设计模式之迭代器模式

<?php

/**

迭代器模式



迭代的使用任何数据类型的数据



php提供了两个接口

**/





/**

 * Interator在内部迭代自己的类的接口

 *

 * Iterator extends Traversable {

        abstract public mixed current ( void )

        abstract public scalar key ( void )

        abstract public void next ( void )

        abstract public void rewind ( void )

        abstract public boolean valid ( void )

    }



 *

 */





/*

 * IteratorAggregate  创建外部迭代器的接口

 *

 * IteratorAggregate extends Traversable {

        abstract public Traversable getIterator ( void )

    }

 *

 *

 *

 *

 */



class A{

    private $_name;

    public function __construct($name){

        $this->_name = $name;

    }

}



class myIterator implements Iterator

{

    private $_p;

    private $_data;



    public function __construct(){

        $this->_data = array(new A("apple"), new A("banana"), new A("blow"));

        $this->_p = 0;

    }



    public function current()

    {

        return array_key_exists($this->_p, $this->_data)

                ? $this->_data[$this->_p] : false;

    }

    public function key()

    {

        return $this->_p;

    }

    public function next()

    {

        $this->_p++;

    }



    public function rewind()

    {

        $this->_p = 0;

    }

    public function valid()

    {

        return array_key_exists($this->_p, $this->_data);

    }

}



$test = new myIterator();



foreach ($test as $key => $value){

    echo "$key => ";

    var_dump($value);

    echo "\n";

}





class myIterator2 implements IteratorAggregate

{

    private $_data;



    public function __construct()

    {

        $this->_data = array(new A("apple"), new A("banana"), new A("blow"));

    }



    public function getIterator()

    {

        //if $this->_data change with $this it will iterator the property

        return new ArrayIterator($this->_data);

    }

}

$test = new myIterator2();



foreach ($test as $key => $value){

    echo "$key => ";

    var_dump($value);

    echo "\n";

}