java动态扩缩对象列表

有个列表，需要通过队尾的下标，动态缩减或者扩容，直接上代码：

 public static void main(String[] args) {
        List<String> initList = Arrays.asList("a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8", "a9", "a10");
        System.out.println("最终集合："+dynamicShapeList(initList, 5));
        System.out.println("最终集合："+dynamicShapeList(initList, 20));
    }

    /**
     * @Description: 动态扩缩对象列表
     * @Param: [input, endIndex]
     * @return: java.util.List<java.lang.String>
     * @Author: tom
     * @Date: 2023
     */
    private static List<String> dynamicShapeList(List<String> input, int endIndex) {
        List<String> output = new ArrayList<>();
        //结尾小于 就执行删除
        if (endIndex < input.size()) {
            List<String> delList = input.subList(endIndex, input.size());
            List<String> restList = input.subList(0, endIndex);
            //执行删除
            for (int i = 0; i < delList.size(); i++) {
                System.out.println("执行删除业务：" + delList.get(i));
            }
            output.addAll(restList);
        } else {
            output.addAll(input);
            //结尾大于等于 就增加
            Integer maxIndex = input.size();
            // 终止索引在已知数组结尾后
            for (int i = input.size(); i < endIndex; i++) {
                ++maxIndex;
                output.add("a" + maxIndex);
                System.out.println("执行保存业务：" + "a" + maxIndex);
            }
        }
        return output;
    }