/**
* A newer TextStorage is loaded using a memento object.
*/
public void Redo()
{
SnapShot backup = RedoStack.PopFromStack();
if (backup != null)
{
textStorage.RestoreStorage(backup.text);
}
}
/**
* If there exists a backup, it will be used to obtain
* newer text written by the user.
*/
public void Redo()
{
if (!RedoStack.IsEmpty())
{
if (backup != null)
{
backup.Redo();
}
}
else
{
Console.WriteLine("There is nothing to redo...\n");
}
}
/**
* An older TextStorage is loaded using a memento object.
* Allows Redo functionality by saving this SnapShot
* to another stack.
* Makes sure that text is empty if a backup doesn't exist.
*/
public void Undo()
{
if (UndoStack.PeekAtStack() != null)
{
RedoStack.PushToStack(UndoStack.PeekAtStack());
}
SnapShot backup = UndoStack.PopFromStack();
if (backup == null)
{
textStorage.RestoreStorage("");
}
else
{
textStorage.RestoreStorage(backup.text);
}
}