(Java) Async Task Chain (another example)

Demonstrates using a task chain to run a sequence of FTP tasks asynchronously.

Chilkat Java Downloads Java Libs for Windows, MacOS, Linux, Alpine Linux, Solaris Java Libs for Android

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;
        }

    CkFtp2 ftp = new CkFtp2();

    ftp.put_Hostname("ftp.someFtpServer.com");
    ftp.put_Username("****");
    ftp.put_Password("****");

    // Connect and login to the FTP server.
    success = ftp.Connect();
    if (success != true) {
        System.out.println(ftp.lastErrorText());
        return;
        }

    CkTaskChain taskChain = new CkTaskChain();

    // Create a task to change to the remote directory where the file will be uploaded.
    CkTask task = ftp.ChangeRemoteDirAsync("junk");
    if (ftp.get_LastMethodSuccess() == false) {
        System.out.println(ftp.lastErrorText());
        return;
        }

    // Add this task to the task chain.
    success = taskChain.Append(task);

    // Create a task to upload a file.
    String localFilename = "c:/temp/hamlet.xml";
    String remoteFilename = "hamlet.xml";

    task = ftp.PutFileAsync(localFilename,remoteFilename);
    if (ftp.get_LastMethodSuccess() == false) {
        System.out.println(ftp.lastErrorText());
        return;
        }

    // Add this task to the task chain.
    success = taskChain.Append(task);

    // Start the task chain running in a background thread.
    // Each task is run one after the other (on the same background thread) until all tasks have completed.
    // The task chain will stop at the first task that fails.
    taskChain.put_StopOnFailedTask(true);
    success = taskChain.Run();
    if (!success) {
        System.out.println(taskChain.lastErrorText());
        return;
        }

    // The application is now free to do anything else
    // while the FTP commands are being run...

    // For this example, we'll simply sleep and periodically
    // check to see if the taskchain if finished. 
    while (taskChain.get_Finished() != true) {

        // Sleep 100 ms.
        taskChain.SleepMs(100);

        }

    // A finished task chain could be one that was canceled, aborted, or truly finished.  

    // If the task chain "completed", then it ran to completion.  A "completed" task will
    // have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
    // been aborted or canceled:
    if (taskChain.get_StatusInt() != 7) {
        System.out.println("Task did not complete.");
        System.out.println("task chain status: " + taskChain.status());
        return;
        }

    // If we got to this point, the ChangeRemoteDir and PutFile were successful.
    // We can visually verify by examining the LastErrorText that was recorded for each
    // of these method calls..
    int numTasks = taskChain.get_NumTasks();
    int taskIdx = 0;

    while ((taskIdx < numTasks)) {

        task = taskChain.GetTask(taskIdx);

        // Examine the status of this task, and the ResultErrorText
        // (the ResultErrorText is the ftp.LastErrorText captured for FTP method called by the task).
        // Everything should indicate success.
        System.out.println("task status: " + task.status());
        System.out.println("task log: " + task.resultErrorText());

        taskIdx = taskIdx+1;
        }

    success = ftp.Disconnect();
  }
}