php封装的有关问题

php封装的问题
[code=PHP][/code]
定义了一个User类
class User{

private $arr;//进行封装不让外部使用

function __construct(){
$this->arr = $this->get_data();//构造函数，在类一实例化的时候就会执行
}

public function isNotExist(){
echo "Does not exist
";
echo "重新输入";
}

private function get_data(){
$arr=array(
array("name"=>"张三","age"=>12,"sex"=>"男"),
array("name"=>"李四","age"=>25,"sex"=>"男"),
array("name"=>"王五","age"=>18,"sex"=>"男"),
array("name"=>"李利","age"=>16,"sex"=>"女"),
array("name"=>"陈明","age"=>25,"sex"=>"男"),
array("name"=>"张晓","age"=>25,"sex"=>"女"),
array("name"=>"李明","age"=>15,"sex"=>"男"),
array("name"=>"赵亮","age"=>25,"sex"=>"男"),
array("name"=>"张月","age"=>22,"sex"=>"男"),
array("name"=>"王青","age"=>21,"sex"=>"女")
);
return $arr;
}


public function joinHtml($array){
if(count($array)==0){
User::isNotExist();
}
$d = 0;
$b ="";
foreach($array as $t){
$d = $d+1;
$a = "




";
$b = $b.$a;
}
$b = $b . "

".$d."

".$t['name']."

".$t['age']."

".$t['sex']."

";
return $b;

}
//下面是继承User这个类，上面的不允许改变。
class newUser extends User{



function get_both_sex_ages($sex, $age1,$age2){


}
我需要在上面那个方法中调用$arr，不知道该怎么办，求解




------解决方案--------------------
基类Private派生类无法访问，这是面向对象的通用规则，要么基类直接提供访问private属性的public/protected接口给派生类使用，要么将属性直接设置为protected以便派生类的接口直接访问。