Java双端队列toString方法覆盖左元素

import java.util.ArrayDeque;
import java.util.Deque;

public class MyDeque<E> extends ArrayDeque<E> {
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("MyDeque: [");
        for (E element : this) {
            sb.append(element.toString());
            sb.append(", ");
        }
        if (!isEmpty()) {
            sb.delete(sb.length() - 2, sb.length());
        }
        sb.append("]");
        return sb.toString();
    }

    public static void main(String[] args) {
        MyDeque<Integer> deque = new MyDeque<>();
        deque.addFirst(1);
        deque.addLast(2);
        deque.addLast(3);
        System.out.println(deque.toString()); // 输出：MyDeque: [1, 2, 3]
    }
}