setter for the denied extensions of a file type . the allowed extensions will be cleared . if extensionslist is null , denied extensions are kept untouched . concode_field_sep Map<ResourceTypeHandler,Set<String>> extensionsDenied concode_elem_sep Map<ResourceTypeHandler,Set<String>> extensionsAllowed concode_field_sep boolean isAllowed concode_elem_sep void setExtensionsAllowed concode_elem_sep Set<String> getExtensionsDenied concode_elem_sep Set<String> getExtensionsAllowed