by Michael Ludwig

1. Modern Cloud Web Architecture
based on Google Technologies
Michael Ludwig

2. Outline
1. Example Scenario
2. Involved Technologies
3. Architecture
4. Advantages of the Technology stack

3. Outline
1. Example Scenario
2. Involved Technologies
3. Architecture
4. Advantages of the Technology stack

4. We want to develop an application for …
Movie Collection Management

5. Should have …
Multiple device support

6. Should have …
Synchronization
 Central Data Management

7. Should have …
Synchronization
 Maybe Push Notifications?

8. Computer input

9. Mobile input

10. Should have …
Scaleabilty

11. Development base
Lesari

12. Goal
Extend with Cloud functionality

13. Development principle
Avoid boilerplate code

14. Outline
1. Example Scenario
2. Involved Technologies
3. Architecture
4. Advantages of the Technology stack

15. Technologies Client
Native Android devices (smartphones, tablets)
Dalvik Virtual Machine
Java Code

16. Technologies Client
PC-Browser / Mobile Browser (iPhone, Tablet)
Browser-Engine (HTML,CSS,JavaScript)
Google Web Toolkit
Java code

17. Technologies Server
Google Cloud
Google App Engine
(like) Application Server
Java code

18. Data communication
• RequestFactory Framework
– Part of GWT
– In Java libary
– Based on JSON communication
– Suited for data-oriented CRUD applications
– Automatic entity-proxying between backend and
frontend
– Lightweigt-network payloads

19. Push notifications (Android)
• C2DM Framework
– Cloud-to-Device Messaging
– Part of Android SDK
– Example project wizard in GWT Eclipse Plugin
– Designed for Google App Engine

20. Push notifications (Browser)
• Channel-API
– COMET-like protocol
– Persistent connection to client
– Could be replaced by WebSockets API (HTML5) in
the future

21. Authentification
• Google account
– Supported by Google App Engine
– Automatically integrated in Android
– Very easy to implement
– No extra user accounts needed
– Needed for C2DM

22. Data storage
• Objectify library
– Wrapper library for Google Datastore
– Datastore is a NoSQL database
– BigTable technology (whitepaper!)
– Just uses POJO
– Very straightforward to use
– No problems like with ORM
– JDO/JPA not suited for non-relational storage

23. Dependency Injection
• Google Guice
– Versions for Android runtime, GWT (GIN) and GAE
– Like an extended Factory Pattern
– Test-driven development
– Automatic dependeny management
– Extended boilerplate reduction with RoboGuice
(Android)
– Server configuration from code (GAE)
– Addionally allows Aspect-oriented programming
(AOP)

24. Outline
1. Example Scenario
2. Involved Technologies
3. Architecture
4. Advantages of the Technology stack

25. Google Cloud
Google Datastore
Objectify
C2DM Server Application Server (GAE) Guice
Channel API
Push notifications RequestFactory Push notifications
JSON JSON
Android Client Web Client (GWT)
RoboGuice Gin

26. Outline
1. Example Scenario
2. Involved Technologies
3. Architecture
4. Advantages of the Technology stack

27. Advantages
Write all code in Java

28. Advantages
Shared code

29. Advantages
Live Debugging Server and Client

30. Advantages
Easy development for many platforms

31. Advantages
Entity and proxy validation

32. Advantages
Test-driven development possible

33. Advantages
No Impedance Mismatch

34. To conclude …
Faster development
through saving a lot of boilerplate

35. References
• Android SDK Page
• GWT Official Page
• Google App Engine Official Page
• C2DM Official Page
• Google Guice Official Page
• Objectify Official Page
• Cloud-tasks-IO example project
• „Using GWT RequestFactory with Objectify“ – David Chandler
• Google I/O 2011: Android + App Engine: A Developer's Dream
Combination (Blog)

36. Questions?
• Further Information:
ludwigm@in.tum.de
• Presentation link:
http://bit.ly/ML-IS-Sem

37. Backup

38. DI demonstration
Real data Real data Test data
RichMovieInfoWidget TabletMovieInfoWidget TestMovieInfoWidget
Interface
IRichMovieInfo

39. Request factory proxies
Interface Client Server
MovieEntryProxy MovieEntry

40. Request factory services
Interface Client Server
MovieEntryRequest MovieEntryDao

41. Request factory access

42. Outlook
• GWT advantages
– MVP Framework
• Places concept
• Activities Concept
• Suitability of Guice
– Internationalization-Support
– Etc.
• Guice advantages
– Scope Management
– Custom Providers.
– Etc.