DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports Events Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones AWS Cloud
by AWS Developer Relations
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones
AWS Cloud
by AWS Developer Relations

Trending

  • How Agile Works at Tesla [Video]
  • 10 Traits That Separate the Best Devs From the Crowd
  • Design Patterns for Microservices: Ambassador, Anti-Corruption Layer, and Backends for Frontends
  • What Is Envoy Proxy?

Trending

  • How Agile Works at Tesla [Video]
  • 10 Traits That Separate the Best Devs From the Crowd
  • Design Patterns for Microservices: Ambassador, Anti-Corruption Layer, and Backends for Frontends
  • What Is Envoy Proxy?
  1. DZone
  2. Testing, Deployment, and Maintenance
  3. DevOps and CI/CD
  4. Async Abstractions using rx-java

Async Abstractions using rx-java

Biju Kunjummen user avatar by
Biju Kunjummen
·
Mar. 08, 15 · Interview
Like (0)
Save
Tweet
Share
8.53K Views

Join the DZone community and get the full member experience.

Join For Free
One of the big benefits in using Rx-java for me has been the way the code looks exactly the same whether the underlying calls are synchronous or asynchronous and hence the title of this entry.

Consider a very simple use case of a client code making three slow running calls and combines the results into a list:

String op1 = service1.operation();
String op2 = service2.operation();
String op3 = service3.operation();
Arrays.asList(op1, op2, op3)

Since the calls are synchronous the time taken to do this would be additive. To simulate a slow call the following is the type of implementation in each of method calls:

public String operation() {
    logger.info("Start: Executing slow task in Service 1");
    Util.delay(7000);
    logger.info("End: Executing slow task in Service 1");
    return "operation1"
}

So the first attempt at using rx-java with these implementations is to simply have these long running operations return the versatile type Observable, a bad implementation would look like this:

public Observable<string> operation() {
    logger.info("Start: Executing slow task in Service 1");
    Util.delay(7000);
    logger.info("End: Executing slow task in Service 1");
    return Observable.just("operation 1");
}
So with this the caller implementation changes to the following:

Observable<String> op1 = service1.operation();
Observable<String> op2 = service2.operation();
Observable<String> op3 = service3.operation();

Observable<List<String>> lst = Observable.merge(op1, op2, op3).toList();


See how the caller composes the results using the merge method. 

However the calls to each of the service calls is still synchronous at this point, to make the call asynch the service calls can be made to use a Thread pool, the following way:

public class Service1 {
    private static final Logger logger = LoggerFactory.getLogger(Service1.class);
    public Observable<String> operation() {
        return Observable.<String>create(s -> {
            logger.info("Start: Executing slow task in Service 1");
            Util.delay(7000);
            s.onNext("operation 1");
            logger.info("End: Executing slow task in Service 1");
            s.onCompleted();
        }).subscribeOn(Schedulers.computation());
    }
}
subscribeOn uses the specified Scheduler to run the actual operation.

The beauty of the approach is that the calling code of this service is not changed at all, the implementation there remains exactly same as before whereas the service calls are now asynchronous. If you are interested in exploring this sample further, here is a github repo with working examples.
Abstraction (computer science) Implementation Use case GitHub Merge (version control) job scheduling

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

Opinions expressed by DZone contributors are their own.

Trending

  • How Agile Works at Tesla [Video]
  • 10 Traits That Separate the Best Devs From the Crowd
  • Design Patterns for Microservices: Ambassador, Anti-Corruption Layer, and Backends for Frontends
  • What Is Envoy Proxy?

Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com

Let's be friends: