gauard clause in java

Hi,

I am going through below link

http://refactoring.com/catalog/replaceNestedConditionalWithGuardClauses.html

I see below code can be modified better as given further below
double getPayAmount() {
  double result;
  if (_isDead) result = deadAmount();
  else {
    if (_isSeparated) result = separatedAmount();
    else {
      if (_isRetired) result = retiredAmount();
      else result = normalPayAmount();
    };
  }
  return result;
};  

double getPayAmount() {
  if (_isDead) return deadAmount();
  if (_isSeparated) return separatedAmount();
  if (_isRetired) return retiredAmount();
  return normalPayAmount();
};  

Open in new window


I wonder what is the meaning of 'guard clause'  what is its significance.

Please advise
LVL 7
gudii9Asked:
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ste5anSenior DeveloperCommented:
"Guard Clause" means that you exit the code by an early return, avoiding the "evaluation" of the further else parts.
0
dpearsonCommented:
You might find this example:
http://blog.mafr.de/2009/06/12/a-case-for-guard-clauses/

easier to understand.  It points out more clearly exactly what the "guard clause" is in the code.  It's "guarding" the later code from being executed, because some condition has not been met.  So you can edit the function immediately.

Hope that helps,

Doug
0
gudii9Author Commented:
double getPayAmount() {
  if (_isDead) return deadAmount();
  if (_isSeparated) return separatedAmount();
  if (_isRetired) return retiredAmount();
  return normalPayAmount();
};  

Open in new window


In above code where and how they are doing

"Guard Clause" means that you exit the code by an early return, avoiding the "evaluation" of the further else parts.

Please advise
0
zzynxSoftware engineerCommented:
What is your remaining question exactly?

These are the three guard clauses:

  if (_isDead) return deadAmount();
  if (_isSeparated) return separatedAmount();
  if (_isRetired) return retiredAmount();

Open in new window


If the variable _isDead is true, we immediately return deadAmount()
If the variable _isSeparated is true, we immediately return separatedAmount()
If the variable _isRetired is true, we immediately return retiredAmount()

That's much better readable and understandable than the first code you posted
0

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