code: private boolean isCurrentStageCompleted() {
  
  		if (this.indexToCurrentExecutionStage >= this.stages.size()) {
  			return true;
  		}
  
  		final ExecutionGraphIterator it = new ExecutionGraphIterator(this, this.indexToCurrentExecutionStage, true,
  			true);
  		while (it.hasNext()) {
  			final ExecutionVertex vertex = it.next();
  			if (vertex.getExecutionState() != ExecutionState.FINISHED) {
  				return false;
  			}
  		}
  
  		return true;
  	}
docs: Checks if the current execution stage has been successfully completed, i.e.
  all vertices in this stage have successfully finished their execution.
  
  @return <code>true</code> if stage is completed, <code>false</code> otherwise