Interface IProgressListener

  • All Known Implementing Classes:
    ConsoleProgressListener, ProgressMonitorWrapper, SilentProgressListener, SimpleMonitor.Listener, VoidProgressListener

    public interface IProgressListener
    This interface is closely modeled after { link org.eclipse.core.runtime.IProgressMonitor}. The latter has not been used to avoid a dependency. It is implemented by objects that monitor the progress of an activity; the methods in this interface are invoked by code that performs the activity.

    All activity is broken down into a linear sequence of tasks against which progress is reported. When a task begins, a beginTask(String, int) notification is reported, followed by any number and mixture of progress reports (worked() ) and subtask notifications (subTask(String)). When the task is eventually completed, a done() notification is reported. After the done() notification, the progress monitor cannot be reused; i.e., beginTask(String, int) cannot be called again after the call to done().

    A request to cancel an operation can be signaled using the setCanceled method. Operations taking a progress monitor are expected to poll the monitor (using isCanceled) periodically and abort at their earliest convenience. Operation can however choose to ignore cancellation requests.

    Since notification is synchronous with the activity itself, the listener should provide a fast and robust implementation. If the handling of notifications would involve blocking operations, or operations which might throw uncaught exceptions, the notifications should be queued, and the actual processing deferred (or perhaps delegated to a separate thread).

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Interface Description
      static class  IProgressListener.OperationCanceledException
      Helper exception class which can be used to exit an operation via an exception if the operation itself has been canceled.
      static class  IProgressListener.Severity
      Defines the severities possible for a user message.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static int UNKNOWN_TOTAL_WORK
      Constant which may be used to indicate that the total amount of work units is not known.
    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void beginTask​(java.lang.String name, int totalWork)
      Notifies that the main task is beginning.
      void done()
      Notifies that the work is done; that is, either the main task is completed or the user canceled it.
      boolean isCanceled()
      Returns whether cancelation of current operation has been requested.
      void sendUserMessage​(IProgressListener.Severity severity, java.lang.String message, java.lang.Throwable exception)
      Sends a message to the user.
      void setCanceled​(boolean value)
      Sets the cancel state to the given value.
      void subTask​(java.lang.String name)
      Notifies that a subtask of the main task is beginning.
      void worked​(int work)
      Notifies that a given number of work unit of the main task has been completed.
    • Field Detail

      • UNKNOWN_TOTAL_WORK

        static final int UNKNOWN_TOTAL_WORK
        Constant which may be used to indicate that the total amount of work units is not known.
        See Also:
        Constant Field Values
    • Method Detail

      • beginTask

        void beginTask​(java.lang.String name,
                       int totalWork)
        Notifies that the main task is beginning. This must only be called once on a given progress monitor instance.
        Parameters:
        name - the name (or description) of the main task
        totalWork - the total number of work units into which the main task is been subdivided. If the value is UNKNOWN the implementation is free to indicate progress in a way which doesn't require the total number of work units in advance.
      • done

        void done()
        Notifies that the work is done; that is, either the main task is completed or the user canceled it. This method may be called more than once (implementations should be prepared to handle this case).
      • isCanceled

        boolean isCanceled()
        Returns whether cancelation of current operation has been requested. Long-running operations should poll to see if cancelation has been requested.
        Returns:
        true if cancellation has been requested, and false otherwise
        See Also:
        setCanceled(boolean)
      • setCanceled

        void setCanceled​(boolean value)
        Sets the cancel state to the given value.
        Parameters:
        value - true indicates that cancelation has been requested (but not necessarily acknowledged); false clears this flag
        See Also:
        isCanceled()
      • subTask

        void subTask​(java.lang.String name)
        Notifies that a subtask of the main task is beginning. Subtasks are optional; the main task might not have subtasks.
        Parameters:
        name - the name (or description) of the subtask
      • worked

        void worked​(int work)
        Notifies that a given number of work unit of the main task has been completed. Note that this amount represents an installment, as opposed to a cumulative amount of work done to date.
        Parameters:
        work - the number of work units just completed
      • sendUserMessage

        void sendUserMessage​(IProgressListener.Severity severity,
                             java.lang.String message,
                             java.lang.Throwable exception)
        Sends a message to the user.
        Parameters:
        severity - Severity as defined in IProgressListener.Severity
        message - The message localized to the current locale.
        exception - The relevant low-level exception, or null if none.