code: public String getAsString(Object obj, String propertyName) {
          Object o = get(obj, propertyName);
          if (o != null) {
              return o.toString();
          } else {
              return "";
          }
      }
docs: Getter for an object property value as String
  
  @param obj The object
  @param propertyName The property
  @return The value of the property of the object as string