Architecture

The adaptation includes three aspects as discussed in chapter :

1.

Reconfiguration

2.

Context awareness

3.

Repository

The reconfiguration consists of a suitable programming discipline, which is expressed as a design pattern. (s. section , the concept of adaptors, including the adaptor generator, and the loader). The implementation of the reconfiguration is limited to the adaptors and the loader. The design pattern must be followed by the application programmer at compilation time.

Adaptors are generated for the core and are an integrated part of the core. The loader remains encapsulated in the adaptation mechanism. It is steered by the result of the context awareness.

The context awareness delivers the result of the evaluation of the profiles to the loader, which loads the right implementation class over the network from the repository. The profiles are also loaded by the context awareness from the repository. Both the context awareness and the loader rely on the service provided by the repository.

The communication with the repository is integrated in a repository client. The context awareness and the loader send their requests as local method calls to the repository client. The repository client communicates with the repository using a proprietary subset of the hypertext transfer protocol (HTTP). The adaptation , context awareness and the loader are designed as Java classes as shown in figure .

 

Figure: Overview of adaptation architecture  

The repository is a separate program that functions as a web server for the context awareness and the loader. Both services make use of the repository client in order to translate between Java method calls and HTTP protocol elements.

The adaptor class IConfiguration_Adaptor is generated from the functionality interface IConfiguration by the adaptor generator. To the core the IConfiguration_Adaptor class offers the two methods setDiskCache() and setMemoryCache() as defined in the interface IConfiguration. In the interior it access the adaptation mechanism.