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In this case, we do (almost) nothing to the resource implementation itself. The existing Readers are used to fetch the objects identified by the service. In this case, the main cost is loss of uniform access: for each such resource, CGI we have to know how to obtain it. Presumably this will not be intolerable, especially
Shimming (DAOs)
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Peer Replacement (JPA)
User Interface
It will have been observed that nothing has been said about end user interactions with CGI services or functionality. In part, this is due to the fact that CGI is really a set of infrastructure services for application code, not the direct end-user. But it clearly implies that users in some way will have to manage the CGI service data, which primarily is the resource mappings.