Stream in Iterable

By Syed Wahaj

Introduction

Java streams provide a powerful way to work with collections of data. However, sometimes we need to convert a stream into an iterable. In this article, we’ll look at how we can convert a Java stream to an iterable in a few different ways.

Using a Collection

The simplest way to convert a Java stream to an iterable is by using a collection. We can use the collect method to collect the stream into a collection, and then return an iterator over the collection. Here’s an example:

List<String> list = Arrays.asList("foo", "bar", "baz");
Iterable<String> iterable = list.stream().collect(Collectors.toList());

In this example, we’re using a List as the collection. We’re collecting the stream into the list using the collect method and the Collectors.toList() collector. Finally, we’re returning an iterator over the list, which is an iterable.

Using a Spliterator

Another way to convert a Java stream to an iterable is by using a spliterator. A spliterator is an interface that represents a stream of elements that can be split into multiple parts for parallel processing. We can use the spliterator method to get a spliterator from a stream, and then create an iterable from the spliterator. Here’s an example:

List<String> list = Arrays.asList("foo", "bar", "baz");
Iterable<String> iterable = () -> list.stream().spliterator();

In this example, we’re creating a lambda expression that returns a spliterator from the stream. We’re then using the lambda expression to create an iterable.

Using a StreamSupport Class

Finally, we can also use the StreamSupport class to create an iterable from a Java stream. The StreamSupport class provides utility methods for working with streams, and one of these methods is the stream method, which creates a stream from an iterable. We can use this method to create an iterable from a stream. Here’s an example:

List<String> list = Arrays.asList("foo", "bar", "baz");
Iterable<String> iterable = StreamSupport.stream(list.spliterator(), false)::iterator;

In this example, we’re using the StreamSupport.stream method to create a stream from the spliterator of the list. We’re then using a method reference to create an iterator from the stream, which is an iterable.

Conclusion

Converting a Java stream to an iterable is a useful technique when we need to work with libraries or methods that require an iterable. In this article, we’ve seen three ways to convert a Java stream to an iterable, using a collection, a spliterator, and the StreamSupport class.