1. Software Architecture in Practice
Exercise H1 Architectural Description
TM16

2. Provided: TM16 report template TM16 source code LaTeX  Java
Ant build mgt. system
Ivy dep. mgt. system
Review the README
Try it out – ’ant help’
Inspect source code
H B Christensen

3. Case - Challenges (Our research: www.net4care.org)
Demographic challenges
2009: 70% of public health expenditure goes to chronic diseases
2040: 100% more elderly
Geographical challenges
Larger, fewer hospitals
Fewer general practitioners
Leads to a need for telemedical solutions
ICT-supported healthcare services where some of the people participating in service delivery are not co-located with the receiver of the service
(Our research:
H B Christensen

4. Vision Vision Motivation
Replace out-patient visits by measurements made by patients in their home
Move data from home to regional/national storage so all health care personal can view them...
Motivation
Reduce out-patient visits
Better quality of life
Cost savings
Better traceability and visibility
H B Christensen

5. Use case 1 2) BP measurement stored as HL7 document
1) Inger measures her BP using her TM16 terminal
H B Christensen

6. Use case 2 2) Query for all BP documents associated with Inger
1) GP queries last month’s BP measurements for Inger using web browser
H B Christensen

7. (What is XDS) Cross-Enterprise Document Sharing Think
One Registry + Multiple Repositories
Repository: Stores clinical documents
(id,document) pairs
Registry: Stores metadata with document id
Metadata (cpr, timeinterval, physician, measurement type,...)
Id of associate document and its repository
Think
Registry = Google (index but no data)
Repository = Webserver (data but no index)
H B Christensen

8. (What is HL7)
HL7 is a standard (complex!) for clinical information storage and exchange.
Version 3 loves XML!
Our version:
Real version:
H B Christensen

9. Demo Start a server Send an obs. GP review in browser ant server
ant home
GP review in browser
Use case 1
Use case 2

10. Henrik Bærbak Christensen
Demo 2
ifconfig eth0
Can talk remotely
Fire up a new machine, note its IP
ant home –Dhost=
Henrik Bærbak Christensen

11. Skeletal system TM16.zip Tool chain - choose:
Download and unzip Now you can read
Get tool chain Now you can execute
Tool chain - choose:
VM path: Get the fully working virtual machine
Manual path:
Install all tools on your local machine
Ensure they are correctly installed
View the Tools web page...
H B Christensen

12. Henrik Bærbak Christensen
Getting Started
I actually recommend using the VM
In particular if you are not core Java developer
Docker is bit tricky on Mac and Win machines
Getting TM16 up and running
Review the screencasts, links on weekplan!
Henrik Bærbak Christensen

13. Henrik Bærbak Christensen
Tool chain
Java programming language
Lots of tutorials on the web, use them
Ant build management
Probably you do not need to change it
‘ant server’, ‘ant home’, …
Ivy dependency management
Automatically download all dependencies
Review the screencasts on the weekplan
Henrik Bærbak Christensen

14. Henrik Bærbak Christensen
IDE
I stick to Eclipse even though many say IntelliJ is better
Review screencasts on weekplan
Importing TM16 + Updating once dependencies are changed
Please, adhere to this rule
Source files encoded in UTF-8
(not default on Windows!)
Indent using spaces!
Preferences -> java -> code style -> formatter
Create new profile
Pane ‘indentation’
Henrik Bærbak Christensen

15. Henrik Bærbak Christensen
Code structure
Baerbak projects
src = Production code
test = Junit test code
Run tests
Right click ‘test’ package
Run As -> JUnit Test
Screencast ‘import into eclipse’
Henrik Bærbak Christensen

16. Henrik Bærbak Christensen
Dependency Injection
I have written a book on Flexibility
Program to interface
Role is expressed by interface
Favour Object Composition
Small services collaborate to form whole
Dependency injection
The services you collaborate with are provided to you (injected)
Henrik Bærbak Christensen

17. Henrik Bærbak Christensen
Example
TeleMed : Role of a tele medicine system/server
XDSBackend: Role of an XDS database system
Xds is injected into the telemed
I can configure any suitable variant of the system by selecting the right implementations of roles to inject!
Henrik Bærbak Christensen

18. Henrik Bærbak Christensen
Test Doubles
I have written a book on Reliability
Test Doubles
Replacements for real ‘depended-on units’ that are under test control
Test cases in JUnit
Inject test doubles instead of ‘real’ units to ease and control testing
Henrik Bærbak Christensen

19. Henrik Bærbak Christensen
Example
XDSBackend: Role of an XDS database system
FakeObjectXDSDatabase: A fake test double
No persistence, all in-memory!
I can test TeleMed code without starting a real XDS database server; it is much faster and initial state is well-defined = empty database
Henrik Bærbak Christensen

20. TM16 served another purpose
Broker
TM16 served another purpose

21. Distributed Computing
I am writing the 2nd edition of my book on Distributed Computing
Broker pattern ?
Henrik Bærbak Christensen

22. Henrik Bærbak Christensen
FRS 2nd Edition
Broker
Henrik Bærbak Christensen

23. Henrik Bærbak Christensen
Broker
Example
TeleMed implementation is on machine ‘server’
On client we want to call
teleMed.processAndStore( myBloodPressure );
But networks only have
send(address, byte[]);
Byte[] receive();
Henrik Bærbak Christensen

24. Henrik Bærbak Christensen
Client Side Broker
Broker dynamics on Client side
ClientProxy:
Implements TeleMed interface
Convert every call into requests to the Requestor
Requestor:
Does marshaling = convert data to byte array format
Typically JSON or XML
ClientRequestHandler
Binds to the OS and particular network protocol
Sockets, HTTP, Messaging
Does the ‘send(payload) and blocks until answer returned
Henrik Bærbak Christensen

25. Henrik Bærbak Christensen
Server Side Broker
Broker dynamics on Server side
ServerRequestHandler:
Binds to the OS and network protocol
Receives payload from ClientRequestHandler
Invoker:
Demarshals byte[] into parameters
Dispatches to proper method and proper servant object
Servant:
Implements TeleMed interface
The real implementation!
Henrik Bærbak Christensen

26. Henrik Bærbak Christensen
Why all the trouble?
Now we can configure our own Broker system
A HTTP based client
And HTTP webserver based server
See the TM16 code for a socket based variant
Henrik Bærbak Christensen

27. Unit Testing Distribution!
Why code the broker myself?
One big advantage:
Test doubles
Now single VM system!
Henrik Bærbak Christensen

28. Henrik Bærbak Christensen
Remember: Roles
They are all roles
One object may play several
In REST and HTTP you often merge e.g. ServerRequestHandler and Invoker
Because typically you use
HTTP verbs, GET, POST, PUT, = operation names
Routes /bp/pid01 = object identifiers
Thus embody responsibilities from both roles…
Henrik Bærbak Christensen

29. Henrik Bærbak Christensen
In TM16
In the documentation exercise next (H1) do not spend an awful lot of energy on the Broker part
Early release of my book chapters are on the course web page
Henrik Bærbak Christensen

30. Henrik Bærbak Christensen
Exercise H1
Henrik Bærbak Christensen

31. Exercise H1 Document the Module viewpoint C&C viewpoint
Rather mechanically
Find packages and classes
But what to abstract and what not?
Hint: Broker is detailed elsewhere 
C&C viewpoint
What does it do?
Deployment viewpoint
The ’real’ production deployment
The +1
Architectural significant scenarios
H B Christensen

32. Digging in... Where to start? Learning tests! Manual tests!
Lots of code, many variants
Learning tests!
TestScenario.java
Manual tests!
Review build.xml
H B Christensen

33. Important TM16 is somewhat large ! Beware: Discuss, ask questions
Much code is not really architectural!
Do not dispair but keep me informed!!!
Use the web forum
Discuss, ask questions
H B Christensen