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The processing has two parts. One part is performed by Acegi, and the other part is performed by SAIS framework Framework code.
Acegi
Acegi is a package that tries to abstract authentication and authorization processing in a manner that allows them to be customized for a particular set of requirements. For web applications, Acegi is "plugged in" as a servlet filter. If the Acegi servlet filter is configured in the web.xml then Acegi will be called on each request to the servlet.
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