Method annotation used to transform methods with tail recursive calls into iterative methods automagically since the JVM cannot do this itself. This works for both static and non-static methods.
It allows you to write a method like this:
import groovy.transform.TailRecursive
class Target {
@TailRecursive
long sumUp(long number, long sum = 0) {
if (number == 0)
return sum;
sumUp(number - 1, sum + number)
}
}
def target = new Target()
assert target.sumUp(100) == 5050
assert target.sumUp(1000000) == 500000500000 //will blow the stack on most machines when used without @TailRecursive
@TailRecursive is supposed to work in combination with @CompileStatic
Known shortcomings:
Throwable around a recursive might lead to problems
More examples:
import groovy.transform.TailRecursive
@TailRecursive
long sizeOfList(list, counter = 0) {
if (list.size() == 0) {
counter
} else {
sizeOfList(list.tail(), counter + 1)
}
}
// Without @TailRecursive a StackOverFlowError
// is thrown.
assert sizeOfList(1..10000) == 10000