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The ServerRequest pseudo-object captures the explicit state of a request for the DSI, analogous to the Request pseudo-object
in the DII. The object adapter dispatches an invocation to a DSI-based object implementation by passing an instance of ServerRequest
to the DIR associated with the object implementation. The following shows how it provides access to the request information:
module CORBA {
...
interface ServerRequest { // PIDL readonly attribute Identifier operation; void arguments(inout NVList nv); Context ctx();
void set_result(in Any val); void set_exception(in Any val);
};};
The identity and/or reference of the target object of the invocation is provided by the object adapter and its language mapping.
In the context of a bridge, the target object will typically be a proxy for an object in some other ORB.
The operation attribute provides the identifier naming the operation being invoked; according to OMG IDL's rules, these names
must be unique among all operations supported by the object's “most-derived? interface. Note that the operation names for
getting and setting attributes are _get_<attribute_name> and _set_<attribute_name>, respectively. The operation attribute
can be accessed by the DIR at any time.
Operation parameter types will be specified, and “in? and “inout? argument values will be retrieved, with arguments. Unless
it calls set_exception, the DIR must call arguments exactly once, even if the operation signature contains no parameters.
Once arguments or set_exception has been called, calling arguments on the same ServerRequest will result in a BAD_INV_ORDER
system exception with standard minor code 7. The DIR must pass in to arguments an NVList initialized with TypeCodes and Flags
describing the parameter types for the operation, in the order in which they appear in the IDL specification (left to right).
A potentially-different NVList will be returned from arguments, with the “in? and “inout? argument values supplied. If it
does not call set_exception, the DIR must supply the returned NVList with return values for any “out? arguments before returning,
and may also change the return values for any “inout? arguments.
When the operation is not an attribute access, and the operation's IDL definition contains a context expression, ctx will
return the context information specified in IDL for the operation. Otherwise it will return a nil Context reference. Calling
ctx before arguments has been called or after ctx, set_result, or set_exception has been called will result in a BAD_INV_ORDER
system exception with standard minor code
8.
The set_result operation is used to specify any return value for the call. Unless set_exception is called, if the invoked
operation has a non-void result type, set_result must be called exactly once before the DIR returns. If the operation has
a void result type, set_result may optionally be called once with an Any whose type is tk_void. Calling set_result before
arguments has been called or after set_result or set_exception has been called will result in a BAD_INV_ORDER system exception
with standard minor code 8. Calling set_result without having previously called ctx when the operation IDL contains a context
expression will result in a MARSHAL system exception with standard minor code 2. If the NVList passed to arguments did not
describe all parameters passed by the client, it may result in a MARSHAL system exception with standard minor code 3.
The DIR may call set_exception at any time to return an exception to the client. The Any passed to set_exception must contain
either a system exception or one of the user exceptions specified in the raises expression of the invoked operation’s IDL
definition. Passing in an Any that does not contain an exception will result in a BAD_PARAM system exception with standard
minor code 21. Passing in an unlisted user exception will result in either the DIR receiving a BAD_PARAM system exception
with standard minor code 22 or in the client receiving an UNKNOWN system exception with standard minor code 1.
See each language mapping for a description of the memory management aspects of the parameters to the ServerRequest operations.