How to make field readonly, required and set value null

By using maximo api we can make fields read-only, required and set values null to the attributes:

To make field Readonly: setFieldFlag("<attributename>",7L,true);
To make field Editable: setFieldFlag("<attributename>",7L,false);
To set value as null: setValueNull("<attributename>",2L);
To make field Required: setFieldFlag("<attributename>",8L,true);