Using join with an iterator and a String function

Question

Suppose I have an Iterator<Class1> object. Class1 provides a method stringFunction() that returns a String.

Is there a way to use String.join in a way that calls stringFunction() on every Class1 returned by the iterator, and concatenates the function results separated by a delimiter?

There's a String.join overload that takes an Iterable<CharSequence>; is it possible to create one from the Iterator<Class1> and the stringFunction, so that join can use it?

Answer 1

How about using

• streamOfCharSequence.collect(Collectors.joining(delimiter))

instead of String.join(delimiter, Iterable<CharSequence>.

You can try something like

String result = StreamSupport
        .stream(Spliterators.spliteratorUnknownSize(iterator,
                Spliterator.ORDERED), false)
        .map(e -> e.stringFunction()).collect(Collectors.joining(", "));