Hello karaf users. I have been working on what i believe to be a simplification of the configuration handling in OSGi containers. The project is slated to be able to handle different sources, but for now the the only configuration source is the felix config admin.
https://github.com/TDC-Netdesign/ManagedProperties The way it works is that you register an annotated interface, which is turned into a proxy that keeps track of the configuration for you. The proxy object is transparently updated whenever the configuration changes. It is also possible to register mappers, which can parse values into other types, for example a String to a File or an Long to an Instant. Most importantly the filters allow for validating data. This allows for checking the validity of the configuration before applying it. The MangedProperties object will revert to the last accepted configuration if a new configuration fails, eliminating the situation where the config admin holds a config set that was never applied. Two other features worth mentioning is the locking a callback functions. The properties object can lock itself, allowing any update to the configuration to be postponed. This is useful for combinations like username-password, where you do not want the configuration to change in between the calls. For example, you can lock the configuration before calling config.getUsername() and config.getPassword(). The last function is a ConfigurationCallback, that can be registered on the configuration object. When the configuration is updated the callback is called afterwards, allowing for restarts of message queues, rest clients or whatever is using the configuration but requires restarts with new configurations. I hope you will take a look at this project and use it/comment and participate, I look forward to your comments and i hope someone will find it useful. -Martin
