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Java Java Objects (Retired) Delivering the MVP Validation

Posted by Thomas Katalenas
Thomas Katalenas
11,033 Points

I've added the method validatedFieldName it will return the validated field name. If the value passed in doesn't meet th

it says I can't do fieldName[0]

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[0] != 'm'){
      continue;
    }else{throw IllegalArgumentException;}


    return fieldName;
  }

}

3 Answers

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

Try the charAt() method. Call it on fieldName and pass 0 to it as the index.

Thomas Katalenas
Thomas Katalenas
11,033 Points
Thomas Katalenas
Thomas Katalenas
11,033 Points 
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')
      continue;
    if (fieldName.charAt(1) == fieldName.charAt(1).toUpperCase())
    return fieldName;
  }

}

./TeacherAssistant.java:9: error: continue outside of loop
      continue;
      ^
./TeacherAssistant.java:10: error: char cannot be dereferenced
    if (fieldName.charAt(1) == fieldName.charAt(1).toUpperCase())
                                                  ^
2 errors
Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

The continue keyword is used in loops. You need an if-else statement. In the if part check to see if fieldName doesn't start with 'm' or the second letter of fieldName is not uppercase. If that's the case you need to throw an IllegalArgumentException exception. In the else part return fieldName.

Also, you can make use of the isUpperCase() method of the Character class to see if the second letter is uppercase:

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