Wro4j integration

Date	2014-01-06	Contacts	Jesse Eichar
Status	Proposed for Vote	Release	2.12
Resources	Jesse Eichar	Ticket #	https://github.com/geonetwork/core-geonetwork/issues/337
Source code	https://github.com/geonetwork/core-geonetwork/tree/javascript_build
Funding	N/A

Overview

Use Wro4j (Web Resource Optimization for Java) for Javascript develop/test/minification/build in Geonetwork.

At the moment YUI-compressor is used in web-client and web modules. Closure compiler, less and python are used in web-ui.

This makes the build process difficult and introducing new developer to the system can be confusing because they won't know what technology to use or how to debug.

We propose using Wro4J as the unified solution. Wro4J will be integrated into the build as a Servlet Filter bound to the /static/* path.

The benefits of Wro4J over the current technologies are as follows:

YUI
- YUI configuration is hardcoded in pom.xml
- Wro4j has the configuration in external file
- This means that Configuration overrides can be used in the future to modify the javascript minification build
- It also simplifies the pom files and makes the build simpler to understand
- Rebuilding the module is required for new minified files
- Wro4j minifies when a file is changed (in development mode)