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Java Java Objects (Retired) Delivering the MVP Validation

Jasmeet Singh
Jasmeet Singh
20,145 Points
Posted by Jasmeet Singh
Jasmeet Singh
20,145 Points

fieldName.charAt(1).isLowerCase() why is this not working?

char cannot be derefrenced?

TeacherAssistant.java 
public class TeacherAssistant {

  public static String validatedFieldName(String fieldName) {
    if(fieldName.charAt(0)!='m' && fieldName.charAt(1).isLowerCase()) {
      throw new IllegalArgumentException();
    }
    // 1.  Member fields must start with an 'm'
    // 2.  The second letter in the field name must be uppercased to ensure camel-casing
    // NOTE:  To check if something is not equal use the != symbol. eg: 3 != 4
    return fieldName;
  }

}

1 Answer

Jeremy Hill
Jeremy Hill
29,567 Points
Jeremy Hill
Jeremy Hill
29,567 Points

Your were real close. I would change the '&&' to or ('||') and then I would do this afterwards:

!Character.isUpperCase(fieldName.charAt(1))

so it should look like this:

if(fieldName.charAt(0)!='m' || !Character.isUpperCase(fieldName.charAt(1))) {
      throw new IllegalArgumentException();
    }

    return fieldName;

The reason that you don't want to use ''&&' is because that is saying that the fieldname has to have both errors before it will throw an exception; when you use '||' you are setting it to throw an exception if either condition is not met.