code: private IRI getLiteralPropertyIRI(Attribute attr) {
          return rdfFactory.createIRI(baseIRI + R2RMLIRISafeEncoder.encode(attr.getRelation().getID().getTableName())
                  + "#" + R2RMLIRISafeEncoder.encode(attr.getID().getName()));
      }
docs: Generate an URI for datatype property from a string(name of column) The
  style should be "baseIRI/tablename#columnname" as required in Direct
  Mapping Definition
  
  A column in a table forms a literal property IRI:
  
  Definition literal property IRI: the concatenation of:
  - the percent-encoded form of the table name,
  - the hash character '#',
  - the percent-encoded form of the column name.