|LCG Project | LCG Applications Area|
|LCG Application Area Workbook||
$Date: 2004/06/28 11:16:36 $
This page explains the basic concepts of the SEAL component model. For more practical documentation, the user can directly refer to how to create new component page.
A hierarchy of bases classes has been designed to support the component model. The users adopting to model will have to inherit their own classes from of the of the classes to be compliant to the model. See the simplified class diagram.
Each Component of the application is placed in a Context at creation time. Contexts provide location functionality by Type or by a ContextKey within the running application and they are organized in a tree-like structure. In this way, if a given Component is not found in the Local Context it will look automatically for it in the parent Context in a recursive manner. A Service is Component that provides it own local Context. The next diagram shows the way to structure an application with a network of Services, Components and Contexts.
By default Components can also Plug-ins hence can be loaded dynamically as any other plug-in.