Class OperationHistoryActionHandler

  • All Implemented Interfaces:
    IAdaptable, IAction, ActionFactory.IWorkbenchAction
    Direct Known Subclasses:
    RedoActionHandler, UndoActionHandler

    public abstract class OperationHistoryActionHandler
    extends Action
    implements ActionFactory.IWorkbenchAction, IAdaptable

    OperationHistoryActionHandler implements common behavior for the undo and redo actions. It supports filtering of undo or redo on a particular undo context. If an undo context is not specified, or there has been no history available for the specified undo context, then the workbench undo context will be used.

    OperationHistoryActionHandler provides an adapter in the info parameter of the IOperationHistory undo and redo methods that is used to get UI info for prompting the user during operations or operation approval. Adapters are provided for org.eclipse.ui.IWorkbenchWindow, org.eclipse.swt.widgets.Shell, org.eclipse.ui.IWorkbenchPart, org.eclipse.core.commands.IUndoContext, and org.eclipse.runtime.IProgressMonitor.

    OperationHistoryActionHandler assumes a linear undo/redo model. When the handler is run, the operation history is asked to perform the most recent undo/redo for the handler's undo context. The handler can be configured (using #setPruneHistory(true)) to flush the operation undo or redo history for the handler's undo context when there is no valid operation on top of the history. This avoids keeping a stale history of invalid operations. By default, pruning does not occur and it is assumed that clients of the particular undo context are pruning the history when necessary.

    Since:
    3.1
    • Method Detail

      • run

        public final void run()
        Description copied from class: Action
        The default implementation of this IAction method does nothing. Subclasses should override this method if they do not need information from the triggering event, or override runWithEvent(Event) if they do.
        Specified by:
        run in interface IAction
        Overrides:
        run in class Action
        See Also:
        How radio buttons are handled, How check boxes are handled
      • getAdapter

        public <T> T getAdapter​(Class<T> adapter)
        Description copied from interface: IAdaptable
        Returns an object which is an instance of the given class associated with this object. Returns null if no such object can be found.

        Clients may implement this method but should generally call Adapters.adapt(Object, Class, boolean) rather than invoking it directly.

        Specified by:
        getAdapter in interface IAdaptable
        Type Parameters:
        T - the class type
        Parameters:
        adapter - the adapter class to look up
        Returns:
        a object of the given class, or null if this object does not have an adapter for the given class
      • setContext

        public void setContext​(IUndoContext context)
        Set the context shown by the handler. Normally the context is set up when the action handler is created, but the context can also be changed dynamically.
        Parameters:
        context - the context to be used for the undo history
      • setPruneHistory

        public void setPruneHistory​(boolean prune)
        Specify whether the action handler should actively prune the operation history when invalid operations are encountered. The default value is false.
        Parameters:
        prune - true if the history should be pruned by the handler, and false if it should not.
      • update

        public void update()
        Update enabling and labels according to the current status of the operation history.