设计模式-备忘录模式（三）

public class TextEditorHistory {
    private Stack<TextEditorMemento> mementos = new Stack<>();

    public void save(TextEditor editor) {
        mementos.push(editor.createMemento());
    }

    public void undo(TextEditor editor) {
        if (!mementos.isEmpty()) {
            TextEditorMemento memento = mementos.pop();
            editor.restoreMemento(memento);
        }
    }
}

public class Test {
    public static void main(String[] args) {
        TextEditor editor = new TextEditor("Hello, world!");
        TextEditorHistory history = new TextEditorHistory();

        // Save the initial state
        history.save(editor);

        // Modify the text and position
        editor.setText("Goodbye, world!");
        editor.setCursorPosition(7);

        // Save the new state
        history.save(editor);

        // Undo the last change
        history.undo(editor);

        // Check the current state
        System.out.println(editor.getText());           // Output: Hello, world!
        System.out.println(editor.getCursorPosition()); // Output: 0
    }
}