PHP面向对象深入研究之【了解类】与【反射API】

了解类

class_exists验证类是否存在

<?php
// TaskRunner.php

$classname = "Task";
$path = "tasks/{$classname}.php";
if ( ! file_exists( $path ) ) {
    throw new Exception( "No such file as {$path}" ); //抛出异常,类文件不存在
}
require_once( $path );
$qclassname = "tasks\\$classname";
if ( ! class_exists( $qclassname ) ) {
    throw new Exception( "No such class as $qclassname" ); //抛出异常,类不存在Fatal error: Uncaught exception 'Exception' with message 'No such class as tasks\Task'
Stack trace:
#0 {main}
}
$myObj = new $qclassname();
$myObj->doSpeak();

?>

get_class 检查对象的类 instanceof 验证对象是否属于某个类

<?php
class CdProduct {}

function getProduct() {
    return new CdProduct(    "Exile on Coldharbour Lane",
                                "The", "Alabama 3", 10.99, 60.33 ); // 返回一个类对象
}

$product = getProduct();
if ( get_class( $product ) == 'CdProduct' ) {
    print "\$product is a CdProduct object\n";
}

?>

<?php
class CdProduct {}

function getProduct() {
    return new CdProduct(    "Exile on Coldharbour Lane",
                                "The", "Alabama 3", 10.99, 60.33 );
}

$product = getProduct();
if ( $product instanceof CdProduct ) {
    print "\$product is a CdProduct object\n";
}
?>

get_class_methods 得到类中所有的方法列表,只获取public的方法，protected，private的方法获取不到。默认的就是public。

<?php

class CdProduct {
    function __construct() { }
    function getPlayLength() { }
    function getSummaryLine() { }
    function getProducerFirstName() { }
    function getProducerMainName() { }
    function setDiscount() { }
    function getDiscount() { }
    function getTitle() { }
    function getPrice() { }
    function getProducer() { }
}

print_r( get_class_methods( 'CdProduct' ) );

?>
output:
Array
(
    [0] => __construct
    [1] => getPlayLength
    [2] => getSummaryLine
    [3] => getProducerFirstName
    [4] => getProducerMainName
    [5] => setDiscount
    [6] => getDiscount
    [7] => getTitle
    [8] => getPrice
    [9] => getProducer
)

更多验证

<?php
class ShopProduct {}
interface incidental {};

class CdProduct extends ShopProduct implements incidental {
    public $coverUrl;
    function __construct() { }
    function getPlayLength() { }
    function getSummaryLine() { }
    function getProducerFirstName() { }
    function getProducerMainName() { }
    function setDiscount() { }
    function getDiscount() { }
    function getTitle() { return "title\n"; }
    function getPrice() { }
    function getProducer() { }
}

function getProduct() {
    return new CdProduct();
}

$product = getProduct(); // acquire an object
$method = "getTitle";     // define a method name
print $product->$method();  // invoke the method
if ( in_array( $method, get_class_methods( $product ) ) ) {
    print $product->$method();  // invoke the method
}
if ( is_callable( array( $product, $method) ) ) {
    print $product->$method();  // invoke the method
}
if ( method_exists( $product, $method ) ) {
    print $product->$method();  // invoke the method
}
print_r( get_class_vars( 'CdProduct' ) );

if ( is_subclass_of( $product, 'ShopProduct' ) ) {
    print "CdProduct is a subclass of ShopProduct\n";
}

if ( is_subclass_of( $product, 'incidental' ) ) {
    print "CdProduct is a subclass of incidental\n";
}

if ( in_array( 'incidental', class_implements( $product )) ) {
    print "CdProduct is an interface of incidental\n";
}

?>
output:
title
title
title
title
Array
(
    [coverUrl] =>
)
CdProduct is a subclass of ShopProduct
CdProduct is a subclass of incidental
CdProduct is an interface of incidental

__call方法

<?php

class OtherShop {
    function thing() {
        print "thing\n";
    }
    function andAnotherthing() {
        print "another thing\n";
    }
}

class Delegator {
    private $thirdpartyShop;
    function __construct() {
        $this->thirdpartyShop = new OtherShop();
    }

    function __call( $method, $args ) { // 当调用未命名方法时执行call方法
        if ( method_exists( $this->thirdpartyShop, $method ) ) {
            return $this->thirdpartyShop->$method( );
        }
    }
}

$d = new Delegator();
$d->thing();

?>
output:
thing

传参使用

<?php

class OtherShop {
    function thing() {
        print "thing\n";
    }
    function andAnotherthing( $a, $b ) {
        print "another thing ($a, $b)\n";
    }
}

class Delegator {
    private $thirdpartyShop;
    function __construct() {
        $this->thirdpartyShop = new OtherShop();
    }

    function __call( $method, $args ) {
        if ( method_exists( $this->thirdpartyShop, $method ) ) {
            return call_user_func_array(
                        array( $this->thirdpartyShop,
                            $method ), $args );
        }
    }
}

$d = new Delegator();
$d->andAnotherThing( "hi", "hello" );

?>
output:
another thing (hi, hello)

反射API

fullshop.php
<?php
class ShopProduct {
    private $title;
    private $producerMainName;
    private $producerFirstName;
    protected $price;
    private $discount = 0;

    public function __construct(   $title, $firstName,
                            $mainName, $price ) {
        $this->title             = $title;
        $this->producerFirstName = $firstName;
        $this->producerMainName  = $mainName;
        $this->price             = $price;
    }

    public function getProducerFirstName() {
        return $this->producerFirstName;
    }

    public function getProducerMainName() {
        return $this->producerMainName;
    }

    public function setDiscount( $num ) {
        $this->discount=$num;
    }

    public function getDiscount() {
        return $this->discount;
    }

    public function getTitle() {
        return $this->title;
    }

    public function getPrice() {
        return ($this->price - $this->discount);
    }

    public function getProducer() {
        return "{$this->producerFirstName}".
               " {$this->producerMainName}";
    }

    public function getSummaryLine() {
        $base  = "{$this->title} ( {$this->producerMainName}, ";
        $base .= "{$this->producerFirstName} )";
        return $base;
    }
}

class CdProduct extends ShopProduct {
    private $playLength = 0;

    public function __construct(   $title, $firstName,
                            $mainName, $price, $playLength=78 ) {
        parent::__construct(    $title, $firstName,
                                $mainName, $price );
        $this->playLength = $playLength;
    }

    public function getPlayLength() {
        return $this->playLength;
    }

    public function getSummaryLine() {
        $base = parent::getSummaryLine();
        $base .= ": playing time - {$this->playLength}";
        return $base;
    }

}

class BookProduct extends ShopProduct {
    private $numPages = 0;

    public function __construct(   $title, $firstName,
                            $mainName, $price, $numPages ) {
        parent::__construct(    $title, $firstName,
                                $mainName, $price );
        $this->numPages = $numPages;
    }

    public function getNumberOfPages() {
        return $this->numPages;
    }

    public function getSummaryLine() {
        $base = parent::getSummaryLine();
        $base .= ": page count - {$this->numPages}";
        return $base;
    }

    public function getPrice() {
        return $this->price;
    }
}

/*
$product1 = new CdProduct("cd1", "bob", "bobbleson", 4, 50 );
print $product1->getSummaryLine()."\n";
$product2 = new BookProduct("book1", "harry", "harrelson", 4, 30 );
print $product2->getSummaryLine()."\n";
*/
?>

<?php
require_once "fullshop.php";
$prod_class = new ReflectionClass( 'CdProduct' );
Reflection::export( $prod_class );
?>

output:
Class [ <user> class CdProduct extends ShopProduct ] {
  @@ D:\xampp\htdocs\popp-code\5\fullshop.php 53-73

  - Constants [0] {
  }

  - Static properties [0] {
  }

  - Static methods [0] {
  }

  - Properties [2] {
    Property [ <default> private $playLength ]
    Property [ <default> protected $price ]
  }

  - Methods [10] {
    Method [ <user, overwrites ShopProduct, ctor> public method __construct ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 56 - 61

      - Parameters [5] {
        Parameter #0 [ <required> $title ]
        Parameter #1 [ <required> $firstName ]
        Parameter #2 [ <required> $mainName ]
        Parameter #3 [ <required> $price ]
        Parameter #4 [ <optional> $playLength = 78 ]
      }
    }

    Method [ <user> public method getPlayLength ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 63 - 65
    }

    Method [ <user, overwrites ShopProduct, prototype ShopProduct> public method getSummaryLine ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 67 - 71
    }

    Method [ <user, inherits ShopProduct> public method getProducerFirstName ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 17 - 19
    }

    Method [ <user, inherits ShopProduct> public method getProducerMainName ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 21 - 23
    }

    Method [ <user, inherits ShopProduct> public method setDiscount ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 25 - 27

      - Parameters [1] {
        Parameter #0 [ <required> $num ]
      }
    }

    Method [ <user, inherits ShopProduct> public method getDiscount ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 29 - 31
    }

    Method [ <user, inherits ShopProduct> public method getTitle ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 33 - 35
    }

    Method [ <user, inherits ShopProduct> public method getPrice ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 37 - 39
    }

    Method [ <user, inherits ShopProduct> public method getProducer ] {
      @@ D:\xampp\htdocs\popp-code\5\fullshop.php 41 - 44
    }
  }
}

点评：把类看的透彻的一塌糊涂，比var_dump强多了。哪些属性，继承了什么类。类中的方法哪些是自己的，哪些是重写的，哪些是继承的，一目了然。

查看类数据

<?php
require_once("fullshop.php");

function classData( ReflectionClass $class ) {
  $details = "";
  $name = $class->getName();
  if ( $class->isUserDefined() ) {
    $details .= "$name is user defined\n";
  }
  if ( $class->isInternal() ) {
    $details .= "$name is built-in\n";
  }
  if ( $class->isInterface() ) {
    $details .= "$name is interface\n";
  }
  if ( $class->isAbstract() ) {
    $details .= "$name is an abstract class\n";
  }
  if ( $class->isFinal() ) {
    $details .= "$name is a final class\n";
  }
  if ( $class->isInstantiable() ) {
    $details .= "$name can be instantiated\n";
  } else {
    $details .= "$name can not be instantiated\n";
  }
  return $details;
}

$prod_class = new ReflectionClass( 'CdProduct' );
print classData( $prod_class );

?>
output:
CdProduct is user defined
CdProduct can be instantiated

查看方法数据

<?php
require_once "fullshop.php";
$prod_class = new ReflectionClass( 'CdProduct' );
$methods = $prod_class->getMethods();

foreach ( $methods as $method ) {
  print methodData( $method );
  print "\n----\n";
}

function methodData( ReflectionMethod $method ) {
  $details = "";
  $name = $method->getName();
  if ( $method->isUserDefined() ) {
    $details .= "$name is user defined\n";
  }
  if ( $method->isInternal() ) {
    $details .= "$name is built-in\n";
  }
  if ( $method->isAbstract() ) {
    $details .= "$name is abstract\n";
  }
  if ( $method->isPublic() ) {
    $details .= "$name is public\n";
  }
  if ( $method->isProtected() ) {
    $details .= "$name is protected\n";
  }
  if ( $method->isPrivate() ) {
    $details .= "$name is private\n";
  }
  if ( $method->isStatic() ) {
    $details .= "$name is static\n";
  }
  if ( $method->isFinal() ) {
    $details .= "$name is final\n";
  }
  if ( $method->isConstructor() ) {
    $details .= "$name is the constructor\n";
  }
  if ( $method->returnsReference() ) {
    $details .= "$name returns a reference (as opposed to a value)\n";
  }
  return $details;
}

?>
output:
__construct is user defined
__construct is public
__construct is the constructor

----
getPlayLength is user defined
getPlayLength is public

----
getSummaryLine is user defined
getSummaryLine is public

----
getProducerFirstName is user defined
getProducerFirstName is public

----
getProducerMainName is user defined
getProducerMainName is public

----
setDiscount is user defined
setDiscount is public

----
getDiscount is user defined
getDiscount is public

----
getTitle is user defined
getTitle is public

----
getPrice is user defined
getPrice is public

----
getProducer is user defined
getProducer is public

获取构造函数参数情况

<?php
require_once "fullshop.php";

$prod_class = new ReflectionClass( 'CdProduct' );
$method = $prod_class->getMethod( "__construct" );
$params = $method->getParameters();

foreach ( $params as $param ) {
    print argData( $param )."\n";
}

function argData( ReflectionParameter $arg ) {
  $details = "";
  $declaringclass = $arg->getDeclaringClass();
  $name  = $arg->getName();
  $class = $arg->getClass();
  $position = $arg->getPosition();
  $details .= "\$$name has position $position\n";
  if ( ! empty( $class )  ) {
    $classname = $class->getName();
    $details .= "\$$name must be a $classname object\n";
  }

  if ( $arg->isPassedByReference() ) {
    $details .= "\$$name is passed by reference\n";
  }

  if ( $arg->isDefaultValueAvailable()  ) {
    $def = $arg->getDefaultValue();
    $details .= "\$$name has default: $def\n";
  }

  if ( $arg->allowsNull()  ) {
    $details .= "\$$name can be null\n";
  }

  return $details;
}
?>

output:
$title has position 0
$title can be null

$firstName has position 1
$firstName can be null

$mainName has position 2
$mainName can be null

$price has position 3
$price can be null

$playLength has position 4
$playLength has default: 78
$playLength can be null