Question

The Java Collections class has the following method:

static <T> List<T> nCopies(int n, T o)

I need a similar method, but slightly more generic, which provides n instances of a given class. Something like:

static <T> List<T> nInstances(int n, Supplier<T> supplier)

In particular, if supplier is Supplier.ofInstance(o), we get the same behavior as the nCopies() method. Is there such a method somewhere in the Guava API?

Thank you.

Answer 1

No, but it’s easy enough to implement:

public static <T> List<T> nInstances(int n, Supplier<T> supplier){
    List<T> list = Lists.newArrayListWithCapacity(n);
    for(int i = 0; i < n; i++){
        list.add(supplier.get());
    }
    return list;
}