| Frameworks have become popular in the object-oriented community because they offer a high level of reuse. Development based on frameworks started during the early days of Object-Oriented programming, 30 years ago. Still, framework based development is not fully understood. One of the underexplored areas is the systematic use of frameworks to extend other existing frameworks.;Frameworks are frequently used to create or extend programs but they are not frequently use to implement the features that can extend the functionality of another existing framework. We found that when the extended software is a framework, using frameworks is harder than the case when a program is extended with new functionality. However, when frameworks are described using concerns that make explicit their customizations, extensions, configurations and flows of control issues, it is possible to develop and reuse frameworks in a more productive way. Using these concerns, developers can focus on what needs to be changed and tools can be developed that check the consistency of the changes.;This dissertation presents an approach to document and build complex framework architectures by extending a framework using another existing framework. The result of the extension development is a Layered Architecture where layers are frameworks. We named the result Layered Framework Architectures. |
