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Java Java Objects (Retired) Delivering the MVP Validation

Posted by Gem Knight
Gem Knight
4,779 Points

I need help

I am on the course java objects and I really need help. Somebody please.

TeacherAssistant.java 
public class TeacherAssistant {

  public static String validatedFieldName(String fieldName) {
    // These things should be verified:
    // 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
    if (fieldName.indexOf(0) != 'm' || 
        fieldName.indexOf(1) >= 0 != Character.isUpperCase(fieldName.indexOf(1)))
      throw new IllegalArgumentException("Invalid fieldname entered.");
    }
    return fieldName;
  }

}

4 Answers

Jeremy Hill
Jeremy Hill
29,567 Points

You may be right, it seemed like it would have the same result. I went ahead and ran the challenge and this code worked for me:

public class TeacherAssistant {

  public static String validatedFieldName(String fieldName) {
    if(fieldName.charAt(0) != 'm'  ||  !Character.isUpperCase(fieldName.charAt(1)))
   throw new IllegalArgumentException("Invalid fieldname entered.");
else 
  return fieldName;

  }

}
Gem Knight
Gem Knight
4,779 Points

It worked

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

try replacing your indexOf() with charAt() in your if statement and you don't need the >= 0 in there.

Jeremy Hill
Jeremy Hill
29,567 Points
Jeremy Hill
Jeremy Hill
29,567 Points 
if(fieldName.chartAt(0) != 'm'  ||  Character.isLowerCase(fieldName.charAt(1)))
   throw new IllegalArgumentException("Invalid fieldname entered.");
else 
  return fieldName;

I didn't run this code but I believe it will work.

Gem Knight
Gem Knight
4,779 Points

Sorry did not work

Jeremy Hill
Jeremy Hill
29,567 Points

I just realized that I typed the first charAt wrong: I typed it chartAt(). Try it again without the extra 't'.

bzfchen
bzfchen
6,484 Points
bzfchen
bzfchen
6,484 Points

I don't think Character.isLowerCase(char) is equivalent to !Character.isUpperCase(char) in all cases.

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

return fieldName;