The generation of proxy implementations depends on the constructions of a given language. However, using an object-oriented language, each OMG IDL interface is implemented by a class inheriting from a base class provided by the TORBA runtime. These classes fully hide the ODP/OMG CosTrading technicity: use of the service interfaces and data structures, as well as exception handling. Such runtime classes provide generic operations used from proxy implementations. Figure 8 presents an excerpt of the lookup proxy implementation for the Printer offer type, generated for the OMG IDLscript language.
The Lookup class inherits from the TORBArt.LookupBase class provided by the TORBA runtime. The __Lookup__ constructor invokes the super-class constructor providing the TDL type name (i.e. Printer), as well as the implemented interface type (i.e. Printer::Lookup). The generic query operation is invoked by the query operation providing the constraint to apply. Then, the result is translated to a printer offer sequence (i.e. Printer::OfferSeq). The implementation of query operations, like query_faster and query_all, only consists of creating the associated constraint and invoking the query operation.
