Learning Concurrency in Kotlin

Iterators

Iterators are particularly useful to go through a collection of elements in order. Some characteristics of Kotlin's iterators are:

• They can't retrieve an element by index, so elements can only be accessed in order
• They have the function hasNext(), which indicates whether there are more elements
• Elements can be retrieved in a single direction only; there's no way to retrieve previous elements
• They can't be reset, so they can only be iterated once

To create a suspending iterator, we use the builder buildIterator(), passing it a lambda with the body of the iterator. This will return an Iterator<T> where T will be determined by the elements that the iterator yields, unless otherwise specified:

val iterator = buildIterator {    yield ...