第10章 泛型

1、

class Operate<T> {
    private T[] arr = null;
    
    
    Operate(T[] arr) {
        this.arr = arr;
    }


    public T[] getArr() {
        return arr;
    }


    public void setArr(T[] arr) {
        this.arr = arr;
    }
    /*
     * 获取数组长度
     */
    public int size() {
        if(arr == null || arr.length == 0) {
            throw new RuntimeException("数组为空或者数组长度为0");
        }
        return arr.length;
    }
    /*
     * 获取指定位置的值
     */
    public T getValue(int index) {
        if(arr == null || index < 0 || arr.length == 0) {
            throw new RuntimeException("数组为空，或数组长度为0，或索引小于0");
        }
        return arr[index];
    }
    
}
public class OperateDemo {

    public static void main(String[] args) {
        String[] str = {"abc", "zaq", "xsw", "cde"};
        Integer[] in = {1, 2, 3, 4, 5};
        
        Operate<String> o1 = new Operate<String>(str);
        Operate<Integer> o2 = new Operate<Integer>(in);
        
        System.out.println(o1.getValue(2));
        System.out.println(o2.getValue(1));
        
        print(o1.getArr());
        print(o2.getArr());
    }

    public static <T> void print(T[] t) {
        for(int i = 0; i < t.length; i++) {
            System.out.println(t[i]);
        }
    }

}