php设计模式 Interator (迭代器模式)

<?php
/**
 * 迭代器模式
 *
 * 提供一个方法顺序访问一聚合对象中的各个元素,而又不暴露对象的内部表示
 */
interface Interator {
    public function next();
    public function first();
    public function current();
    public function isDone();
}
class SomeInterator implements Interator {
    private $_arr = array();
    public function __construct($arr) {
        $this->_arr = $arr;
    }
    public function first() {
        return $this->_arr[0];
    }
    public functioncurrent() {
        return current($this->_arr);
    }
    public functionnext() {
        return next($this->_arr);
    }
    public function isDone() {
    }
}
$objSomeInterator=new SomeInterator(array(1,2,3,4,6,7));
echo $objSomeInterator->first() , "<br/>";
echo $objSomeInterator->next() , "<br/>";
echo $objSomeInterator->current() , "<br/>";
echo $objSomeInterator->current() , "<br/>";
echo $objSomeInterator->next() , "<br/>";
echo $objSomeInterator->current() , "<br/>";