vwebjars - a proof of concept for java script loading in vaadin

The problem

Using java script libraries like jquery in vaadin add-ons fast leat to version conflicts, since every add-on has to ship its on version of jquery.

This is a proof of concept to solve this conflicts. The idea is to use webjars as dependencies, reference them in the add-ons and let maven solve the versions for you.

The idea

Based on the virtin webjars branch from Matti Tahvonen, some talk at the vaadin meetup in Hamburg and ideas from the vaadin forum the following things have been done:

• Pack the java script like a webjar, but without version information in the path to the *.js file
• Add a dependency to the vwebjar webjar in the addon
• Use this in a Vaadin @JavaScript annotation, but with the app://webjars protocol and prefix
• Serve the javascirpt with a thin servlet registered to the webjars path

The contents of this project

• jquery - the packed jquery version - the pom.xml is copyed from the webjars project, and modified so there is no version information in the filename
• sticky - a patched version of the Sticky Vaadin add-on using the packed jquery library webjars jquery library
• vwebjars-servlet - the servlet serving the packed java script resources,this is a dependency to the java script packages

How to try this out

Run mvn install in the parent module, and then mvn jetty:run in the sticky/sticky-demo sub module.

How to use this in your projects / add-ons?

1. Add the needed webjar as a dependency to your add-on
2. Use the @JavaScript annotation in your addon. The script name must be app://webjars/scriptFileName or app://webjars/webjarName/scriptFileName.
3. Use the vwebjars-servlet in your procejt to serve the webjars

Ideas for improvement

• Is there a way to use the original webjar *.jar, so the repacking effort is not needed?