How to suppress 'spurious' update events where the entry is identical

Question

We often have clusters with event listeners on reference data caches. These caches are refreshed by calling putAll() to update values efficiently. Although this is efficient, and keeps refresh code simple, many unwanted 'spurious' update events are generated. Spurious in the sense that in most of update events the old and new values are the same.
We considered using a MapTrigger to suppress these uninteresting update events. The problem is how to implement a 'veto' in the MapTrigger.process method. What we'd like to do from a trigger is:
if (old value == new value)
  ignore new entry
else
  process, enrich, or validate new entry as desired...
end ifWe'd like a clean way to signal from a MapTrigger that an entry should be ignored (rather than rejected). The Javadoc shows two possibilities:
*(1)* undo the pending change by resetting the entry value to the original value obtained from MapTrigger.Entry.getOriginalValue();
*(2)* reject the pending change by throwing a RuntimeException, which will prevent any changes from being committed, and will result in the exception being thrown from the operation that attempted to modify the map
Of these *(2)* Causes a put() failure in the client. That is appropriate for something like a validation failure, but not for simply ignoring an unwanted update. Option *(1)* unfortunately generates an update event!
Our current workaround is a MapEventTransformer to suppress the spurious updates:
public class UpdateSupressionTransformer implements MapEventTransformer {     
  /** Avoid sending an update event if the value is unchanged */
  public MapEvent transform(MapEvent e) {
    if (e.getId() == MapEvent.ENTRY_UPDATED) {
      if (e.getNewValue().equals(e.getOldValue())) {
        return null;
    return e;
}This works well but requires client code to register event listeners correctly. It also means that the unecessary change is still generated in the cache. For example a cache stores will be called needlessly.
Can a feature be considered to allow a clean way for identical updates to be ignored, or to not generate events?
Ideally this would be before the update is made - like a trigger. It seems a pity the MapTrigger design does not allow this.
Such a feature would allow simple cache refresh logic using putAll() - without having to check for deltas - avoiding large numbers of unwanted update events. We think this is likely to be a common requirement.
Cheers,
phil

Answer 1

Hi,
I dont think that this is the problem associated with portal.You are working on BI queries in portal but BI screen that you are working on is of SAP R/3 correct me is i am wrong??And the message you are getting is of R/3 screen,BI screens are shown in an iview and an iview cant show any message..
Regards,
Ameya