1. “OSGi at the UK’s Biggest Science Lab.”
goo.gl/1f5HnD

2. DLS

3. Movie 1 Electron Journey
DLS

4. Movie 2 – experiment
DLS

5. MX Robots
Movie 3 – Robot Arm
DLS

6. Software Generic Data Acquisition or GDA
Java Server -> 3 million lines -> static classpath
Thick Java Client (written in RCP)
Legacy System - inherited from a previous synchrotron
‘Run from Source’ Culture
Software

7. The Creeping Cost of Support
Cost Support of Acquisition >>
Proportion of Development <<
Different APIs that do similar things
Overly Interconnected Projects and Classes
Improper Encapsulation
Poor Unit Tests
Development Coordination = Hard
Software

8. The Mapping Project nD scanning Move Sample – Not Machine
Scan Path Analysis – Run fast stuff
New file format
Multiple languages and layers
Online Analysis Required
Examples
VMXi – Automated, versatile and crystal friendly
Spectroscopy of 2D samples
Software

9. VMXi – Early Prototype Work 2015/16
Movie 4 - VMXi

10. Mapping – Early Prototype
Movie 5 – Mapping

11. Software

12. OSGi
OSGi

13. Real world problem #1: Integration
We made a single product!
OSGi = Big Footprint, Small Running Memory
Run from source hard!
Investigated and deployed JRebel
OSGi

14. Real world problem #2: Multiple configurations
Single Product : Multiple Configurations
Wanted to keep Spring
Spring makes objects after OSGi Services
OSGi breaks up classloader - Spring No Like
Solution? Eclipse Buddy which is an Equinox Feature
OSGi

15. Real world problem #3: Migrating to bundles
Modularity! >>
No more ‘core’ bundles which glue things
Bundles which use things and those which provide things
org.eclipse.scanning.server has TWO bundle dependencies
Create API bundles with NO dependencies
OSGi Services -> implement interfaces
Gradual Migration Practical Solution -> Needs Developer Participation
OSGi

16. Real world problem #4: The static, non-modular algorithm
GDA8 Scanning System
Many ‘static’ parts
Non-modular
Unable to work with new NeXus API
Slow in some cases
Not Deprecated in 9
GDA9 / Solstice Scan
Service based, Modular
Instance !Singletons
Annotations !Interfaces
NeXus API++
Fast and Scalable
Executor Based
Less Features
Malcolm
OSGi

17. Real world problem #5: Cardinality
In OSGi you have the following options for a cardinality of a service:
0..1 (meaning zero or one service instances)
0..n (meaning zero to n)
1..1 (one and if it is not available, things start to fail)
1..n (one or more)
1..1 and static can block errors injecting services in funny ways
OSGi

18. Real world problem #6: Declarative services
Do not ignore OSGi messages
Some serious
Some ignorable!!
-Dequinox.ds.print=true
0..1 cardinality for a service not yet available - Not an error
!ENTRY org.eclipse.equinox.ds :25: !MESSAGE Could not bind a reference of component Scanning Servlet Services.
OSGi

19. Real world problem #7: The hidden cost of TDD
Modularity -> Easy and Complete Unit Testing
Services easy parts to Mock out
Unit Test Examples
Scannable Service
Runnable Device (Detectors!) Service
End to end NeXus scans
1000’s new tests = BUILD PROBLEM
Modular Product + Github + Travis CI = Sub-builds, No Waiting
OSGi

20. Software Front-End Mapping
Movie 6 – Front End

21. Conclusions OSGi made Acquisition Server Modular
Service Oriented in Architecture
Fast Startup
Industry Standard
Mature, Online Help Great
Easy to do
Opportunity to increase tests
New Features Added! (Scanning + NeXus + UI)