Chapter 11. Component models and frameworks

So far in this book, we’ve shown you how to develop applications using the core OSGi framework layers: module, lifecycle, and service. In chapter 2, we mentioned the similarities between module- and component-oriented programming. In chapter 4, we mentioned how the OSGi service model can work alongside component models. There’s obviously some degree of synergy between OSGi and component technologies. This has led a variety of existing component technologies to integrate with OSGi as well as a variety of new component frameworks being built on top of it.

Component-oriented approaches have become incredibly popular in Java development over the past decade, and a vast number of approaches are available, including Enterprise JavaBeans (EJB), Spring Beans, Google Guice, Service Component Architecture (SCA), and Fractal, to name just a few. The variety and variation among component-oriented approaches is staggering, but one thing is typically common: they ignore or only pay lip service to modularity issues related to deployment and execution-time verification and enforcement. This means OSGi technology provides a perfect foundation for integrating existing component approaches or defining new ones.

11.1. Understanding component orientation

11.2. OSGi and components

11.3. Declarative Services

11.4. Summary