Reactive Programming - Efficient Server Applications

The second part of the presentation for "Hack Your Career" event organized by SAP Hybris company at Silesian University of Technology in Gliwice, Poland

Slides are supportive for further live coding.
Code samples from this part the presentation are available at:
- https://github.com/pwittchen/reactive-client-server
- https://github.com/pwittchen/java-flow-experiments

Transcript

1. INTERNAL
   Piotr Wittchen, Arkadiusz Galwas, SAP Hybris
   Reactive Programming
   Efficient Server Applications
   

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2. Let’s plan an application
   

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3. 3
   INTERNAL
   © 2017 SAP SE or an SAP affiliate company. All rights reserved. ǀ
   Basic application flow
   Client
   Data Acquisition
   Reading data from sensors.
   Client
   Sending Data
   Sending data from the Client
   to the Server over HTTP
   protocol.
   Server
   Data Handling
   Handling incoming data
   received from the Client.
   Server
   Data Processing
   Processing handled data and
   logging them.
   

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4. 4
   INTERNAL
   © 2017 SAP SE or an SAP affiliate company. All rights reserved. ǀ
   Flow of the data streams inside the application
   1
   Stream
   of Sensor Events
   Data
   acquired
   on
   a
   m
   obile
   device
   2
   Stream
   of HTTP
   Requests
   Data
   sent from
   the
   client to
   the
   server
   3
   Stream
   of HTTP
   Responses
   Data
   received
   by
   the
   server
   Continuous stream of the data without breaking a chain
   

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5. 5
   INTERNAL
   © 2017 SAP SE or an SAP affiliate company. All rights reserved. ǀ
   Technologies we are going to use
   ● Server
   ○ Gradle
   ○ Java 9
   ○ RxJava 2
   ○ Vert.x
   ■ Core
   ■ Rx
   ○ Logback
   ● Client
   ○ Gradle
   ○ Android
   ○ Java 7
   ○ Retrolambda
   ○ RxJava 2
   ○ RxAndroid
   ○ OkHttp 3
   ○ ReactiveSensors
   Side note
   This is just a simple demo with the only one endpoint.
   For more endpoints it’s better to use
   Vertx-web on the server and Retrofit on the client.
   

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6. Let’s make an application!
   

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7. 7
   INTERNAL
   © 2017 SAP SE or an SAP affiliate company. All rights reserved. ǀ
   Source code of this project can be found at:
   https://github.com/pwittchen/reactive-client-server/
   

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8. Optimizing CPU usage with RxJava
   

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9. 9
   INTERNAL
   © 2017 SAP SE or an SAP affiliate company. All rights reserved. ǀ
   Optimizing CPU usage
   Core Core
   thread thread thread thread
   If we are not using all available cores efficiently, we’re wasting resources and applications are getting slow.
   CPU
   

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10. View Slide

11. 11
    INTERNAL
    © 2017 SAP SE or an SAP affiliate company. All rights reserved. ǀ
    Source code of this project can be found at:
    https://github.com/pwittchen/java-flow-experiments
    

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12. Thank you
    Contact information:
    Piotr Wittchen, Arkadiusz Galwas
    piotr.wittchen@sap.com, arkadiusz.galwas@sap.com
    Software Developers
    SAP Hybris
    

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