Groovy: Detecting when being passed arrays - groovy

Question

The function f in the following code simply attempts to print out it's arguments and how many it receives. However, it expands array parameters (but not arraylists) as illustrated on the line f(x) // 3. Is there anyway to get f not to expand array parameters, or alternatively at the very least detect that it has happened, and perhaps correct for it. The reason for this is because my "real" f function isn't as trivial and instead passes it's parameters to a given function g, which often isn't a variable parameter function which instead expects an array directly as an argument, and the expansion by f mucks that up.
def f = {
Object... args ->
print "There are: ";
print args.size();
println " arguments and they are: ";
args.each { println it };
println "DONE"
}
def x = new int[2];
x[0] = 1;
x[1] = 2;
f(1,2); // 1
f([1,2]); // 2
f(x); // 3

Answer 1

I doubt there is any clean solution to this, as it behaves as Java varargs. You may test the size of the array inside the closure, or, as in Java, use a method overload:
public class Arraying {
public static void main(String[] args) {
// prints "2"
System.out.println( concat( new Object[] { "a", "b" } ) );
// prints "a". Commenting the second concat(), prints "1"
System.out.println( concat( "a" ) );
// prints "3"
System.out.println( concat( "a", "b", "c" ) );
}
static String concat(Object... args) {
return String.valueOf(args.length);
}
static String concat(Object obj) { return obj.toString(); }
}
If you comment the concat(Object obj) method, all three methods will match the concat(Object... args).

Answer 2

You can use a label for the argument as follow:
def f = {
Object... args ->
print "There are: ";
print args.size();
println " arguments and they are: ";
args.each { println it };
println "DONE"
}
def x = new int[2];
x[0] = 1;
x[1] = 2;
f(1,2); // 1
f([1,2]); // 2
f(a:x); // <--- used label 'a', or anything else
then the output is:
There are: 2 arguments and they are:
1
2
DONE
There are: 1 arguments and they are:
[1, 2]
DONE
There are: 1 arguments and they are:
[a:[1, 2]]
DONE