Graphical Editing Framework: Difference between revisions

Revision as of 09:02, 16 September 2008

Revision as of 05:05, 30 December 2008

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''Authors' Note: For the following, knowledge of [[Design Patterns]] definitely helps.''

Any user action can be seen as an example of request. The nature of request is understood by the context of invocation. For the discussion, one can safely say that the "context" is determined by the active "tool". Tool can be any entry in palette that is selected by user. We can say that, user using a tool, generates "Requests". The request is handed over to selected editpart, which inturnin turn returns an "Command".

This is achieved using [[Chain-of-responsibility pattern|Chain of responsibility]] over Editpolicies, the editpolicies determine if they can handle the request, else pass on to the next editpolicy. The order of declaration of editpolicies determine the order in which the request is passed around. The capable editpolicy creates a command. This command is handed back to the tool which initiated the "Request". Execution of the command causes the model to be modified (Response).