/// <summary>
/// Restores the subject to the next state on the redo stack, and stores the state before redoing to undo stack.
/// Method <see cref="CanRedo()"/> can be called before calling this method.
/// </summary>
/// <seealso cref="Undo()"/>
public void Redo()
{
if (tempMemento != null)
{
throw new InvalidOperationException("The complex memento wasn't commited.");
}
inUndoRedo = true;
IMemento <T> top = redoStack.Pop();
undoStack.Push(top.Restore(ref subject));
inUndoRedo = false;
}
