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Java Java Objects (Retired) Delivering the MVP Validation

Posted by Charles Werder
Charles Werder
Courses Plus Student 742 Points

validatedFieldName

I have been looking at my code for a while, and I can't figure out where I went wrong.

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.charAt(0) != 'm') {
    throw IllegalArgumentException("There is an error");
    }
    if (!Character.isLetter(fieldName.charAt(1)) || 
        fieldName.charAt(1) != Character.toUpperCase(fieldName.charAt(1))) {
       throw IllegalArgumentException("There is an error");
    }
    return fieldName;
  }
}

3 Answers

Charles Werder
PLUS
Charles Werder
Courses Plus Student 742 Points
Charles Werder
Charles Werder
Courses Plus Student 742 Points

Oh, wow. Can't believe I forgot that. Thanks!

Stone Preston
Stone Preston
42,016 Points
Stone Preston
Stone Preston
42,016 Points

you are missing the new keyword when throwing the exception:

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.charAt(0) != 'm') {
    throw new IllegalArgumentException("There is an error");
    }
    if (!Character.isLetter(fieldName.charAt(1)) || 
        fieldName.charAt(1) != Character.toUpperCase(fieldName.charAt(1))) {
       throw new IllegalArgumentException("There is an error");
    }
    return fieldName;
  }

however, there is a Character class method called isUpperCase that greatly simplifies the second check:

    if (!Character.isUpperCase(fieldName.charAt(1))) {
       throw new IllegalArgumentException("There is an error");
    }

see the documentation on the Character class for more helpful methods

Jess Sanders
Jess Sanders
12,086 Points
Jess Sanders
Jess Sanders
12,086 Points 
private char validateGuess(char letter) {
    if (!Character.isLetter(letter)) {
      throw new IllegalArgumentException("A letter is required."
    }
    letter = Character.toLowerCase(letter);
    if (mMisses.indexOf(letter) >= 0 || mHits.indexOf(letter) >= 0) { 
      throw new IllegalArgumentException(letter + " has already been guessed")           }
    return letter;
  }

  • The above code is the example to follow.

  • In pseudocode, we want to check for the following condition, and throw an error: " if the character at index 0 of fieldName does not equal 'm' OR the character at index 1 of fieldName is not upper case"