code: protected EntityKey getEntityKey(Tuple tuple, AssociatedEntityKeyMetadata associatedEntityKeyMetadata) {
  		Object[] columnValues = new Object[ associatedEntityKeyMetadata.getAssociationKeyColumns().length];
  		int i = 0;
  
  		for ( String associationKeyColumn : associatedEntityKeyMetadata.getAssociationKeyColumns() ) {
  			columnValues[i] = tuple.get( associationKeyColumn );
  			i++;
  		}
  
  		return new EntityKey( associatedEntityKeyMetadata.getEntityKeyMetadata(), columnValues );
  	}
docs: Returns the key of the entity targeted by the represented association, retrieved from the given tuple.
  
  @param tuple the tuple from which to retrieve the referenced entity key
  @return the key of the entity targeted by the represented association