Memento在Java中不使用撤消更新状态

我有一个包含顶点和边的图，还有一个originator类，它包含了应该用来插入顶点或获取图中顶点列表的图

界面顶点

使用插入新顶点的接口图，其他方法是隐藏

public interface Graph<V, E> {
  public void insertVertex(V vElement);
  public Iterable<Vertex<V>> vertices();
}

班级纪念品

班级发起人

类管理员实现接口IMemento

但当我恢复de图时，仍然有两个顶点

caretaker.restore(originator);

---

有什么建议吗？

您正在引用纪念品中的相同顶点集合

尝试更改以下类：

public class Originator<V,E> {
    private Graph<V,E> graph;
    private Caretaker caretaker;

    public Originator(Caretaker caretaker) {
      this.graph = new GraphEdgeList();
      this.caretaker = caretaker;
    }

    public Originator(Originator<V, E> originator) {
         this.graph = new GraphEdgeList((GraphEdgeList) originator.getGraph());
         this.caretaker = originator.getCaretaker();
    }

    public Memento createMemento() {//create new memento
        return new Memento(new Originator(this));
    }

    public void setMemento(Memento memento) {//set memento
       graph = memento.getGraph();
    }

    public Graph getGraph() {
      return graph;
    }

    public Caretaker getCaretaker() {
     return caretaker;
    }
}

请参阅新的构造函数

public class GraphEdgeList<V, E> implements Graph<V, E> {
    private Map<V, Vertex<V>> vertices;

    public GraphEdgeList() {
        this.vertices = new HashMap<>();
    }

    public GraphEdgeList(GraphEdgeList graph) {
         this.vertices = new HashMap<>();
         this.vertices.putAll(graph.getVertices());
    }

    @Override
    public void insertVertex(V vElement) {
        this.vertices.put(vElement, null);
    }

    public Map<V, Vertex<V>> getVertices() {
        return vertices;
    }

    public void setVertices(Map<V, Vertex<V>> vertices) {
        this.vertices = vertices;
    }

    @Override
    public Iterable<Vertex<V>> vertices() {
        return this.vertices.values();
    }

    @Override
    public String toString() {
        return "GraphEdgeList [vertices=" + vertices + "]";
    } 
}

---

因为不更新图形，所以只更新堆栈，所以它不会在originator.getGraph中反映它method@dkb，当我创建memento公共MementoOriginator发起人{graph=originator.getGraph；}memento图是receive the graph of originator，当我还原memento public void SetMementomento 2 memento{this.graph=memento.getGraph；}时，originator图是receive the memento图，也就是说，它的作用相反，尽管我不知道这是否是最好的解决方案

public class Memento {
    private Graph graph;

    public Memento(Originator originator) {
        graph = originator.getGraph();
    }

    public Graph getGraph() {
        return graph;
    }
}

public class Originator<V,E> {
    private Graph<V,E> graph;
    private Caretaker caretaker;

    public Originator(Caretaker caretaker) {
      this.graph = new GraphEdgeList();
      this.caretaker = caretaker;
    }

    public Memento createMemento() {//create new memento
        return new Memento(this);
    }

    public void setMemento(Memento memento) {//set memento
       graph = memento.getGraph();
    }

    public Graph getGraph() {
      return graph;
    }

    public Caretaker getCaretaker() {
     return caretaker;
    }
}

public interface IMemento {
    public void save(Originator originator);
    public void restore(Originator originator);
}

public class Caretaker implements IMemento {

    private final Stack<Memento> undoMemento;//stack explicit

    public Caretaker() {
        this.undoMemento = new StackDynamic();
    }

    @Override
    public void save(Originator originator) {
        Memento memento = originator.createMemento();
        undoMemento.push(memento);
    }

    @Override
    public void restore(Originator originator) {
        if (undoMemento.isEmpty() != true) {
            Memento memento = undoMemento.pop();
            originator.setMemento(memento);
       }
    }
}

public class Main {
    public static void main(String[] args) {
        Caretaker caretaker = new Caretaker();
        Originator<String, String> originator = new Originator(caretaker);

        //create new string and insert in graph
        originator.getGraph.insertVertex("A");
        //caretaker save state
        caretaker.save(originator);

       //create another string and insert in graph
        originator.getGraph.insertVertex("B");
        //caretaker save state
        caretaker.save(originator);      
    }
}

caretaker.restore(originator);

public class Originator<V,E> {
    private Graph<V,E> graph;
    private Caretaker caretaker;

    public Originator(Caretaker caretaker) {
      this.graph = new GraphEdgeList();
      this.caretaker = caretaker;
    }

    public Originator(Originator<V, E> originator) {
         this.graph = new GraphEdgeList((GraphEdgeList) originator.getGraph());
         this.caretaker = originator.getCaretaker();
    }

    public Memento createMemento() {//create new memento
        return new Memento(new Originator(this));
    }

    public void setMemento(Memento memento) {//set memento
       graph = memento.getGraph();
    }

    public Graph getGraph() {
      return graph;
    }

    public Caretaker getCaretaker() {
     return caretaker;
    }
}

public class GraphEdgeList<V, E> implements Graph<V, E> {
    private Map<V, Vertex<V>> vertices;

    public GraphEdgeList() {
        this.vertices = new HashMap<>();
    }

    public GraphEdgeList(GraphEdgeList graph) {
         this.vertices = new HashMap<>();
         this.vertices.putAll(graph.getVertices());
    }

    @Override
    public void insertVertex(V vElement) {
        this.vertices.put(vElement, null);
    }

    public Map<V, Vertex<V>> getVertices() {
        return vertices;
    }

    public void setVertices(Map<V, Vertex<V>> vertices) {
        this.vertices = vertices;
    }

    @Override
    public Iterable<Vertex<V>> vertices() {
        return this.vertices.values();
    }

    @Override
    public String toString() {
        return "GraphEdgeList [vertices=" + vertices + "]";
    } 
}