Extendbes

Extendbes is a software framework that facilitates the dynamic extension of behavior-based systems. It was first introduced in 2014 by a group of researchers at the University of Zurich as part of the Behavioral Extension Project. The core idea is to separate core functionality from extension modules, allowing developers to add new behavior without modifying existing code. Extendbes achieves this through a plugin architecture that uses service descriptors, similar to OSGi bundles, and a lightweight dependency injection container.

The framework defines three primary components: the Runtime Engine, the Extension Manager, and the Behavior Registry. The Runtime Engine executes behaviors as state machines, while the Extension Manager loads and unloads modules at runtime, passing configuration data through a defined API. The Behavior Registry stores metadata about available behaviors, enabling introspection and serialization. Developers write extensions in Java or Kotlin, package them as JAR files, and expose a BehaviorDescriptor. The Descriptor identifies inputs, outputs, and lifecycle callbacks that the framework invokes.

Extendbes is used in academic research on autonomous robotics, particularly in multi-agent simulations, and has been adopted by several industrial applications such as adaptive HVAC control and smart lighting systems. Its modularity reduces code churn and promotes reusable behavior components. However, the framework’s reliance on reflection and dynamic class loading introduces runtime overhead, and its API can be less intuitive for developers unfamiliar with plugin architectures. Overall, Extendbes remains a niche yet valuable tool for building flexible, behavior-driven software systems.