67. Returning Values

Just like methods, closures can return a value. In this next example, the result of the last expression is returned (the value of num1 or num2):

def max = { num1, num2 ->
    if (num1 >= num2) {
        num1
    } else if (num2 > num1) {
        num2
    }
}

println max(14, 6)

Alternatively, we can use the return statement to explicitly exit the closure and return a value:

def myClosure = { num1, num2 ->
    if (num1 >= num2) {
        return num1
    } else if (num2 > num1) {
        return num2
    }
}

println myClosure(14, 6)

Unlike a method, closures can’t explicitly define the data type of a return value. You might take a crack at Integer maxNumber = {num1, num2 -> ...} to set the return type but this statement won’t work as maxNumber doesn’t hold the result of the closure - it holds a reference to the closure.

Closure myClosure = { num1, num2 -> ...} will work as the myClosure variable is actually of the Closure data type.