/**
* IteratorAggregate 源码
* Interface to create an external Iterator.
* @link https://php.net/manual/en/class.iteratoraggregate.php
*/
interface IteratorAggregate extends Traversable {
/**
* Retrieve an external iterator
* @link https://php.net/manual/en/iteratoraggregate.getiterator.php
* @return Traversable An instance of an object implementing <b>Iterator</b> or
* <b>Traversable</b>
* @since 5.0.0
*/
public function getIterator();
}
/**
* Iterator源码
* Interface for external iterators or objects that can be iterated
* themselves internally.
* @link https://php.net/manual/en/class.iterator.php
*/
interface Iterator extends Traversable {
/**
* Return the current element
* @link https://php.net/manual/en/iterator.current.php
* @return mixed Can return any type.
* @since 5.0.0
*/
public function current();
/**
* Move forward to next element
* @link https://php.net/manual/en/iterator.next.php
* @return void Any returned value is ignored.
* @since 5.0.0
*/
public function next();
/**
* Return the key of the current element
* @link https://php.net/manual/en/iterator.key.php
* @return mixed scalar on success, or null on failure.
* @since 5.0.0
*/
public function key();
/**
* Checks if current position is valid
* @link https://php.net/manual/en/iterator.valid.php
* @return boolean The return value will be casted to boolean and then evaluated.
* Returns true on success or false on failure.
* @since 5.0.0
*/
public function valid();
/**
* Rewind the Iterator to the first element
* @link https://php.net/manual/en/iterator.rewind.php
* @return void Any returned value is ignored.
* @since 5.0.0
*/
public function rewind();
}
/**
* 具体聚集类
* Class ConcreteAggregate
*/
class ConcreteAggregate implements \IteratorAggregate
{
private $data = [];
/**
* 往迭代器里面添加数据
*/
public function add($name)
{
$this->data[] = $name;
}
/**
* 获取迭代器
* @return ConcreteIterator|\Traversable
*/
public function getIterator()
{
// TODO: Implement getIterator() method.
return new ConcreteIterator($this->data);
}
}
/**
* 具体迭代器类
* Class ConcreteIterator
*/
class ConcreteIterator implements \Iterator
{
private $key = 0;
private $data = [];
public function __construct($data)
{
$this->data = $data;
$this->key = 0;
}
/**
* 返回当前元素
*/
public function current()
{
// TODO: Implement current() method.
return $this->data[$this->key];
}
/**
* 前进到下一个元素
*/
public function next()
{
// TODO: Implement next() method.
return $this->key++;
}
/**
* 返回当前元素的键
*/
public function key()
{
// TODO: Implement key() method.
return $this->key;
}
/**
* 检查当前位置是否有效
*/
public function valid()
{
// TODO: Implement valid() method.
return isset($this->data[$this->key]);
}
/**
* 将Iterator倒退到第一个元素
*/
public function rewind()
{
// TODO: Implement rewind() method.
return $this->key = 0;
}
}
// 客户端调用
$concreteAggregate = new ConcreteAggregate();
$concreteAggregate->add('张三');
$concreteAggregate->add('李四');
$concreteAggregate->add('王五');
$concreteIterator = $concreteAggregate->getIterator();
foreach ($concreteIterator as $concrete) {
echo $concrete . "<br>";
}
// 结果
张三
李四
王五