CVAL Licensing Problem


I wanted to upload a version of my Event Timeline addon under the CVAL license but was stuck somehow.
The Event Timeline is based on the original Vaadin Timeline and the plan is to make this addon also available for free to commercial projects. For this to work, people need a valid CVAL license for the Vaadin Timeline, but in the addon upload process a minimum price of 10 USD for CVAL is mentioned.

Is there a way to publish a CVAL version of my addon without requesting users to buy an additional CVAL license for it?

Thanks Thomas

Really good question. CVAL is not designed for making forking easy, while as it is not designed to specially prevent that either.

Just to walk through the easy options - even though they are not what you looking after:

  • You could fork the AGPL version of Timeline component and distribute the modified version available with AGPL license
  • If you could modify the component by extending it, you could distribute you extensions (but no parts copied from the original Timeline component) with Apache license and distribute them as you wish

The license says:

So it gives you freedom to license the Project Result - in this case EventTimeline - with whatever license you wish, BUT all licensees of EventTimeline would need also a CVAL license to Timeline. Unfortunately the license does not give guidance on how or if you should be ensuring that the users of Event Timeline really have a license to Timeline component. Distributing your component with CVAL license would not help in this respect. Furthermore, directory channel and vaadin add-on packaging mechanism does not support this either.

Some options that come into my mind:

  • An easy, but not too user-friendly, option would be to distribute EventTimeline as a patch to Timeline sources. This would make it clear for the users that they need Timeline component
  • Figure out what would it take to allow Timeline to support EventTimeline as separate extension (by inheritance). This could be as simple as making some private methods protected or small refactoring of the private methods in Timeline. Then you could contribute that refactoring as a patch to the development team behind Timeline component and ask them to integrate your patch. If done, it would make distribution and maintenance of EventTimeline easy. If this option is feasible, it would probably be the best for everyone.

Hi Joonas,

thanks for the clarification. I already forked off from the AGPL version (see
Addon entry
), but wanted to provide an additional CVAL compatible version for people who use it in commercial projects. The addon description clarifies that you need a valid Vaadin Timeline license, but I could not add a cval version of my addon as it requires at least a price of 10 USD, and I did not want to charge for it.

I guess thats a very unique case, and I can live with a agpl version, but it would be nice if this could be supported somehow.