If the list inside Event has never being initialised it will throw a null point exception.. so you need to make sure that the list is initialised properly.
Regards On Mon, Mar 10, 2014 at 1:43 PM, Sandhya Sree <sandhyachinna...@gmail.com>wrote: > Exception in thread "pool-2-thread-1" Exception executing consequence for > rule "size" in com.net: java.lang.NullPointerException > at > org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39) > at > org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1297) > at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1221) > at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1456) > at > org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:710) > at > org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:674) > at > org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:230) > at com.net.RuleExecutor.execute(RuleExecutor.java:18) > at com.net.DirectoryMonitor.run(DirectoryMonitor.java:39) > at > java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) > at java.lang.Thread.run(Thread.java:744) > Caused by: java.lang.NullPointerException > at > com.net.Rule_size_dc2a47e2812648e69eb9581eda931496.defaultConsequence(Rule_size_dc2a47e2812648e69eb9581eda931496.java:9) > at > com.net.Rule_size_dc2a47e2812648e69eb9581eda931496DefaultConsequenceInvokerGenerated.evaluate(Unknown > Source) > at > com.net.Rule_size_dc2a47e2812648e69eb9581eda931496DefaultConsequenceInvoker.evaluate(Unknown > Source) > at > org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287) > > > On Mon, Mar 10, 2014 at 7:08 PM, Mauricio Salatino <sala...@gmail.com>wrote: > >> Please copy the entire stack trace.. what you have copied doesn't mean >> anything besides that there is something wrong. >> >> >> On Mon, Mar 10, 2014 at 1:29 PM, Sandhya Sree <sandhyachinna...@gmail.com >> > wrote: >> >>> im getting the following error on doing that >>> >>> Exception in thread "pool-2-thread-1" Exception executing consequence >>> for rule "size" in com.net: java.lang.NullPointerException >>> >>> what might be the problem? >>> >>> >>> >>> On Mon, Mar 10, 2014 at 4:16 PM, Wolfgang Laun >>> <wolfgang.l...@gmail.com>wrote: >>> >>>> Seeing that the list is static you can use the usual way for accessing >>>> a static class member: >>>> >>>> Event.listOfEvent.add( ... ); >>>> >>>> @Mauricio: It's not unusual to maintain a static collection (even >>>> though there may be better ways, esp. with Drools). >>>> >>>> >>>> >>>> On 10/03/2014, Mauricio Salatino <sala...@gmail.com> wrote: >>>> > Can you please elaborate about why do you want to do that? what's the >>>> point >>>> > of having a list inside of the Event class that will contain the same >>>> > event? >>>> > >>>> > The "Then" side of the rule is pure java.. so you just do >>>> > event.getEvents().add(event); >>>> > >>>> > but I don't see the point of doing that. >>>> > >>>> > Regards >>>> > >>>> > >>>> > On Mon, Mar 10, 2014 at 10:31 AM, Sandhya Sree >>>> > <sandhyachinna...@gmail.com>wrote: >>>> > >>>> >> hi , >>>> >> >>>> >> i have a class called Event which is as follows: >>>> >> >>>> >> public class Event { >>>> >> private String name; >>>> >> private File source; >>>> >> private Date timeStamp; >>>> >> public static List<Event> listOfEvents; >>>> >> >>>> >> public Event(String name, File source, Date timeStamp) { >>>> >> this.name = name; >>>> >> this.source = source; >>>> >> this.timeStamp = timeStamp; >>>> >> } >>>> >> public String getName() { >>>> >> return name; >>>> >> } >>>> >> public void setName(String name) { >>>> >> this.name = name; >>>> >> } >>>> >> public File getSource() { >>>> >> return source; >>>> >> } >>>> >> public void setSource(File source) { >>>> >> this.source = source; >>>> >> } >>>> >> public Date getTimeStamp() { >>>> >> return timeStamp; >>>> >> } >>>> >> public void setTimeStamp(Date timeStamp) { >>>> >> this.timeStamp = timeStamp; >>>> >> } >>>> >> >>>> >> >>>> >> public void display() >>>> >> { >>>> >> System.out.println(name +" " + "in folder: " + source + " on " + >>>> >> timeStamp ); >>>> >> } >>>> >> >>>> >> >>>> >> >>>> >> there are also some other classes associated with my project.. i >>>> have a >>>> >> rules file which computes the size of a folder and creates an object >>>> of >>>> >> Event class. every time this object of Event class is created i >>>> wwant to >>>> >> put it in a List<Event>.. how can i do this.. >>>> >> >>>> >> my rules is as follows: >>>> >> >>>> >> rule "size" >>>> >> when >>>> >> $p: RuleContext($size: >>>> getOldContext().getParent().getUsableSpace() > >>>> >> (30*1024*1024)) >>>> >> >>>> >> then >>>> >> Event event = new Event("folder almost full", >>>> >> $p.getOldContext().getParent(), new Date()); >>>> >> event.display(); >>>> >> ......here i want to put this event into the List<Event> declared >>>> in >>>> >> Event Class..... >>>> >> >>>> >> end >>>> >> >>>> >> >>>> >> >>>> >> thanks, >>>> >> Sandhya >>>> >> >>>> >> _______________________________________________ >>>> >> rules-users mailing list >>>> >> rules-users@lists.jboss.org >>>> >> https://lists.jboss.org/mailman/listinfo/rules-users >>>> >> >>>> > >>>> > >>>> > >>>> > -- >>>> > - MyJourney @ http://salaboy.com <http://salaboy.wordpress.com> >>>> > - Co-Founder @ http://www.jugargentina.org >>>> > - Co-Founder @ http://www.jbug.com.ar >>>> > >>>> > - Salatino "Salaboy" Mauricio - >>>> > >>>> _______________________________________________ >>>> rules-users mailing list >>>> rules-users@lists.jboss.org >>>> https://lists.jboss.org/mailman/listinfo/rules-users >>>> >>> >>> >>> _______________________________________________ >>> rules-users mailing list >>> rules-users@lists.jboss.org >>> https://lists.jboss.org/mailman/listinfo/rules-users >>> >> >> >> >> -- >> - MyJourney @ http://salaboy.com <http://salaboy.wordpress.com> >> - Co-Founder @ http://www.jugargentina.org >> - Co-Founder @ http://www.jbug.com.ar >> >> - Salatino "Salaboy" Mauricio - >> >> _______________________________________________ >> rules-users mailing list >> rules-users@lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users >> > > > _______________________________________________ > rules-users mailing list > rules-users@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > -- - MyJourney @ http://salaboy.com <http://salaboy.wordpress.com> - Co-Founder @ http://www.jugargentina.org - Co-Founder @ http://www.jbug.com.ar - Salatino "Salaboy" Mauricio -
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