Reasoning behind usage of Eclipse IDE in combination with OSGI bundles

English Forum
1

Hi,

For my research project at Avans University I have to find out why openEMS makes use of the Eclipse IDE in combination with OSGi-bundles. Is there anyone that could tell me the reasoning and strategy behind this.

Thank you

2

Dear Arshiya,

Thanks for getting in touch. The decisions can be broken down like this:

  1. Choice of Java as programming language
    Java was chosen, because it is a widely used, type safe programming language. Compared to alternatives like C or C++ it has some downsides in hard realtime applications, which are per definition outside of the scope of OpenEMS (we consider realtime tasks to be executed on a different system level, like e.g. on a battery management system or the firmware of an inverter.). Compared to alternatives like Python or JavaScript/NodeJS, Java has the benefit of being type safe.

  2. Choice of the OSGi module system
    As being the most advanced framework for modular systems in Java, OSGi was a natural choice:

  • An energy system is frequently composed of different hardware devices and different control algorithms have to be applied. This fits well with OSGi bundles that allow a system to be tailored with exactly the drivers and algorithms required.
  • Physical hardware is different, but often they are of the same ‘type’, e.g. a Meter or an Electric Vehicle Charging Station. In OpenEMS we call this a ‘Nature’ and it fits well with the service and provider architecture in OSGi.
  • OpenEMS code base is huge (about 500.000 lines of code) and many developers are working on it. The strict separation of interface and implementation in OSGi helped to keep a clean and structured code base, avoiding spaghetti code
  • Choosing OSGi for OpenEMS was heavily inspired by Eclipse SmartHome / OpenHAB, which already used OSGi before successfully.
  1. Choice of the Eclipse IDE
    While it is definitely possible to develop Java/OSGi applications in any other IDE (a minority of OpenEMS developers uses IntelliJ IDEA), OSGi is just best supported in Eclipse IDE together with bndtools.

Hope this helps.

Regards,
Stefan

(btw: I realized a colleague of yours also contacted the OpenEMS Association chair. For community questions we usually prefer to answer them here in the OpenEMS Community forum, as it also serves as a documentation for future readers. If you use OpenEMS at University, please consider becoming a member of the OpenEMS Association (it’s free for universities) and use our Zenodo-ID for publications)

1 Like