java - 从文件读取然后创建私有(private)类的对象

Question

我在公共(public)类 singleLinkedList 中有私有(private)类节点，并且我想从另一个公共(public)类移动列表(作为临时)，那么我如何创建临时节点或(方法)来移动列表。我无法将类 Node 更改为公共(public)，我应该保持私有(private)。编程的思想是:在 TextAnalyzer 类中从文件中读取数据，然后将其插入到 SinglyLinkedList 中并计算单词的频率。单链表类

   public class SinglyLinkedList<T> {
   private static class Node<T> {
   public T data;
    Node<T> next;
    public Node(T data) {
        this.data = data;
        next = null;
    }
}
Node<T> head;
Node<T> tail;
int size;

public SinglyLinkedList() {
    head = null;
    tail = null;
    size = 0;
}

public void insert(T S) {
    Node<T> temp = new Node<T>(S);
    if (head == null) {
        head = tail = temp;
        size++;
        return;
    }

    temp.next = head;
    head = temp;
    size++;
    return;
}

public void display() {
    Node<T> tmp = head;
    while (tmp != null) {
        System.out.println(tmp.data.toString());
        tmp = tmp.next;

    }

TextAnalyzer 类

  SinglyLinkedList<WData> list = new SinglyLinkedList<WData>();
   private static class WData {

    String word;
    int freq;

    public WData(String w, int f) {
        word = w;
        freq = f;
    }

    // .. Add other methods here as needed
    @Override
    public String toString() {
        // if(list.)
        return "WData{" + "word=" + word + " , freq=" + freq + '}';
    }
}
  public Scanner sc;

public void processText(String filename) {

    try {
        sc = new Scanner(new File(filename));
        while (sc.hasNext()) {
            String line = sc.next();
            String[] st = line.split(" ");

            for (int i = 0; i < st.length; i++) {

                processWord(st[i]);
        }}
    list.display();
       } catch (FileNotFoundException ex) {
        System.out.println("error in loadstudends Scanner");
    }
}
 public void processWord(String word) {
         Node<WData> temp = list.head;

    while (temp != null) {
        if (temp.data.word.equalsIgnoreCase(word)) {
            break;
        }
        temp = temp.next;
    }
    if (temp == null || Dtemp.data.word.matches(".*\\d.*")) {

        list.insert(new WData(word, 1));

    } else {
        temp.data.freq += 1;
    }
    }}

我们无法创建节点 temp，因为类节点是私有(private)的，所以我无法进行循环

Answer 1

您可能想要执行以下操作1. 在 SinglyLinkedList 中创建您自己的 Iterator 实现

public class MyIterator implements Iterator<T> {
    private Node<T> next = head;
    private Node<T> current = null;
    @Override
    public boolean hasNext() {
      return next != null;
    }
    @Override
    public T next() {
      if (hasNext()) {
        current = next;
        next = current.next;
        return current.data;
      }
      throw new NoSuchElementException();
    }

    @Override
    public void remove() {
      //TODO
    }
  }

制作SinglyLinkedList来实现Iterable

public class SinglyLinkedList<T> implements Iterable<T> {

调用 iterator() 时返回在 1 中创建的迭代器实例

  @Override
  public Iterator<T> iterator() {
    return new MyIterator();
  }

用于文本分析器类中的每个循环