Checking if a collection is null or empty in Groovy

Question

I need to perform a null or empty check on a collection; I think that !members?.empty is incorrect. Is there a groovier way to write the following?

if (members && !members.empty) {
    // Some Work
}

Answer 1

There is indeed a Groovier Way.

if (members) {
    //Some work
}

does everything if members is a collection. Null check as well as empty check (Empty collections are coerced to false). Hail Groovy Truth. :)

Answer 2

FYI this kind of code works (you can find it ugly, it is your right :) ) :

def list = null
list.each { println it }
soSomething()

In other words, this code has null/empty checks both useless:

if (members && !members.empty) {
    members.each { doAnotherThing it }
}

def doAnotherThing(def member) {
  // Some work
}

Answer 3

!members.find()

I think now the best way to solve this issue is code above. It works since Groovy 1.8.1 http://docs.groovy-lang.org/docs/next/html/groovy-jdk/java/util/Collection.html#find(). Examples:

def lst1 = []
assert !lst1.find()

def lst2 = [null]
assert !lst2.find()

def lst3 = [null,2,null]
assert lst3.find()

def lst4 = [null,null,null]
assert !lst4.find()

def lst5 = [null, 0, 0.0, false, '', [], 42, 43]
assert lst5.find() == 42

def lst6 = null; 
assert !lst6.find()