Property mapper

History

Sometime at work, I was confronted with a broker used to map key-value String pairs from and to Java objects. This broker was a pain (for maintenance, and lacking scalibility) and we intended to write it from scratch for a long time.

I add a global sketch of the new architecture (I did sketch it, on a flipboard sheet, side-by-side with the previous one), and the main question that remained was how to easily perform the mapping, without sacrificing readability, maintenability and scalability.

I proposed an annotation-based solution, and wrote a proof-of-concept, which was the base of this project, and which explains the formats of some data, inspired by the particulars of the project I was designing it for. This also was the occasion for me to work with annotations of my own. Learning the basics is always useful and helps understand how a framework may work behind the scenes.

This solution was not retained (my superior preferred the mappings done explicitly in order to have a finer control on it, but I kept this project nonetheless and tried to bring it up to correct coding standards.

Warning

This project was designed as a proof-of-concept and was never used in a production environment. The test coverage suggests it works, and I would be happy to bring some support would you be to use it.

When presenting this PoC to fellow developers, I was asked if {url-dozer}[Dozer] would be a better match for my needs. I propose you check on it as it is a much more mature framework than mine, but would you be to turn back to me, I would gladly take the opportunity of making it grow.

Goal

This was designed to allow back and forth mapping between a Map<String, String> and a POJO.

The POJO's fields are to be annotated with the keys of the values to retrieve in or store to the map, so the (un)mapping engine could perform its task autonomously, converting the fields from or to Strings.

Some vocabulary

• map: convert a POJO to a Map<String, String>
• unmap: convert a Map<String, String> to a POJO