destinationIdentifier = ParameterExpander.expandExpression( aValueMap, destinationExpression );
generatorIdentifier = ParameterExpander.expandExpression( aValueMap, generatorExpression );
destinationIdentifier = ParameterExpander.expandExpression( aValueMap, destinationExpression );
generatorIdentifier = ParameterExpander.expandExpression( aValueMap, generatorExpression );