Interface IProgressMonitor

  • All Known Subinterfaces:
    IProgressMonitorWithBlocking
    All Known Implementing Classes:
    NullProgressMonitor, ProgressMonitorPart, ProgressMonitorWrapper, SubMonitor, SubProgressMonitor

    public interface IProgressMonitor
    The IProgressMonitor interface 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 cancelation 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).

    CALLER/CALLEE RESPONSIBILITIES:

    Methods that receive an IProgressMonitor ("callees") must either obey the following conventions or include JavaDoc explaining how it differs from these rules. The called method:

    The caller:

    The responsibilities described above were introduced in Eclipse 4.7 (Oxygen). Prior to Eclipse 4.7, it was common practice for the callee to invoke done() on its monitor and for the caller to rely upon this fact. As of Eclipse 4.6, all the important top-level entry points have been updated to call done(), meaning they work with both methods that invoke done() and methods that don't.

    Since this convention was introduced in Eclipse 4.7, some plugin code may need to change. In particular, callers that pass a monitor are no longer allowed to rely upon the callee invoking done() and must do so themselves if necessary.

    This interface can be used without OSGi running.

    Clients may implement this interface.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static int UNKNOWN
      Constant indicating an unknown amount of work.
    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void beginTask​(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.
      void internalWorked​(double work)
      Internal method to handle scaling correctly.
      boolean isCanceled()
      Returns whether cancelation of current operation has been requested.
      void setCanceled​(boolean value)
      Sets the cancel state to the given value.
      void setTaskName​(String name)
      Sets the task name to the given value.
      void subTask​(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

        static final int UNKNOWN
        Constant indicating an unknown amount of work.
        See Also:
        Constant Field Values
    • Method Detail

      • beginTask

        void beginTask​(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).
      • internalWorked

        void internalWorked​(double work)
        Internal method to handle scaling correctly. This method must not be called by a client. Clients should always use the method worked(int).
        Parameters:
        work - the amount of work done
      • 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()
      • setTaskName

        void setTaskName​(String name)
        Sets the task name to the given value. This method is used to restore the task label after a nested operation was executed. Normally there is no need for clients to call this method.
        Parameters:
        name - the name (or description) of the main task
        See Also:
        beginTask(java.lang.String, int)
      • subTask

        void subTask​(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 - a non-negative number of work units just completed