PHP基础之预定义接口2——Iterator接口

这个例子展示了使用 foreach 时，迭代器方法的调用顺序。

<?php
    class myIterator implements Iterator {
        private $position = 0;
        private $array = array(
            "firstelement",
            "secondelement",
            "lastelement",
        );

        public function __construct() {
            $this->position = 0;
        }

        function rewind() {
            var_dump(__METHOD__);
            $this->position = 0;
        }

        function current() {
            var_dump(__METHOD__);
            return $this->array[$this->position];
        }

        function key() {
            var_dump(__METHOD__);
            return $this->position;
        }

        function next() {
            var_dump(__METHOD__);
            ++$this->position;
        }

        function valid() {
            var_dump(__METHOD__);
            return isset($this->array[$this->position]);
        }
    }

    $it = new myIterator;

    foreach($it as $key => $value) {
        var_dump($key, $value);
        echo "\n";
    }
?>

以上例程的输出类似于：