ) > >> ) > >> >> then > >> >> ItemDiscount disc = new ItemDiscount(10); > >> >> insert(disc); > >> >> $myFirstItem = (Item)$itemList.get(0); > >> >> $mySecondItem = (Item)$itemList.get(1); > >> >> $myFirstItem.addDiscount(disc); > >> >> $mySecondItem.addDiscount(disc); > >> >> update($myFirstItem); > >> >> update($mySecondItem); > >> >> Now, why this doesn't work at all? It does work if I write a rule > for > >> >> each > >> >> item using in the when clause $item : Item from $itemList, but as > I > >> said > >> >> I > >> >> need to write a list-oriented rule. > >> >> > >> >> Regards, > >> >> > >> >> CG > >> >> > >> >> > >> >> Edson Tirelli-3 wrote: > >> >> > > >> >> > If you want the "engine to see" your changes, in a way you > affect > >> >> other > >> >> > rules, you must call update( object ) for the object you are > >> changing. > >> >> > Otherwise, the change will happen to the original object, but not > to > >> >> the > >> >> > shadow proxy that the engine uses to ensure consistency. > >> >> > > >> >> > []s > >> >> > Edson > >> >> > > >> >> > 2007/8/22, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > >> >> >> > >> >> >> > >> >> >> Ok, I'm still working on that, I'll publish my solution asap. In > >> the > >> >> >> meantime > >> >> >> it turns out our requirements need something more than that. We > >> have > >> >> an > >> >> >> ordered list of beans (items) and we have to be able to modify a > >> >> specific > >> >> >> subset of the list (adding a discount). Now I tried to solve > this > >> >> problem > >> >> >> by > >> >> >> working directly on the list of items. But I can't understand > why > >> this > >> >> >> doesn't work: > >> >> >> when > >> >> >> $itemList : ArrayList() from collect( Item( category == > >> "VIDEO" > >> ) > >> >> ) > >> >> >> then > >> >> >> ItemDiscount disc = new ItemDiscount(10); > >> >> >> $myFirstItem = (Item)$itemList.get(0); > >> >> >> $mySecondItem = (Item)$itemList.get(1); > >> >> >> $myFirstItem.addDiscount(disc); > >> >> >> $mySecondItem.addDiscount(disc); > >> >> >> > >> >> >> After executing this rule it's like nothing happened! I mean no > >> >> discount > >> >> >> has > >> >> >> been added to the two items! The problem seems to be related to > >> >> >> extracting > >> >> >> items from the list. Apparently, every time we get an item from > the > >> >> list, > >> >> >> it > >> >> >> looses its link with the original item (I don't know if it's a > copy > >> of > >> >> >> the > >> >> >> original item or whatever), so that every update doesn't affect > the > >> >> >> original > >> >> >> item any more. But of course that's what we're interested in! We > >> want > >> >> to > >> >> >> modify original items in the rule session. Am I missing > something? > >> Or > >> >> Is > >> >> >> it > >> >> >> a bug? > >> >> >> > >> >> >> Regards, > >> >> >> > >> >> >> CG > >> >> >> > >> >> >> > >> >> >> > >> >> >> Edson Tirelli-3 wrote: > >> >> >> > > >> >> >> > Please, share with us! Send to the list! > >> >> >> > > >> >> >> > Edson > >> >> >> > > >> >> >> > 2007/8/21, pentarious <cristiano.giuffrida(a)gmail.com&gt;: > >> >> >> >> > >> >> >> >> > >> >> >> >> I found an interesting implementation to do that. If anyone > is > >> >> >> interested > >> >> >> >> I > >> >> >> >> could share my solution. > >> >> >> >> > >> >> >> >> Regards, > >> >> >> >> > >> >> >> >> CG > >> >> >> >> > >> >> >> >> > >> >> >> >> Mark Proctor wrote: > >> >> >> >> > > >> >> >> >> > There is no supported way to do this. You could use an > >> >> inline-eval > >> >> >> >> > against a global, but that is very clunkey. However it does > >> seem > >> >> >> like > >> >> >> a > >> >> >> >> > good feature idea for a future release, open a jira and > I'll > >> look > >> >> >> into > >> >> >> >> > getting it included. > >> >> >> >> > > >> >> >> >> > Mark > >> >> >> >> > pentarious wrote: > >> >> >> >> >> Does anyone know a method to limit the number of results > from > >> a > >> >> >> >> collect > >> >> >> >> >> statement? I was just wondering how to do something like > >> this: > >> >> >> >> >> $myList : List() from collect( MyObject(myField == > >> "something") > >> >> ) > >> >> >> >> limit > >> >> >> >> 3 > >> >> >> >> >> //it should put in $myList just the first 3 objects > retrieved > >> >> >> >> >> I'm quite sure there is nothing in Drools which can > natively > >> >> >> support > >> >> >> >> >> something like that. So, how to do that, if needed? I > tried > >> >> this, > >> >> >> but > >> >> >> >> it > >> >> >> >> >> seems not to be working (I can't understand why, though): > >> >> >> >> >> $myList : List() from collect( MyObject(myField == > >> "something") > >> >> ) > >> >> >> >> >> $myObject : MyObject() from $myList > >> >> >> >> >> eval( $myList.indexOf($myObject) < 3 ) > >> >> >> >> >> Indeed, it doesn't work because the link beetween $myList > and > >> >> >> >> $myObject > >> >> >> >> >> seems to be released during any execution of the rule (In > >> fact > >> >> >> >> >> $myList.contains($myObject) returns false! Again, I can't > >> >> >> understand > >> >> >> >> >> why...) > >> >> >> >> >> > >> >> >> >> >> Any advice would be really appreciated! > >> >> >> >> >> > >> >> >> >> >> Regards, > >> >> >> >> >> > >> >> >> >> >> CG > >> >> >> >> >> > >> >> >> >> > > >> >> >> >> > _______________________________________________ > >> >> >> >> > 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/How-to-limit-results-from-a-collect-statement-tf423... > >> >> >> >> 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 > >> >> >> >> > >> >> >> > > >> >> >> > > >> >> >> > > >> >> >> > -- > >> >> >> > Edson Tirelli > >> >> >> > Software Engineer - JBoss Rules Core Developer > >> >> >> > Office: +55 11 3529-6000 > >> >> >> > Mobile: +55 11 9287-5646 > >> >> >> > JBoss, a division of Red Hat @ www.jboss.com > >> >> >> > > >> >> >> > _______________________________________________ > >> >> >> > 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/How-to-limit-results-from-a-collect-statement-tf423... > >> >> >> 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 > >> >> >> > >> >> > > >> >> > > >> >> > > >> >> > -- > >> >> > Edson Tirelli > >> >> > Software Engineer - JBoss Rules Core Developer > >> >> > Office: +55 11 3529-6000 > >> >> > Mobile: +55 11 9287-5646 > >> >> > JBoss, a division of Red Hat @ www.jboss.com > >> >> > > >> >> > _______________________________________________ > >> >> > 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/How-to-limit-results-from-a-collect-statement-tf423... > >> >> 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 > >> >> > >> > > >> > > >> > > >> > -- > >> > Edson Tirelli > >> > Software Engineer - JBoss Rules Core Developer > >> > Office: +55 11 3529-6000 > >> > Mobile: +55 11 9287-5646 > >> > JBoss, a division of Red Hat @ www.jboss.com > >> > > >> > _______________________________________________ > >> > 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/How-to-limit-results-from-a-collect-statement-tf423... > >> 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 > >> > > > > > > > > -- > > Edson Tirelli > > Software Engineer - JBoss Rules Core Developer > > Office: +55 11 3529-6000 > > Mobile: +55 11 9287-5646 > > JBoss, a division of Red Hat @ www.jboss.com > > > > _______________________________________________ > > 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/How-to-limit-results-from-a-collect-statement-tf423... > 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 > -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3529-6000 Mobile: +55 11 9287-5646 JBoss, a division of Red Hat @ www.jboss.com _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users