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A path to modularity with Eclipse Virgo Borislav Kapukaranov Katya Todorova March, 2012 Flickr: AbiKhairulAizad^^
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A path to modularity with Eclipse Virgo
Borislav KapukaranovKatya TodorovaMarch, 2012
Flickr: AbiKhairulAizad^^
2© 2011 SAP AG. All rights reserved. 2
In the ideal world...
A collection of modules complement each other; their sum is greater than each part. No waste, nothing to spare.
Flickr: alicejack2002
3© 2011 SAP AG. All rights reserved. 3
Benefits on the long run
Easy to maintain
Loose coupling
Clear contract
Reuse
4© 2011 SAP AG. All rights reserved. 4
The path to modularity is paved with...
No product increment
Backward compatibility issues
Risk
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Common pitfalls
Versioning Semantic versions vs reproducible build Uses clauses
Import-package vs Require-Bundle
Optional packages
Start levels How do we model core functionality?
“Google chose jetty for App engine”
http://www.infoq.com/news/2009/08/google-chose-jetty
The key features
that Jetty was
chosen for were
size and
flexibility.”
Jetty is designed to be pluggable and
extensible, so Google have been able to
customize it to a high degree.
7© 2011 SAP AG. All rights reserved. 7
Virgo in the modularity world
Standard OSGi
Bundles All the Way Down
Diagnostics ++ deadlock detection unsatisfied DS notifications extensible and independent web console extensible dump generation mechanism enhanced OSGi utilities sophisticated event logging and tracing
Virgo White Paper
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DEMO
Unsatisfied DS notifications
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Virgo Features
Nano OSGi, Diagnostics ++, DS, p2
Kernel Being good citizens in both EE and OSGi world support
(Subsystems coming) side-state resolution Virgo repositories Blueprint in the user region Load-time weaving
Tomcat Server / Jetty Server Web container
10© 2011 SAP AG. All rights reserved.
Virgo supported artifacts
Nano jar (WAB); WAR
Kernel jar; PAR; Plan, property files
Tomcat Server / Jetty Server jar (WAB), PAR; Plan; WAR, property files
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11© 2011 SAP AG. All rights reserved.
Virgo use cases
Nano Nano Base
–Equinox + Diagnostics–Embedded–Good base for OSGi apps of any kind
Nano Full–Nano Base + Web layer (+ p2)–Lightweight app server–Cloud environment
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12© 2011 SAP AG. All rights reserved.
Virgo use cases
Kernel Multi-region environment Many deployment options Clustering via Cloning Isolated and more stable core
Tomcat Server / Jetty Server Web App Servers Enterprise apps (Spring, Hibernate) Standard web apps run in OSGi
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Let me choose
Many existing apps are not OSGi aware
Often migration is not an option
Being good citizens in both EE and OSGi world is worth the effort
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Java EE 6 Web Profile
Servlet/jsp
EJB 3.1 Lite
Persistence 2.0
Transactions 1.1
CDI 1.0
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How to build a Web server from scratch?
How do we know we’ve done it right?
Does following the modularity path pays off?
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16© 2011 SAP AG. All rights reserved.
It did pay off
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Juno
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Flickr: tecnico73
Thank You!Contact information:
Borislav Kapukaranov [email protected]
@bkapukaranov
Katya Todorova [email protected]
@katiatodorova
19© 2011 SAP AG. All rights reserved.
Startup size
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Footprint
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