(Java) 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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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // All Chilkat classes can be unlocked at once at the beginning of a program
    // by calling UnlockBundle.  It requires a Bundle unlock code.
    CkGlobal chilkatGlob = new CkGlobal();
    boolean success = chilkatGlob.UnlockBundle("Anything for 30-day trial.");
    if (success != true) {
        System.out.println(chilkatGlob.lastErrorText());
        return;
        }

    CkMailMan mailman = new CkMailMan();

    // Set the POP3 server's hostname
    mailman.put_MailHost("pop.someMailServer.com");

    // Set the POP3 login/password and any other requirements..
    mailman.put_PopUsername("myLogin");
    mailman.put_PopPassword("myPassword");
    mailman.put_PopSsl(true);
    mailman.put_MailPort(995);

    // Connect to the POP3 server:
    CkTask task = mailman.Pop3BeginSessionAsync();
    if (mailman.get_LastMethodSuccess() == false) {
        System.out.println(mailman.lastErrorText());
        return;
        }

    // Start the background task.
    success = task.Run();
    if (!success) {
        System.out.println(task.lastErrorText());

        return;
        }

    // Wait for the POP3 connect task to finish.
    // The true/false returned by Wait applies to the Wait method call, not the task.
    int maxWaitMs = 30000;
    success = task.Wait(maxWaitMs);
    if (!success || (task.get_StatusInt() != 7) || (task.get_TaskSuccess() != true)) {
        if (!success) {
            // The task.LastErrorText applies to the Wait method call.
            System.out.println(task.lastErrorText());
            }
        else {
            // The ResultErrorText applies to the underlying task method call (i.e. the Pop3BeginSession)
            System.out.println(task.status());
            System.out.println(task.resultErrorText());
            }

        return;
        }

    // Get the number of messages in the mailbox.
    task = mailman.GetMailboxCountAsync();

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

    success = task.Run();
    success = task.Wait(maxWaitMs);
    int numMessages = task.GetResultInt();

    if (numMessages == 0) {
        return;
        }

    CkEmail email = new CkEmail();

    int i;
    for (i = 1; i <= numMessages; i++) {

        task = mailman.FetchByMsgnumAsync(i);
        if (mailman.get_LastMethodSuccess() == false) {
            System.out.println(mailman.lastErrorText());
            return;
            }

        success = task.Run();
        success = task.Wait(maxWaitMs);
        if (!success || (task.get_StatusInt() != 7) || (task.get_TaskSuccess() != true)) {
            if (!success) {
                // The task.LastErrorText applies to the Wait method call.
                System.out.println(task.lastErrorText());
                }
            else {
                // The ResultErrorText applies to the underlying task method call (i.e. the FetchByMsgnum)
                System.out.println(task.status());
                System.out.println(task.resultErrorText());
                }

            return;
            }

        // 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.  

        success = email.LoadTaskResult(task);

        if (!success) {
            System.out.println(email.lastErrorText());
            return;
            }
        else {
            System.out.println(email.ck_from() + ": " + email.subject() + "\n");
            }

        }
  }
}