Developing ActiveX client application code
Develop an ActiveX Windows program, such as Visual Basic, VBScript, and Active Server Pages, to use the WebSphere® ActiveX to EJB bridge to access enterprise beans.
Before you begin
Consider the information given in ActiveX to EJB bridge as good programming guidelines.
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Procedure
Example
Viewing a System.out message: The ActiveX to Enterprise JavaBeans (EJB) bridge does not have a console available to view Java System.out messages. To view these messages when running a stand-alone client program (such as Visual Basic), redirect the output to a file.
launchClientXJB.bat MyProgram.exe > output.txt
- To view the System.out messages when running a Service program such as Active Server Pages, override the Java System.out OutputStream object to FileOutputStream. For example, in VBScript:
'Redirect system.out to a file ' Assume that oXJB is an initialized XJB.JClassFactory object Dim clsSystem Dim oOS Dim oPS Dim oArgs ' Get the System class Set clsSystem = oXJB.FindClass("java.lang.System") ' Create a FileOutputStream object ' Create a PrintStream object and assign to it our FileOutputStream Set oArgs = oXJB.GetArgsContainer oArgs.AddObject "java.io.OutputStream", oOS Set oPS = oXJB.NewInstance(oXJB.FindClass("java.io.PrintStream"), oArgs) ' Set our System OutputStream to our file clsSystem.setOut oPS
ActiveX client application using helper methods for data type conversion. Generally, data type conversion between ActiveX (Visual Basic and VBScript) and Java methods occurs automatically, as described in ActiveX to EJB bridge, converting data types. However, the byte helper function and currency helper function are provided for cases where automatic conversion is not possible.
- Byte helper function Because the Java Byte data type is signed (-127 through 128) and the Visual Basic Byte data type is unsigned (0 through 255), convert unsigned Bytes to a Visual Basic Integers, which look like the Java signed byte. To make this conversion, you can use the following helper function:
Private Function GetIntFromJavaByte(Byte jByte) as Integer GetIntFromJavaByte = (CInt(jByte) + 128) Mod 256 - 128 End Function
- Currency helper function Visual Basic 6.0 cannot properly handle 64-bit integers like Java methods can (as the Long data type). Therefore, Visual Basic uses the Currency type, which is intrinsically a 64-bit data type. The only side effect of using the Currency type (the Variant type VT_CY) is that a decimal point is inserted into the type. To extract and manipulate the 64-bit Long value in Visual Basic, use code like the following example. For more details on this technique for converting Currency data types, see Q189862,
HOWTO: Do 64-bit Arithmetic in VBA
, on the Microsoft Knowledge Base.' Currency Helper Types Private Type MungeCurr Value As Currency End Type Private Type Munge2Long LoValue As Long HiValue As Long End Type ' Currency Helper Functions Private Function CurrToText(ByVal Value As Currency) As String Dim Temp As String, L As Long Temp = Format$(Value, "#.0000") L = Len(Temp) Temp = Left$(Temp, L - 5) & Right$(Temp, 4) Do While Len(Temp) > 1 And Left$(Temp, 1) = "0" Temp = Mid$(Temp, 2) Loop Do While Len(Temp) > 2 And Left$(Temp, 2) = "-0" Temp = "-" & Mid$(Temp, 3) Loop CurrToText = Temp End Function Private Function TextToCurr(ByVal Value As String) As Currency Dim L As Long, Negative As Boolean Value = Trim$(Value) If Left$(Value, 1) = "-" Then Negative = True Value = Mid$(Value, 2) End If L = Len(Value) If L < 4 Then TextToCurr = CCur(IIf(Negative, "-0.", "0.") & _ Right$("0000" & Value, 4)) Else TextToCurr = CCur(IIf(Negative, "-", "") & _ Left$(Value, L - 4) & "." & Right$(Value, 4)) End If End Function ' Java Long as Currency Usage Example Dim LC As MungeCurr Dim L2 As Munge2Long ' Assign a Currency Value (really a Java Long) ' to the MungeCurr type variable LC.Value = cyTestIn ' Coerce the value to the Munge2Long type variable LSet L2 = LC ' Perform some operation on the value, now that we ' have it available in two 32-bit chunks L2.LoValue = L2.LoValue + 1 ' Coerce the Munge value back into a currency value LSet LC = L2 cyTestIn = LC.Value