_parts[] = $part;    }    public function show() {        echo "\n PRODUCT CREATEING...
";        foreach ($this->_parts as $part) {            echo $part;            echo "
";        }    }}abstract class Builder {    abstract function build_part_A();    abstract function build_part_B();    abstract function get_result(): Product;}class Concrete_builder_one extends Builder {    private $_product = null;    public function __construct() {        $this->_product  = new Product();    }    public function build_part_A() {        $this->_product->add('PART A');    }    public function build_part_B() {        $this->_product->add('PART B');    }    public function get_result() : Product {        return $this->_product;    }}class Concrete_builder_two extends Builder {    private $_product = null;    public function __construct() {        $this->_product  = new Product();    }    public function build_part_A() {        $this->_product->add('PART X');    }    public function build_part_B() {        $this->_product->add('PART Y');    }    public function get_result() : Product {        return $this->_product;    }}class Director {    public function concrete(Builder $builder) {        $builder->build_part_A();        $builder->build_part_B();    }}//CLIENT CODE$director = new Director();$b1 = new Concrete_builder_one();$b2 = new Concrete_builder_two();$director->concrete($b1);$product1 = $b1->get_result();$product1->show();$director->concrete($b2);$product2 = $b2->get_result();$product2->show();

 

建造者模式：

　　将一个复杂对象的构建与它的表示分离，使得同样的建造过程可以创建不同的表示。

　　如果我们用了建造者模式，那么用户就只需要指定需要建造的类型就可以得到它们，而具体建造的过程和细节就不需要知道了。

　　Director，指挥者，它是构建一个使用Builder接口的对象。在Director中完成部件的装配（即建造过程）！！