Package jebl.util

Class ProgressListener

java.lang.Object
jebl.util.ProgressListener
All Implemented Interfaces:
Cancelable
Direct Known Subclasses:
BasicProgressListener, CompositeProgressListener, ProgressListener.Wrapper

public abstract class ProgressListener extends Object implements Cancelable
Version:
$Id: ProgressListener.java 1068 2010-09-08 23:59:59Z matt_kearse $ ProgressListener guarantees the following contract: A call to any of the methods setProgress(), setMessage(), isCanceled() and setIndeterminateProgress() at a given time yields the same result as a call to another of these methods would have resulted at the same time. Once the task whose progress we are observing has been canceled, calls to either of these methods reflect this. This does not prevent subclasses from introducing a way to "reset" a ProgressListener that was previously canceled from not being canceled any more. Any object may exhibit undefined behaviour when dealing with a ProgressListener that is not fulfilling this contract.
Author:
Matt Kearse
  • Field Details

    • EMPTY

      public static final ProgressListener EMPTY
      A ProgressListener that ignores all events and always returns false from isCanceled(). Useful when you don't care about the progress results or canceling the operation.
  • Constructor Details

    • ProgressListener

      public ProgressListener()
  • Method Details

    • setProgress

      public final boolean setProgress(double fractionCompleted)
      Parameters:
      fractionCompleted - a number between 0 and 1 inclusive representing the fraction of the operation completed. If you are unsure of the fraction completed, call setIndeterminateProgress() instead.
      Returns:
      true if the user has requested that this operation be canceled.
    • setProgress

      public final boolean setProgress(int currentStep, int numberOfSteps)
      Parameters:
      currentStep - between 0 and numberOfSteps inclusive
      numberOfSteps - the total number of steps. Must be greater than 0.
      Returns:
      true if the user has requested that this operation be canceled.
    • setProgress

      public final boolean setProgress(long currentStep, long numberOfSteps)
      Parameters:
      currentStep - between 0 and numberOfSteps inclusive
      numberOfSteps - the total number of steps. Must be greater than 0.
      Returns:
      true if the user has requested that this operation be canceled.
    • setIndeterminateProgress

      public final boolean setIndeterminateProgress()
      Sets indefinite progress (i.e. "some progress has happened, but I don't know how close we are to finishing").
      Returns:
      true if the user has requested that this operation be canceled.
    • setMessage

      public final boolean setMessage(String message)
      Set visible user message.
      Parameters:
      message - a user visible message. If this is null, it will be automatically replaced with an empty string.
      Returns:
      true if the user has requested that this operation be canceled.
    • setImage

      public final boolean setImage(Image image)
      Set an image associated with the current progress. A progress listener may choose to optionally display this image wherever is appropriate.
      Parameters:
      image - an image
      Returns:
      true if the user has requested that this operation be canceled.
    • addFeedbackAction

      public void addFeedbackAction(String label, SimpleListener listener)
    • addFeedbackAction

      public void addFeedbackAction(String label, String description, SimpleListener listener)
      Adds an action that can choose to provide feedback. For example, an operation may choose to provide a "Skip to next step" button alongside the cancel button. There is no requirement that a ProgressListener actually present this to the user - it may choose to ignore this method, in which case listener will never be fired.
      Parameters:
      label - a label describing this feedback action. For example, "Skip to next step"
      listener - a listener to be notified when the user chooses to invoke this action
    • removeFeedbackAction

      public void removeFeedbackAction(String label)
      Removes a feedback action previously added using addFeedbackAction(String, jebl.util.SimpleListener).
      Parameters:
      label - The label used as a parameter to addFeedbackAction(String, jebl.util.SimpleListener)
    • setTitle

      public void setTitle(String title)
      Sets a title associated with whatever is being done. This will not necessarily even be presented to the user, but typically will be presented as the title of a progress window.
      Parameters:
      title - the title of a progress window (if any). Must not be null.
    • isCanceled

      public abstract boolean isCanceled()
      This method must be implemented by all subclasses. It is called from setProgress(double), setIndeterminateProgress() and setMessage(java.lang.String) to determine the return value of these methods.
      Specified by:
      isCanceled in interface Cancelable
      Returns:
      true if the user has requested that this operation be canceled.