SnTT: Web Services that Return Arrays

Be prepared: this is a longer post than usual. I wrote my first web service the other day. I was pretty excited the first time it actually worked (if you use Visual Studio to develop, always remember to save your work before you try to test your code!). So, aside from not saving my code before testing, the thing that slowed me down the most was figuring out how to handle the data that was coming back from the web service. I was sending back an array of a user-defined class and while I found a couple of good articles (IBM ID required on this one) on writing the web service so it would return what I wanted, I couldn't find anything about how to handle it in the calling program. But now that I have figured it out, I thought I'd share with the class.

This is a scaled down version of my web service code:

Public Class OneIssue
 Public IssueNumber As String
 Public IssueTitle As String
 Public IssueDesc As String
 Public IssueStatus As String
 Public IssueTargetDate As String
 
 Sub New
  
 End Sub
 
 Sub ReadValues(doc As NotesDocument)
  IssueNumber = doc.IssueNumber(0)
  IssueTitle = doc.IssueTitle(0)
  IssueDesc = doc.IssueDesc(0)
  IssueStatus = doc.TrackingDisposition(0)
  IssueTargetDate = doc.TargetCompletion(0)
 End Sub
End Class

Public Class IssueArray
 Public MultipleIssues() As OneIssue
End Class

Public Class LOBReport
 Private session As NotesSession
 Private db As NotesDatabase
 
 Sub New
  Set session = New NotesSession
  Set db = session.CurrentDatabase
 End Sub
 
 Public Function GetIssues(OrgUnit As String) As IssueArray
  Dim dc As NotesDocumentCollection
  Dim docIssue As NotesDocument
  Dim view As NotesView
  Dim x As Integer
  
  Set GetIssues = New IssueArray
  Set view = db.GetView("ByBusUnit")
  Set dc = view.GetAllDocumentsByKey(OrgUnit)
  If Not dc Is Nothing Then
   x = 0
   Set docIssue = dc.GetFirstDocument
   While Not docIssue Is Nothing
    Redim Preserve GetIssues.MultipleIssues(x)
    Set GetIssues.MultipleIssues(x) = New OneIssue
    GetIssues.MultipleIssues(x).ReadValues(docIssue)
    x = x + 1
    Set docIssue = dc.GetNextDocument(docIssue)
   Wend
  End If
 End Function
End Class

This LotusScript was converted to HTML using the ls2html routine,
provided by Julian Robichaux at nsftools.com.

Notice the classes at the top that define a single record of the class and the array of the first class. So what do you do with that in your calling program? My front end is a "proof of concept" at this point so I used Visual Studio.net to create a small Windows program. I won't get into the details of setting up your VS.net project and referencing the web service, but this is the code that calls the web service and handles the returned value:

        Dim LOBReport As New webserverreference.LOBReportService
        Dim retval As New webserverreference.ISSUEARRAY
        Dim x As Integer
        Dim y As webserverreference.ONEISSUE
        Dim z As Integer
        Dim strings(0) As String

        TextBox1.Clear()
        z = 0
        retval = LOBReport.GETISSUES(ComboBox1.Text)
        If Not retval.MULTIPLEISSUES Is Nothing Then
            For x = 0 To UBound(retval.MULTIPLEISSUES)
                y = retval.MULTIPLEISSUES(x)
                ReDim Preserve strings(UBound(strings) + 6)
                strings(z) = "Issue Number: " + y.ISSUENUMBER
                strings(z + 1) = "Issue Title: " + y.ISSUETITLE
                strings(z + 2) = "Issue Description: " + y.ISSUEDESC
                strings(z + 3) = "Issue Status (LOB): " + y.ISSUESTATUS
                strings(z + 4) = "Issue Target Completion: " + y.ISSUETARGETDATE
                strings(z + 5) = ""
                z = z + 6
            Next
            TextBox1.Lines = strings
        Else
            TextBox1.Text = "No records found, or user not authorized for business unit"
        End If
    End Sub

At the top, I define objects of the type defined in the classes in my web service, both the single item class and the array class. Then I loop through the array and process each item in it as an instance of my single item class.

Maybe the problems I had were because I haven't used Visual Basic much, but I hope putting this out here saves someone else some time.

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