Re: [rules-users] ClassCastException when comparing date type with literal

Thanks for your kindly reply. For the "mitigated restriction", do you mean I can use Order( eval( $msg.getDate().compareTo( new Date(...) ) ) ) # in 5.2.0 and 5.3.0? Can you give me any example or tell me any manual I can reference to? Thank you! On 31 March 2012 13:06, Wolfgang Laun <wolfgang.laun(a)gmail.com&gt; wrote: > On 31/03/2012, Zeke <xanadu860122(a)gmail.com&gt; wrote: > > It is just a test case used to bring up the issue. The real rule > condition > > in my business logic is more complex, like > > Order( id == '...', $msg.date > '...', num == $msg.num ). Of course I > > can > > change to use Message as Pattern to work aournd, but it is too tricky, > > right? And no matter the usage is weird or not, it is legal, right? > > > > I can't really say what was legal in 4.0.7, but > $msg: Message() > Order( $msg.date > '...' ) > was not legal in 5.1.1. For any constraint, the left hand side would have > to > be a reference to a field of the fact where it occurs. > Order(Id == '...') # is OK > You can refer to fields of another fact on the RHS: > Order(num == $msg.num ) # is OK > Any other expression would have to be written in clean Java (or MVEL) > but enclosed in eval() > Order( eval( $msg.getDate().compareTo( new Date(...) ) == 1 ) ) # or > similar ;-) > > Starting with 5.2.0, this restriction was mitigated and by 5.3.0 and > certainly in 5.4.0 a wide range of (boolean) expressions is > acceptable. > > However, I should emphasize that postponing the use of a constraint > into a later pattern is an antipattern for rule coding. Consider > $msg: Message() > This matches any fact of type Message, and the Engine must needs keep > track of this. Contrariwise, > $msg: Message( date > "...") > narrows this effort down. Putting a constraint where it belongs is not > a "workaround", it's best practice :) > > -W > > > > I am using Drools 4.0.7. If later release fixes this bug, I may try to > > upgrade. I don't want to change LHS. It will bring much effort in my > > project. > > > > > > On 30 March 2012 14:09, FrankVhh <frank.vanhoenshoven(a)agserv.eu&gt; wrote: > > > >> Let me rephrase my question: > >> > >> As date is an attribute of message, why don't you use: > >> > >> $msg : Message( date > "...") > >> > >> Constraining an attribute of Message in the Order pattern seems a weird > >> thing to do. > >> > >> > >> > >> Zeke-3 wrote > >> > > >> > It seems not work. > >> > When I try > >> > *$msg : Message($date : date) > >> > Order ( $date > "Mar-01-2012" )* > >> > I meet error "Unable to create Field Extractor for '$date' of > >> > '[ClassObjectType > >> > class=org.drools.examples.HelloWorldExample$Second]' > >> > in > >> > rule 'default' : [Rule name=default, agendaGroup=MAIN, salience=0, > >> > no-loop=false]" > >> > > >> > When I try > >> > *$msg : Message($date : date) > >> > eval ( $date > "Mar-01-2012" )* > >> > If the dialect is "java", I meet error "Rule Compilation error : > >> > [Rule > >> > name=default, agendaGroup=MAIN, salience=0, no-loop=false] > >> > org/drools/examples/test/Rule_default_0.java (8:354) : The > operator > >> > > > >> > is undefined for the argument type(s) Date, String" > >> > If the dialect is "mvel", I meet the same ClassCastException. > >> > > >> > On 29 March 2012 22:28, FrankVhh &lt;frank.vanhoenshoven@&gt; wrote: > >> > > >> >> This may sound a bit rude, but... why would you want to do such a > >> >> thing? > >> >> > >> >> If there is a constraint on the message, then why not put that > >> constraint > >> >> in > >> >> the message structure? > >> >> > >> >> Btw, I think it would work by using eval($date < "...") but see no > use > >> >> for > >> >> it either. > >> >> > >> >> > >> >> Joe Zendle wrote > >> >> > > >> >> > did you try: > >> >> > > >> >> > *$msg : Message($date : date) > >> >> > Order ( $date > "Mar-01-2012" )* > >> >> > > >> >> > > >> >> > > >> >> > 2012/3/29 Zeke &lt;xanadu860122@&gt; > >> >> > > >> >> >> Hi, guys: > >> >> >> I meet a strange issue and need your help again... I am using > >> Drools > >> >> >> 4.0.7. > >> >> >> When my rule condition is as *Message( date > "Mar-01-2012" )*, > >> >> >> everything is OK. But if I change it to be as below: > >> >> >> *$msg : Message() > >> >> >> Order ( $msg.date > "Mar-01-2012" )* > >> >> >> I will meet "java.lang.String cannot be cast to java.util.Date" > >> >> >> ClassCastException. "Order" is another fact. I attach the > exception > >> >> call > >> >> >> stack. Please check it. It looks like a bug to me. Do we fix it > >> >> >> in > >> >> later > >> >> >> release? If so, can you tell me which release contains the fix? > >> >> Thanks! > >> >> >> > >> >> >> _______________________________________________ > >> >> >> rules-users mailing list > >> >> >> rules-users@.jboss > >> >> >> https://lists.jboss.org/mailman/listinfo/rules-users > >> >> >> > >> >> >> > >> >> > > >> >> > _______________________________________________ > >> >> > rules-users mailing list > >> >> > rules-users@.jboss > >> >> > https://lists.jboss.org/mailman/listinfo/rules-users > >> >> > > >> >> > >> >> > >> >> -- > >> >> View this message in context: > >> >> > >> > http://drools.46999.n3.nabble.com/rules-users-ClassCastException-when-com... > >> >> Sent from the Drools: User forum mailing list archive at Nabble.com. > >> >> _______________________________________________ > >> >> rules-users mailing list > >> >> rules-users@.jboss > >> >> https://lists.jboss.org/mailman/listinfo/rules-users > >> >> > >> > > >> > _______________________________________________ > >> > rules-users mailing list > >> > rules-users@.jboss > >> > https://lists.jboss.org/mailman/listinfo/rules-users > >> > > >> > >> > >> -- > >> View this message in context: > >> > http://drools.46999.n3.nabble.com/rules-users-ClassCastException-when-com... > >> Sent from the Drools: User forum mailing list archive at Nabble.com. > >> _______________________________________________ > >> 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 >