Woodfrog: A Persistence Library for Smartfrog Components

This paper introduces Woodfrog, a library that provides persistence properties to Smartfrog com- ponents. As arctic wood frogs do to survive cold winters, our library "freezes" a component when there is a system failure so that its internal state can be recovered and the execution resumed after the fault is overcome. Moreover, as part of the "thawing" process, references to the recovered compo- nent in other system objects are transparently restored. The library is implemented in a modular way with three very distinct tasks: stable state maintenance, component recovery and reference update. All these tasks can be overwritten and implemented using different algorithms, which allows the user to choose mechanisms more suitable to the application being deployed.