【学习笔记】Iterator迭代器

package collection;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

@SuppressWarnings("all")

//        hasNext: 判断是否有下一个元素
//        next: 指针后移并返回当前元素
//        remove: 删除指针当前指向的元素

public class CollectionIterator {
    public static void main(String[] args) {
        List col = new ArrayList();
        col.add(new Book("西游记","吴承恩",44.6));
        col.add(new Book("红楼梦","曹雪芹",38.9));
        col.add(new Book("水浒传","罗贯中",66.6));
        System.out.println(col);
        /* 遍历这个列表 */
        // 1. 先得到col对应的迭代器
        Iterator it = col.iterator();
        // 2. 使用while循环遍历即可，快捷键itit
        while(it.hasNext()){
            Object obj = it.next();    // 返回的是Object对象
            System.out.println(obj);
        }
        // 3. 当退出while循环后，这时迭代器it指向最后的元素
//        it.next();  //报错 NoSuchElementException
        // 4. 想再次遍历，需要重置迭代器
        it = col.iterator();
    }
}

class Book {
    String name;
    String author;
    double price;

    public Book(String name, String author, double price) {
        this.name = name;
        this.author = author;
        this.price = price;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                '}';
    }
}