The Business Delegate design pattern provides an extra layer of abstraction between the presentation view and the business services, in the case of Viewpoint; this is the Viewpoint Data Collection System (DCS). A Business Delegate in a portlet would provide an interface to the Data Access Object (DAO). In addition to hiding the implementation details of the DCS, the business delegate allows the data being requested by the portlet to be cached.

See the Core J2EE page for more detail: