code: private String getIdValue(Object source) throws IllegalAccessException {
  		Field idField = configuration.getIdField(source.getClass());
  		ResourceIdHandler handler = configuration.getIdHandler(source.getClass());
  
  		return handler.asString(idField.get(source));
  	}
docs: Reads @Id value from provided source object.
  
  @param source object to read @Id value from
  @return {@link String} id or <code>null</code>
  @throws IllegalAccessException