深入淺析Java的數(shù)據(jù)結(jié)構(gòu)中的圖

 protected class Edge implements java.io.Serializable {
     private VertexInterface<T> vertex;// 終點(diǎn)
    private double weight;//權(quán)值

class Vertex<T> implements VertexInterface<T>, java.io.Serializable {
  private T label;//標(biāo)識(shí)標(biāo)點(diǎn),可以用不同類型來標(biāo)識(shí)頂點(diǎn)如String,Integer....
  private List<Edge> edgeList;//到該頂點(diǎn)鄰接點(diǎn)的邊,實(shí)際以java.util.LinkedList存儲(chǔ)
  private boolean visited;//標(biāo)識(shí)頂點(diǎn)是否已訪問
  private VertexInterface<T> previousVertex;//該頂點(diǎn)的前驅(qū)頂點(diǎn)
  private double cost;//頂點(diǎn)的權(quán)值,與邊的權(quán)值要區(qū)別開來

   public T getLabel() {
     return label;
   }

 public Iterator<VertexInterface<T>> getNeighborInterator() {
     return new NeighborIterator();
   }

/**Task: 遍歷該頂點(diǎn)鄰接點(diǎn)的迭代器--為 getNeighborInterator()方法 提供迭代器
   * 由于頂點(diǎn)的鄰接點(diǎn)以邊的形式存儲(chǔ)在java.util.List中,因此借助List的迭代器來實(shí)現(xiàn)
   * 由于頂點(diǎn)的鄰接點(diǎn)由Edge類封裝起來了--見Edge.java的定義的第一個(gè)屬性
   * 因此，首先獲得遍歷Edge對(duì)象的迭代器,再根據(jù)獲得的Edge對(duì)象解析出鄰接點(diǎn)對(duì)象
   */
  private class NeighborIterator implements Iterator<VertexInterface<T>>{
    Iterator<Edge> edgesIterator;
    private NeighborIterator() {
      edgesIterator = edgeList.iterator();//獲得遍歷edgesList 的迭代器
    }
    @Override
    public boolean hasNext() {
      return edgesIterator.hasNext();
    }
    @Override
    public VertexInterface<T> next() {
      VertexInterface<T> nextNeighbor = null;
      if(edgesIterator.hasNext()){
        Edge edgeToNextNeighbor = edgesIterator.next();//LinkedList中存儲(chǔ)的是Edge
        nextNeighbor = edgeToNextNeighbor.getEndVertex();//從Edge對(duì)象中取出頂點(diǎn)
      }
      else
        throw new NoSuchElementException();
      return nextNeighbor;
    }
    @Override
    public void remove() {
      throw new UnsupportedOperationException();
    }
  }

  public boolean isVisited() {
    return visited;
   }

   public boolean hasPredecessor() {//判斷頂點(diǎn)是否有前驅(qū)頂點(diǎn)
     return this.previousVertex != null;
   }
  public VertexInterface<T> getPredecessor() {//獲得前驅(qū)頂點(diǎn)
     return this.previousVertex;
  }

 public void setCost(double newCost) {
     cost = newCost;
   }
 public double getCost() {
    return cost;
  } 

package graph;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.NoSuchElementException;
class Vertex<T> implements VertexInterface<T>, java.io.Serializable {
  private T label;//標(biāo)識(shí)標(biāo)點(diǎn),可以用不同類型來標(biāo)識(shí)頂點(diǎn)如String,Integer....
  private List<Edge> edgeList;//到該頂點(diǎn)鄰接點(diǎn)的邊,實(shí)際以java.util.LinkedList存儲(chǔ)
  private boolean visited;//標(biāo)識(shí)頂點(diǎn)是否已訪問
  private VertexInterface<T> previousVertex;//該頂點(diǎn)的前驅(qū)頂點(diǎn)
  private double cost;//頂點(diǎn)的權(quán)值,與邊的權(quán)值要區(qū)別開來
  public Vertex(T vertexLabel){
    label = vertexLabel;
    edgeList = new LinkedList<Edge>();//是Vertex的屬性,說明每個(gè)頂點(diǎn)都有一個(gè)edgeList用來存儲(chǔ)所有與該頂點(diǎn)關(guān)系的邊
    visited = false;
    previousVertex = null;
    cost = 0;
  }
  /**
   *Task: 這里用了一個(gè)單獨(dú)的類來表示邊,主要是考慮到帶權(quán)值的邊
   *可以看出,Edge類封裝了一個(gè)頂點(diǎn)和一個(gè)double類型變量 
   *若不需要考慮權(quán)值,可以不需要單獨(dú)創(chuàng)建一個(gè)Edge類來表示邊,只需要一個(gè)保存頂點(diǎn)的列表即可
   * @author hapjin
   */
  protected class Edge implements java.io.Serializable {
    private VertexInterface<T> vertex;// 終點(diǎn)
    private double weight;//權(quán)值
    //Vertex 類本身就代表頂點(diǎn)對(duì)象,因此在這里只需提供 endVertex，就可以表示一條邊了
    protected Edge(VertexInterface<T> endVertex, double edgeWeight){
      vertex = endVertex;
      weight = edgeWeight;
    }
    protected VertexInterface<T> getEndVertex(){
      return vertex;
    }
    protected double getWeight(){
      return weight;
    }
  }
  /**Task: 遍歷該頂點(diǎn)鄰接點(diǎn)的迭代器--為 getNeighborInterator()方法 提供迭代器
   * 由于頂點(diǎn)的鄰接點(diǎn)以邊的形式存儲(chǔ)在java.util.List中,因此借助List的迭代器來實(shí)現(xiàn)
   * 由于頂點(diǎn)的鄰接點(diǎn)由Edge類封裝起來了--見Edge.java的定義的第一個(gè)屬性
   * 因此，首先獲得遍歷Edge對(duì)象的迭代器,再根據(jù)獲得的Edge對(duì)象解析出鄰接點(diǎn)對(duì)象
   */
  private class NeighborIterator implements Iterator<VertexInterface<T>>{
    Iterator<Edge> edgesIterator;
    private NeighborIterator() {
      edgesIterator = edgeList.iterator();//獲得遍歷edgesList 的迭代器
    }
    @Override
    public boolean hasNext() {
      return edgesIterator.hasNext();
    }
    @Override
    public VertexInterface<T> next() {
      VertexInterface<T> nextNeighbor = null;
      if(edgesIterator.hasNext()){
        Edge edgeToNextNeighbor = edgesIterator.next();//LinkedList中存儲(chǔ)的是Edge
        nextNeighbor = edgeToNextNeighbor.getEndVertex();//從Edge對(duì)象中取出頂點(diǎn)
      }
      else
        throw new NoSuchElementException();
      return nextNeighbor;
    }
    @Override
    public void remove() {
      throw new UnsupportedOperationException();
    }
  }
  /**Task: 生成一個(gè)遍歷該頂點(diǎn)所有鄰接邊的權(quán)值的迭代器
   * 權(quán)值是Edge類的屬性,因此先獲得一個(gè)遍歷Edge對(duì)象的迭代器,取得Edge對(duì)象,再獲得權(quán)值
   * @author hapjin
   *
   * @param <Double> 權(quán)值的類型
   */
  private class WeightIterator implements Iterator{//這里不知道為什么,用泛型報(bào)編譯錯(cuò)誤&#63;&#63;&#63;
    private Iterator<Edge> edgesIterator;
    private WeightIterator(){
      edgesIterator = edgeList.iterator();
    }
    @Override
    public boolean hasNext() {
      return edgesIterator.hasNext();
    }
    @Override
    public Object next() {
      Double result;
      if(edgesIterator.hasNext()){
        Edge edge = edgesIterator.next();
        result = edge.getWeight();
      }
      else throw new NoSuchElementException();
      return (Object)result;//從迭代器中取得結(jié)果時(shí),需要強(qiáng)制轉(zhuǎn)換成Double
    }
    @Override
    public void remove() {
      throw new UnsupportedOperationException();
    }
  }
  @Override
  public T getLabel() {
    return label;
  }
  @Override
  public void visit() {
    this.visited = true;
  }
  @Override
  public void unVisit() {
    this.visited = false;
  }
  @Override
  public boolean isVisited() {
    return visited;
  }
  @Override
  public boolean connect(VertexInterface<T> endVertex, double edgeWeight) {
    // 將"邊"(邊的實(shí)質(zhì)是頂點(diǎn))插入頂點(diǎn)的鄰接表
    boolean result = false;
    if(!this.equals(endVertex)){//頂點(diǎn)互不相同
      Iterator<VertexInterface<T>> neighbors = this.getNeighborInterator();
      boolean duplicateEdge = false;
      while(!duplicateEdge && neighbors.hasNext()){//保證不添加重復(fù)的邊
        VertexInterface<T> nextNeighbor = neighbors.next();
        if(endVertex.equals(nextNeighbor)){
          duplicateEdge = true;
          break;
        }
      }//end while
      if(!duplicateEdge){
        edgeList.add(new Edge(endVertex, edgeWeight));//添加一條新邊
        result = true;
      }//end if
    }//end if
    return result;
  }
  @Override
  public boolean connect(VertexInterface<T> endVertex) {
    return connect(endVertex, 0);
  }
  @Override
  public Iterator<VertexInterface<T>> getNeighborInterator() {
    return new NeighborIterator();
  }
  @Override
  public Iterator getWeightIterator() {
    return new WeightIterator();
  }
  @Override
  public boolean hasNeighbor() {
    return !(edgeList.isEmpty());//鄰接點(diǎn)實(shí)質(zhì)是存儲(chǔ)是List中
  }
  @Override
  public VertexInterface<T> getUnvisitedNeighbor() {
    VertexInterface<T> result = null;
    Iterator<VertexInterface<T>> neighbors = getNeighborInterator();
    while(neighbors.hasNext() && result == null){//獲得該頂點(diǎn)的第一個(gè)未被訪問的鄰接點(diǎn)
      VertexInterface<T> nextNeighbor = neighbors.next();
      if(!nextNeighbor.isVisited())
        result = nextNeighbor;
    }
    return result;
  }
  @Override
  public void setPredecessor(VertexInterface<T> predecessor) {
    this.previousVertex = predecessor;
  }
  @Override
  public VertexInterface<T> getPredecessor() {
    return this.previousVertex;
  }
  @Override
  public boolean hasPredecessor() {
    return this.previousVertex != null;
  }
  @Override
  public void setCost(double newCost) {
    cost = newCost;
  }
  @Override
  public double getCost() {
    return cost;
  }
  //判斷兩個(gè)頂點(diǎn)是否相同
  public boolean equals(Object other){
    boolean result;
    if((other == null) || (getClass() != other.getClass()))
      result = false;
    else
    {
      Vertex<T> otherVertex = (Vertex<T>)other;
      result = label.equals(otherVertex.label);//節(jié)點(diǎn)是否相同最終還是由標(biāo)識(shí) 節(jié)點(diǎn)類型的類的equals() 決定
    }
    return result;
  }
}