Question

I’m trying to factorize some groovy code inside a closure.

Here is a sample code illustrating what I want to do (see HibernateCriteriaBuilder)
base code:

def criteria  = Account.createCriteria()
def results = criteria  {
  if(A) {
    // full code section when A
  } 
  if(B) {
    // full code section when B
  }
  ...
  if(N) {
    // full code section when N
  }
}

Now I want to extract condition block in method to be able to use them in other criteria.
Here is the code I have now:

def criteria = Account.createCriteria()
def results = criteria  {
 a(criteria)
 b(criteria)
 ...
 n(criteria)
}
def a(criteria) { if(A) /* full code section when A */ }
def b(criteria) { if(B) /* full code section when B */ }
...
def n(criteria) { if(N) /* full code section when N */ }

Is there a groovy way to avoid to pass the criteria in the argument of each method ? (in other word, is there a way to get the calling context ?)

And, to extend this to other closure, how should I extract method from groovy closure ?

Answer 1

One possibility is to change your a, b, n methods to closures, then set their delegate property to criteria before invoking them, e.g.

def criteria = Account.createCriteria()

def results = criteria  {
   a.delegate = criteria
   a()
}

def a = { if(A) /* full code section when A */ }

This meets your requirement of avoiding the need to pass the criteria in the argument of each method, but to be honest, I don’t really see what this achieves.

The code you posted in your question is more compact and readable, in my opinion