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adding a event listener only once

I am adding a event listener to the singlteton class. But I am only wanting to add the listener one time. Right now I have it in a add method.

 public void add(TCComponentItemRevision tcRevision, TCComponentDataset selectedDataset) {
      String revMasterForm;
    ***  tcRevision.getSession().addAIFComponentEventListener(this); ***
      
      try {
         revMasterForm = tcRevision.getRelatedComponent("IMAN_master_form_rev").getUid();
         RevDataset pp = new RevDataset(tcRevision, selectedDataset, revMasterForm);
         if (!rds.contains(pp)) {
            rds.add(pp);
         }     
      }
      catch (TCException e) {
        
         e.printStackTrace();
      }
     
      fireTableDataChanged();
   }// end add()

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I don't want to add the listener everything a object is added to the array. How would I only add the listener once?

jkteater

ASKER

Maybe the question should be how to do check and see if the listener is already running.

Something like

If (Listener value == nul ) {
tcRevision.getSession().addAIFComponentEventListener(this);
}

not sure how to get the listener value

ASKER CERTIFIED SOLUTION

CEHJ

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jkteater

ASKER

where would you add the listener?

CEHJ

Ah well, that's just a guess based on instinct ;) Not knowing your setup, i couldn't begin to say. You should probably ignore that comment of mine ;)

jkteater

ASKER

I basically just created a boolean to check

if(!addedListener){
         tcRevision.getSession().addAIFComponentEventListener(this);
         addedListener = true;
      }

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Seems to work

CEHJ

So only one listener is possible?

jkteater

ASKER

Yes

CEHJ

Well if it can contain only one listener, then a boolean will suffice. However, that listener should be accessible to clients via a standard accessor method along the lines of getListener(). For that reason, no extra flag is necessary. In fact, an extra flag is error-prone as well as redundant. All you need is something like i posted in my last code illustration

CEHJ