Class NonLocalUndoUserApprover

  • All Implemented Interfaces:
    IOperationApprover

    public final class NonLocalUndoUserApprover
    extends Object
    implements IOperationApprover

    An operation approver that prompts the user to see if a non-local undo should proceed inside an editor. A non-local undo is detected when an operation being undone or redone affects elements other than those described by the editor itself. Clients can optionally specify a class, the preferred comparison class, that should be used when comparing objects affected by the editor with objects affected by an undo or redo operation. Comparisons between the affected objects inside the editor and those described by the operation will first be done by simply performing an equality check, using Object.equals(java.lang.Object). If an object described by an operation is not equal to one of the objects affected by the editor, and if it is not an instance of the preferred comparison class, but is an instance of IAdaptable, then the operation approver will also attempt to retrieve an adapter on that object for the preferred comparison class and perform a second equality check using the adapter.

    This class may be instantiated by clients.

    Since:
    3.1
    • Constructor Detail

      • NonLocalUndoUserApprover

        public NonLocalUndoUserApprover​(IUndoContext context,
                                        IEditorPart part,
                                        Object[] affectedObjects,
                                        Class preferredComparisonClass)
        Create a NonLocalUndoUserApprover associated with the specified editor and undo context
        Parameters:
        context - the undo context of operations in question.
        part - the editor part that is displaying the element
        affectedObjects - the objects that are affected by the editor and considered to be objects local to the editor. The objects are typically instances of the preferredComparisonClass or else provide adapters for the preferredComparisonClass, although this is not required.
        preferredComparisonClass - the preferred class to be used when comparing the editor's affectedObjects with those provided by the undoable operation using IAdvancedUndoableOperation.getAffectedObjects(). If the operation's affected objects are not instances of the specified class, but are instances of IAdaptable, then an adapter for this class will be requested. The preferredComparisonClass may be null, which indicates that there is no expected class or adapter necessary for the comparison.
    • Method Detail

      • proceedRedoing

        public IStatus proceedRedoing​(IUndoableOperation operation,
                                      IOperationHistory history,
                                      IAdaptable uiInfo)
        Description copied from interface: IOperationApprover
        Return a status indicating whether the specified operation should be redone. Any status that does not have severity IStatus.OK will not be approved. Implementers should not assume that the redo will be performed when the status is OK, since other operation approvers may veto the redo.
        Specified by:
        proceedRedoing in interface IOperationApprover
        Parameters:
        operation - the operation to be redone
        history - the history redoing the operation
        uiInfo - the IAdaptable (or null) provided by the caller in order to supply UI information for prompting the user if necessary. When this parameter is not null, it should minimally contain an adapter for the org.eclipse.swt.widgets.Shell.class. Even if UI information is provided, the implementation of this method must be prepared for being called from a background thread. Any UI access must be properly synchronized using the techniques specified by the client's widget library.
        Returns:
        the IStatus describing whether the operation is approved. The redo will not proceed if the status severity is not OK, and the caller requesting the redo will be returned the status that caused the rejection. Any other status severities will not be interpreted by the history.
      • proceedUndoing

        public IStatus proceedUndoing​(IUndoableOperation operation,
                                      IOperationHistory history,
                                      IAdaptable uiInfo)
        Description copied from interface: IOperationApprover
        Return a status indicating whether the specified operation should be undone. Any status that does not have severity IStatus.OK will not be approved. Implementers should not assume that the undo will be performed when the status is OK, since other operation approvers can veto the undo.
        Specified by:
        proceedUndoing in interface IOperationApprover
        Parameters:
        operation - the operation to be undone
        history - the history undoing the operation
        uiInfo - the IAdaptable (or null) provided by the caller in order to supply UI information for prompting the user if necessary. When this parameter is not null, it should minimally contain an adapter for the org.eclipse.swt.widgets.Shell.class. Even if UI information is provided, the implementation of this method must be prepared for being called from a background thread. Any UI access must be properly synchronized using the techniques specified by the client's widget library.
        Returns:
        the IStatus describing whether the operation is approved. The undo will not proceed if the status severity is not OK, and the caller requesting the undo will be returned the status that caused the rejection. Any other status severities will not be interpreted by the history.