[rules-users] Memory leak in 5.2/5.3

[Mark Proctor]

On 04/10/2011 22:51, alopez wrote:
> Good news, I followed your advice and patched drools-core to prevent this,
> focusing on removing all listeners:
>
> AbstractWorkingMemory.java, line 1246:
>
> for ( Iterator it = this.__ruleBaseEventListeners.iterator(); it.hasNext();
> ) {
>         this.ruleBase.removeEventListener( (RuleBaseEventListener) it.next()
> );
> }
>
> I changed that to:
>
> for ( Iterator it = this.ruleBase.getRuleBaseEventListeners().iterator();
> it.hasNext(); ) {
>         this.ruleBase.removeEventListener( (RuleBaseEventListener) it.next()
> );
> }
>
> And now works OK, no memory leak.
That is not safe, and incorrect. __ruleBaseEventListener is the list of 
rulebase listeners that the current WM adds ot the rulebase.
     public void addEventListener(RuleBaseEventListener listener) {
         this.ruleBase.addEventListener( listener );
         this.__ruleBaseEventListeners.add( listener );
     }
  When the WM is disposed it should remove it's listeners only. so it 
iterates __ruleBaseEventListener to find those, and remove them from the 
rulebase .

What you are doing is iterating the rulebase and removing ALL it's  
listeners, which means it'll remove listeners that belong to other wms.

If you are getting a leak like this, it means some how the wm is adding  
listener, that is not removed - i.e. a listener is not added to 
__ruleBaseEventListener but is still added to rulebase.

If you want this fixed for 5.3,  we need a test producing the issue by 
today.

Mark
>
> Thanks
>
>
>
> --
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