Refactoring if/else logic

Question

I have a java class with a thousand line method of if/else logic like this:

if (userType == \"admin\") {
     if (age > 12) {
          if (location == \"         


        

Answer 1

First - use enums for userType and location - then you can use switch statements (improves readability)

Second - use more methods.

Example:

switch (userType) {
  case Admin: handleAdmin(); break;
  case Student: handleStudent(); break;
}

and later

private void handleAdmin() {
  switch (location) {
    case USA: handleAdminInUSA(); break;
    case Mexico: handleAdminInMexico(); break;
  }
}

Further, identify duplicate code and put it in extra methods.

EDIT

If someone forces you to code Java without enums (like you're forced to use Java 1.4.2), use 'final static's instead of enums or do something like:

  if (isAdmin(userType)) {
    handleAdmin(location, age);
  } else if (isStudent(userType)) {
    handleStudent(location, age));
  }

//...

private void handleAdmin(String location, int age) {
  if (isUSA(location)) {
    handleAdminInUSA(age);
  } else if (isUSA(location)) {
    handleAdminInMexico(age);
  }
}

//...

private void handleAdminInUSA(int age) {
  if (isOldEnough(age)) {
    handleAdminInUSAOldEnough();
  } else if (isChild(age)) {
    handleChildishAdminInUSA(); // ;-)
  } //...
}