我有一个包含graph
和vertices
一个edges
,我有一个包含应该用来originator
或graph
在insert vertices
的get the list of vertices
的graph
类
接口vertex
public interface Vertex<V> {
public V element();
}
接口edge
public interface Edge<E, V> {
public E element();
public Vertex<V>[] vertices();
}
用插入一个新的顶点和其他方法接口graph
是隐藏()
public interface Graph<V, E> {
public void insertVertex(V vElement);
public Iterable<Vertex<V>> vertices();
}
ADT Graph
实现存储vertices
的集合(和边缘,而不是需要)
public class GraphEdgeList<V, E> implements Graph<V, E> {
private Map<V, Vertex<V>> vertices;
public GraphEdgeList() {
this.vertices = new HashMap<>();
}
@Override
public void insertVertex(V vElement) {
//method to insert new vertex element
//not need to return nothing
}
@Override
public Iterable<Vertex<V>> vertices() {
//return a list of vertices in graph
}
}
类Memento
public class Memento {
private Graph graph;
public Memento(Originator originator) {
graph = originator.getGraph();
}
public Graph getGraph() {
return graph;
}
}
类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 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;
}
}
接口IMemento
public interface IMemento {
public void save(Originator originator);
public void restore(Originator originator);
}
类CareTaker
实现接口IMemento
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);
}
}
}
我怀疑节电状态,并尝试做撤消graph
不会更新到以前的状态时开始后,
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);
}
}
但是当我仍与2个顶点恢复德graph
caretaker.restore(originator);
什么建议吗?
你引用的备忘录内顶点的相同集合。
尝试改变如下类别:
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;
}
}
看到新的构造函数。
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 + "]";
}
}