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

public class GenericDemo {
    public static void main(String[] args) {
        // 测试 Box 泛型类
        System.out.println("===== 测试 Box 泛型类 =====");
        Box<String> stringBox = new Box<>("Hello, Generics!");
        System.out.println(stringBox);
        
        Box<Integer> integerBox = new Box<>(100);
        System.out.println(integerBox);
        
        integerBox.setContent(200);
        System.out.println("修改后：" + integerBox);
        
        Box<Double> doubleBox = new Box<>();
        System.out.println("空盒子：" + doubleBox);
        System.out.println("是否为空：" + doubleBox.isEmpty());
        
        // 测试 Pair 泛型类
        System.out.println("\n===== 测试 Pair 泛型类 =====");
        Pair<String, Integer> nameAgePair = new Pair<>("张三", 25);
        System.out.println(nameAgePair);
        System.out.println("姓名：" + nameAgePair.getKey());
        System.out.println("年龄：" + nameAgePair.getValue());
        
        Pair<String, String> countryCapitalPair = new Pair<>("中国", "北京");
        System.out.println(countryCapitalPair);
        
        // 测试泛型方法
        System.out.println("\n===== 测试泛型方法 =====");
        String[] strArray = {"Java", "Python", "C++", "JavaScript"};
        System.out.print("字符串数组：");
        GenericUtils.printArray(strArray);
        
        Integer[] intArray = {1, 2, 3, 4, 5};
        System.out.print("原始数组：");
        GenericUtils.printArray(intArray);
        
        GenericUtils.swap(intArray, 0, 4);
        System.out.print("交换后数组：");
        GenericUtils.printArray(intArray);
        
        List<Double> doubleList = new ArrayList<>();
        doubleList.add(1.5);
        doubleList.add(2.5);
        doubleList.add(3.5);
        System.out.println("列表元素数量：" + GenericUtils.countListElements(doubleList));
    }
}