code: private void initialize(final SecurityContext securityContext,  Document document) throws FrameworkException {
  
  		for (final Node child : document.getChildren()) {
  
  			if (child instanceof OperationDefinition) {
  
  				final OperationDefinition operationDefinition = (OperationDefinition)child;
  				final SelectionSet selectionSet               = operationDefinition.getSelectionSet();
  
  				for (final Selection selection : selectionSet.getSelections()) {
  
  					if (selection instanceof Field) {
  
  						queries.add(new GraphQLQuery(securityContext, (Field)selection));
  
  					} else {
  
  						logger.warn("Unknown selection set element {} in GraphQL query, ignoring.", selection.getClass());
  					}
  				}
  
  			} else {
  
  				logger.warn("Unknown document element {} in GraphQL query, ignoring.", child.getClass());
  			}
  		}
  	}
docs: ----- private methods -----