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Java 8 Stream to Rx-Java Observable

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Java 8 Stream to Rx-Java Observable

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What every Java engineer should know about microservices: Reactive Microservices Architecture.  Brought to you in partnership with Lightbend.

I was recently looking at a way to convert a Java 8 Stream to Rx-JavaObservable.

There is one api in Observable that appears to do this :

public static final <T> Observable<T> from(java.lang.Iterable<? extends T> iterable)

So now the question is how do we transform a Stream to an Iterable. Stream does not implement the Iterable interface, and there are good reasons for this. So to return an Iterable from a Stream, you can do the following:

Iterable iterable = new Iterable() {
    @Override
    public Iterator iterator() {
        return aStream.iterator();
    }
};

Observable.from(iterable);

Since Iterable is a Java 8 functional interface, this can be simplified to the following using Java 8 Lambda expressions!:

Observable.from(aStream::iterator);

First look it does appear cryptic, however if it is seen as a way to simplify the expanded form of Iterable then it slowly starts to make sense.

Reference:
This is entirely based on what I read on this Stackoverflow question.


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Published at DZone with permission of Biju Kunjummen, DZone MVB. See the original article here.

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