code: private String getClassName(final TypeMirror t) {
          String res = null;
  
          if (t instanceof DeclaredType) {
              final DeclaredType dt = (DeclaredType) t;
              res = ((TypeElement) dt.asElement()).getQualifiedName().toString();
          }
  
          return res;
      }
docs: Gets the class name.
  
  @param t the type
  @return the class name