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Java Java Objects (Retired) Delivering the MVP Validation

Steve Kinsey
Steve Kinsey
4,463 Points

Having problems checking for valid member variable names :-(

Been trying to get this working for ages and have tried a few different ways but still no joy.

I also think I might now be over-complicating the code.

Anyone know if I might be on the right lines with this?

Cheers Treehousers :-)

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
    char firstLetter = fieldName.charAt(0);
    if (firstLetter !='m') {
      throw new IllegalArgumentException("Must start with 'm' please"); 
    }
    char secondLetter = fieldName.charAt(1);
      boolean isSecondLetterCapital  = Character.isUpperCase(char secondLetter);
    if  (!isSecondLetterCapital)   
     {
     throw new IllegalArgumentException("2nd letter must be a capital please"); 
    }
    return fieldName;
  }
}

3 Answers

You've pretty much got it!

The problem is on this line:

boolean isSecondLetterCapital  = Character.isUpperCase(char secondLetter);

You're declaring a new char to pass into Character.isUpperCase (which is a syntax error) rather than using the one you created on the previous line.

Steve Kinsey
Steve Kinsey
4,463 Points

So something like...

char secondLetter = fieldName.charAt(1);

if(secondLetter != Character.isUpperCase(secondLetter) || !Character.isLetter(secondLetter)){

???

Just drop the char in your call to isUpperCase in the code you posted originally and it should work.

Steve Kinsey
Steve Kinsey
4,463 Points

Doh, of course, what a simple error to be melting my head for so long!!!

We got green though :-)

Thanks as ever for taking the time mrben, I really appreciate it...you just saved my head from java meltdown!!!

Peace