(Lianja) Async Methods Returning an Object

Demonstrates how to call an asynchronous method that returns an object. This example reads email from a POP3 server using the Async versions of the Chilkat methods.

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// All Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
loChilkatGlob = createobject("CkGlobal")
llSuccess = loChilkatGlob.UnlockBundle("Anything for 30-day trial.")
if (llSuccess <> .T.) then
    ? loChilkatGlob.LastErrorText
    release loChilkatGlob
    return
endif

loMailman = createobject("CkMailMan")

// Set the POP3 server's hostname
loMailman.MailHost = "pop.someMailServer.com"

// Set the POP3 login/password and any other requirements..
loMailman.PopUsername = "myLogin"
loMailman.PopPassword = "myPassword"
loMailman.PopSsl = .T.
loMailman.MailPort = 995

// Connect to the POP3 server:
loTask = loMailman.Pop3BeginSessionAsync()
if (loMailman.LastMethodSuccess = .F.) then
    ? loMailman.LastErrorText
    release loChilkatGlob
    release loMailman
    return
endif

// Start the background task.
llSuccess = loTask.Run()
if (not llSuccess) then
    ? loTask.LastErrorText
    release loTask
    release loChilkatGlob
    release loMailman
    return
endif

// Wait for the POP3 connect task to finish.
// The .T./.F. returned by Wait applies to the Wait method call, not the task.
lnMaxWaitMs = 30000
llSuccess = loTask.Wait(lnMaxWaitMs)
if (not llSuccess or (loTask.StatusInt <> 7) or (loTask.TaskSuccess <> .T.)) then
    if (not llSuccess) then
        // The task.LastErrorText applies to the Wait method call.
        ? loTask.LastErrorText
    else
        // The ResultErrorText applies to the underlying task method call (i.e. the Pop3BeginSession)
        ? loTask.Status
        ? loTask.ResultErrorText
    endif

    release loTask
    release loChilkatGlob
    release loMailman
    return
endif

release loTask

// Get the number of messages in the mailbox.
loTask = loMailman.GetMailboxCountAsync()

// To keep the example short, we'll skip handling failures.
// The failures would be handled in the same way as shown above.

llSuccess = loTask.Run()
llSuccess = loTask.Wait(lnMaxWaitMs)
lnNumMessages = loTask.GetResultInt()
release loTask
if (lnNumMessages = 0) then
    release loChilkatGlob
    release loMailman
    return
endif

loEmail = createobject("CkEmail")

for i = 1 to lnNumMessages

    loTask = loMailman.FetchByMsgnumAsync(i)
    if (loMailman.LastMethodSuccess = .F.) then
        ? loMailman.LastErrorText
        release loChilkatGlob
        release loMailman
        release loEmail
        return
    endif

    llSuccess = loTask.Run()
    llSuccess = loTask.Wait(lnMaxWaitMs)
    if (not llSuccess or (loTask.StatusInt <> 7) or (loTask.TaskSuccess <> .T.)) then
        if (not llSuccess) then
            // The task.LastErrorText applies to the Wait method call.
            ? loTask.LastErrorText
        else
            // The ResultErrorText applies to the underlying task method call (i.e. the FetchByMsgnum)
            ? loTask.Status
            ? loTask.ResultErrorText
        endif

        release loTask
        release loChilkatGlob
        release loMailman
        release loEmail
        return
    endif

    // Each Chilkat object that can be a return value of an asynchronous task will
    // have a method named LoadTaskResult.  The object returned in the underlying
    // asynchronous method call is retrieved by calling LoadTaskResult. 

    // To say it another way: The application will provide a pre-existing object of
    // the desired return type (in this case it is an email object).  This object is
    // loaded by calling LoadTaskResult.  

    llSuccess = loEmail.LoadTaskResult(loTask)
    release loTask

    if (not llSuccess) then
        ? loEmail.LastErrorText
        release loChilkatGlob
        release loMailman
        release loEmail
        return
    else
        ? loEmail.From + ": " + loEmail.Subject + Chr(10)
    endif

next


release loChilkatGlob
release loMailman
release loEmail