[rules-users] looping in drools

[Davide Sottara]

"from" will iterate for you, exactly like "accumulate" counted the events.
If you need more details, please consult the documentation


On 03/10/2014 07:29 PM, Sandhya Sree wrote:
> The problem here is even if multiple files are added, there is only
> one event object created. i want to have like say if 3 new files are
> added, 3 event objects must be created, and all three event objects
> must be added to List<Event> listOfEvents. 
>
>
> Thanks.
>
>
> On Mon, Mar 10, 2014 at 11:48 PM, Davide Sottara <dsotty at gmail.com
> <mailto:dsotty at gmail.com>> wrote:
>
>     The "accumulates" should not be in the "then" part of a rule (see
>     my previous email).
>     That rule gave you two lists, in the variables $plus and $mins,
>     that you can use in the consequence.
>
>     If you need to process each file separately, you may want to do
>     something like this:
>
>     rule "new file"
>     when
>         FileData($old : fileOld, $new : fileNew, fileOld != fileNew)
>        $newFile : String( this not memberOf $old ) from $new
>     then  
>        // create new event for a new file : new Event(...)
>        // add to list : Event.listOfEvents.add(...)
>     end
>
>     You'll need another rule for the files that have been removed.
>
>     Notice that your Event class has no way to distinguish "added"
>     from "removed" files, you may want to
>     add a boolean or something there.
>     Best
>     Davide
>
>
>     On 03/10/2014 07:04 PM, Sandhya Sree wrote:
>>     hi,
>>     im new to drools..im trying to create a project as follows. i
>>     have a class called Monitor  which monitors a folder and creates
>>     two lists called fileOld( which is the list of filenames in that
>>     folder at time t1)  and fileNew(which is the list of filenames in
>>     that folder at time t2). i have another class called FileData
>>     which contains two members fileOld and fileNew (list of strings)
>>     with getters,setters and constructor. fileOld and fileNew from
>>     Monitor Class are passed to FileData class.
>>
>>     i also have another class called Event which is as follows:
>>     public class Event {
>>     public static String name;
>>     private  File source;
>>     private  Date timeStamp;
>>             public  static  List<Event> listOfEvents = new
>>     ArrayList<Event>();
>>      
>>     public Event(String name, File source, Date timeStamp) {
>>     this.name <http://this.name> = name;
>>     this.source = source;
>>     this.timeStamp = timeStamp;
>>     }
>>     public String getName() {
>>     return name;
>>     }
>>     public void setName(String name) {
>>     this.name <http://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;
>>     }
>>
>>     now i have to compare these two lists(fileOld and fileNew) in a
>>     rule file and if they are not equal i have to create an event
>>     object for every file added and deleted and put it in the
>>     List<Event> listOfEvents.
>>
>>     here is my rule file:
>>
>>     rrule "files are equal"
>>         when 
>>              FileData( fileOld == fileNew)
>>         then
>>            System.out.println("files are equal");
>>         end
>>
>>
>>     rule "files not equal"
>>     when
>>         FileData($old : fileOld, $new : fileNew, fileOld != fileNew)
>>         
>>     then
>>        accumulate( $s : String( this not memberOf $old ) from $new,
>>     $plus : collectList( $s ) ) 
>>        accumulate( $t : String( this not memberOf $new ) from $old,
>>     $mins : collectList( $t ) ) 
>>        System.out.println("files added:" + $plus ); 
>>        System.out.println( "files deleted:" + $mins );
>>     end
>>
>>
>>
>>     how can i loop through each of the file added or deleted and
>>     create an Event Class object for every file added and deleted
>>      and finally add all the created objects to List<Event>
>>     listOfEvents..
>>
>>
>>     Thanks.
>>
>>
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>>     https://lists.jboss.org/mailman/listinfo/rules-users
>
>
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