mapping data in properties files

Question

I have the following data:

User   System    SubSystem
user1  System1   SubSystem1
user2  System1   SubSystem2
user3  N/A       N/A

and i need to be able to determine the system/subsystem tuple from the user. I must be able to add users at any time without rebuilding and redeploying the system.

I know the database would be the best option here but I cannot use a database table.

I currently have it mapped using a hash map but I don't want it to be hard-coded. I was thinking about using a properties file but I can't visualize how I would implement it. Anyone else have any suggestion?

Not that it matters but I'm using JAVA, on weblogic 10.3.

Answer 1

I would go for something as simple as :

user1 = userValue
user1.system = systemValue
user1.system.subsystem= subsystemValue
user2 = userValue
user2.system = systemValue
user2.system.subsystem= subsystemValue

user(id) is used as "primary" key in your properties, and a very simple concatenation of your fields to store your table values. I use this very often : trust me, it's much more powerfull than it may appear :)

Answer 2

You could do this using a HashMap (as you do now) and store it using XStream.

XStream allows you to serialise/deserialise Java objects to/from readable/editable XML. You can then write this to (say) a filesystem, and the result is editable by hand.

The downside is that it's a serialisation in XML of a Java object, so not as immediately obvious as a properties file to edit. However it's still very readable, and easily understood by anyone remotely technical. Whether this is an appropriate solution depends on the audience of this file.

Answer 3

Sounds like something you could very well use YAML for..
SnakeYAML looks to be a workable Java implementation.

Answer 4

For this project i've gone with the solution proposed by Olivier. Some project contrainst (legacy of the project) prevent me for going with a probably better solution of using XStream.

Thx for the feed back guys