The Unity Application Block is a lightweight, flexible, and extensible dependency injection container that supports interception and various injection mechanisms such as constructor, property, and method call injection. The Unity Block is a standalone open source project, which can be leveraged in our application. This block allows us to develop loosely coupled, maintainable, and testable applications. Enterprise Library leverages this block for wiring the configured objects. More information on the Unity block is available at http://unity.codeplex.com; the Unity block is not covered in this book.

The Policy Injection Application Block is included in this release of Enterprise Library for backwards compatibility and policy injection is implemented using the Unity interception mechanism. This block provides a mechanism to change object behavior by inserting code between the client and the target object without modifying the code of the target object. The Policy Injection block is not covered in this book.