Table 18-1 the datatypes and argument modes supported by EAServer Manager, and their corresponding CORBA IDL and ActiveX types. Each IDE script language uses a different syntax to represent these types. See your tool’s documentation for more information.
For client development, most IDEs provide some way to view the interfaces exposed by registered automation servers. If your IDE provides an object browser, you can look up the interface for the proxy object and see it displayed in the IDE’s specific syntax. For example, in Visual Basic, you can browse registered ActiveX interfaces using the Object Browser window.
For component development, you can code your component methods to use supported ActiveX datatypes, then import the DLL or type library into EAServer Manager to define the component’s IDL interface.
Argument modes specify how an argument is passed:
in – read-only; arguments are passed by value
inout – read/write; arguments are passed by reference
out – write only
return – the method returns a value of this datatype
Use in when the parameter is used to pass a value without changing the value. All parameters specified as in arguments are passed by value except for the string datatype (BSTR*). Use inout when the parameter is used to pass a value and change it. In the inout and out argument modes, the datatype of the parameter being passed must be identical to the datatype used for the same parameter in the server component method. Otherwise, no coercion is performed and an exception is thrown.
Table 18-1 the datatypes and argument modes supported by EAServer Manager, and their corresponding CORBA IDL and ActiveX types. The ActiveX column contains ActiveX datatype specification as it is defined at runtime in the ActiveX VARIANTARG structure. The ActiveX datatypes are used by OLE automation to pass data. For information on how your IDE’s datatypes correspond to these types, see your IDE’s documentation.
EAServer Manager |
CORBA IDL type |
Argument mode |
ActiveX (automation) type |
|---|---|---|---|
boolean |
boolean |
in inout out return |
VT_BOOL VT_BOOL | VT_BYREF VT_BOOL | VT_BYREF VT_BOOL |
integer<16> |
short |
in inout out return |
VT_I2 VT_I2 | VT_BYREF VT_I2 | VT_BYREF VT_I2 |
integer<32> |
long |
in inout out return |
VT_I4 VT_I4 | VT_BYREF VT_I4 | VT_BYREF VT_I4 |
float |
float |
in inout out return |
VT_R4 VT_R4 | VT_BYREF VT_R4 | VT_BYREF VT_R4 |
double |
double |
in inout out return |
VT_R8 VT_R8 | VT_BYREF VT_R8 | VT_BYREF VT_R8 |
string |
string |
in inout out return |
VT_BSTR VT_BSTR | VT_BYREF |
octet |
octet |
in inout out return |
VT_UI1 VT_UI1 | VT_BYREF VT_UI1 | VT_BYREF VT_UI1 |
binary |
BCD::Binary |
in inout out return |
VT_ARRAY | VT_UI1 (safe array) VT_ARRAY | VT_UI1 | VT_BYREF VT_ARRAY | VT_UI1 | VT_BYREF VT_ARRAY | VT_UI1 (safe array) |
decimal |
BCD::Decimal |
in inout out return |
VT_R8 VT_R8 | VT_BYREF VT_R8 | VT_BYREF VT_R8 |
money |
BCD::Money |
in inout out return |
VT_CY VT_CY | VT_BYREF VT_CY | VT_BYREF VT_CY |
date |
MJD::Date |
in inout out return |
VT_DATE VT_DATE | VT_BYREF VT_DATE | VT_BYREF VT_DATE |
time |
MJD::Time |
in inout out return |
VT_DATE VT_DATE | VT_BYREF VT_DATE | VT_BYREF VT_DATE |
timestamp |
MJD::Timestamp |
in inout out return |
VT_DATE VT_DATE | VT_BYREF VT_DATE | VT_BYREF VT_DATE |
ResultSet |
TabularResults:: ResultSet |
out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF |
ResultSets |
TabularResults:: ResultSets |
out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF |
interface (any IDL interface) |
interface |
in inout out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF VT_DISPATCH | VT_BYREF VT_DISPATCH |
structure (any IDL structure) |
See “Structure support”. |
in inout out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF VT_DISPATCH | VT_BYREF VT_DISPATCH |
enum (any IDL enum) |
in inout out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF VT_DISPATCH | VT_BYREF VT_DISPATCH |
|
typedef (any IDL type alias) |
in inout out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF VT_DISPATCH | VT_BYREF VT_DISPATCH |
|
union (any IDL union) |
See “Union support”. |
in inout out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF VT_DISPATCH | VT_BYREF VT_DISPATCH |
sequence (any IDL sequence) |
JCollection (See “Sequence support”.) |
in inout out return |
VT_DISPATCH VT_DISPATCH | VT_BYREF VT_DISPATCH | VT_BYREF VT_DISPATCH |
IDL attributes are not supported by ActiveX clients.
Because the Timestamp datatype maps to the OLE date datatype, which does not represent thousandths of a second, you could lose precision when accessing a timestamp parameter from a Java component.
ResultSet or ResultSets datatypes can only be specified as a return type.
Only byte arrays are supported—no other type of array is supported. You can also use IDL sequences in lieu of arrays. The EAServer JCollection interface is used by both clients and components to represent IDL sequences. See “Sequence support” for more information.
If you develop your component using Visual C++ and the parameter type is BSTR *, then the IDL signature for the parameter argument mode must be inout. In the IDL file, change the parameter mode to inout, regenerate and reregister the .tlb and .reg files, and modify the ActiveX client to pass the string argument by reference.
You can define get and set methods that control runtime properties for your component. However, using get and set methods to access properties over a network decreases performance.
