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Learning Reactive Programming With Java 8

You're reading from   Learning Reactive Programming With Java 8 Learn how to use RxJava and its reactive Observables to build fast, concurrent, and powerful applications through detailed examples

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Product type Paperback
Published in Jun 2015
Publisher Packt
ISBN-13 9781785288722
Length 182 pages
Edition 1st Edition
Languages
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Author (1):
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Nickolay Tzvetinov Nickolay Tzvetinov
Author Profile Icon Nickolay Tzvetinov
Nickolay Tzvetinov
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Table of Contents (10) Chapters Close

Preface 1. An Introduction to Reactive Programming FREE CHAPTER 2. Using the Functional Constructions of Java 8 3. Creating and Connecting Observables, Observers, and Subjects 4. Transforming, Filtering, and Accumulating Your Data 5. Combinators, Conditionals, and Error Handling 6. Using Concurrency and Parallelism with Schedulers 7. Testing Your RxJava Application 8. Resource Management and Extending RxJava Index

Caching data with Observable.cache


We can use caching to cache the response in the memory and then, on the next subscription, instead of requesting the remote server again, to use the cached data.

Let's change the code to look like this:

String url = "https://api.github.com/orgs/ReactiveX/repos";
Observable<ObservableHttpResponse> response = request(url);

System.out.println("Not yet subscribed.");
Observable<String> stringResponse = response
.flatMap(resp -> resp.getContent()
.map(bytes -> new String(bytes)))
.retry(5)
.cast(String.class)
.map(String::trim)
.cache();

System.out.println("Subscribe 1:");
System.out.println(stringResponse.toBlocking().first());

System.out.println("Subscribe 2:");
System.out.println(stringResponse.toBlocking().first());

The cache() operator called at the end of the stringResponse chain will cache the response represented by a string for all the following subscribers. So, the output this time will be:

Not yet subscribed.
Subscribe 1:
main :...
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