继承中的__set和__get重载
提问于 2014-10-21 06:51:03
我正在使用PHP实现OOP设计。我想知道PHP如何为其神奇的方法(如__get和__set )处理继承。
class Foo
{
protected $property1;
public function __get($name)
{
if ($name == "property1")
{
// do some logic
return $result; // may be null
}
return;
}
public function __set($name, $value)
{
if ($name == "property1")
{
// do some logic
return $result; // may be null
}
result;
}
}现在用于扩展Foo
class Bar extends Foo
{
protected $property2;
public function __get($name)
{
if (($result = parent::__get($name)) !== null)
return $result; // may be null
if ($name == "property2")
{
// do some logic
return $result; // may be null
}
return;
}
public function __set($name, $value)
{
if (($result = parent::__set($name, $value)) !== null)
return $result; // may be null
if ($name == "property2")
{
// do some logic
return $result; // may be null
}
return;
}
}当PHP将null作为一个函数的结果返回时，没有什么可返回的.这可能导致parent::__get()或parent::__set()是否真实返回null，还是返回时不带值，从而导致开销。
现在，如果PHP首先考虑static::_get()和static::__set()，并在失败时退回到parent版本，则可以将其简化为：
class Bar extends Foo
{
protected $property2;
public function __get($name)
{
if ($name = "property2")
{
// do some logic
return $result; // may be null
}
return;
}
public function __set($name, $value)
{
if ($name = "property2")
{
// do some logic
return $result; // may be null
}
return;
}
}我无法在当前实现上测试它，因为上下文中的类操作生产、活动数据库。哪个是正确的实现？
谢谢!
回答 2
Stack Overflow用户
回答已采纳
发布于 2014-10-21 07:27:04
只使用魔术方法作为代理方法。您的代码将更加简洁，您不需要处理继承带来的问题。
简单的例子：
class Foo
{
protected $property1;
public function setProperty1($property1)
{
// do some logic
$this->property1 = $property1;
return $this;
}
public function getProperty1()
{
// do some logic
return $this->property1;
}
public function __get($name)
{
$method = 'get' . ucfirst($name);
if (method_exists($this, $method)) {
return $this->$method();
}
}
public function __set($name, $value)
{
$method = 'set' . ucfirst($name);
if (method_exists($this, $method)) {
$this->$method($value);
}
}
}
class Bar extends Foo
{
protected $property2;
public function setProperty2($property2)
{
// do some logic
$this->property2 = $property2;
return $this;
}
public function getProperty2()
{
// do some logic
return $this->property2;
}
}示例呼叫：
$bar = new Bar;
$bar->property1 = 'foo';
$bar->property2 = 'bar';
var_dump($bar);Stack Overflow用户
发布于 2014-10-21 07:25:36
我已经成功地创建了一个孤立的环境并测试了这两种方法。
方法1
class Foo
{
protected $property1;
public function __get($name)
{
if ($name == "name")
{
echo "been here @line(" . __LINE__ . ") Foo::__get('$name') <br/>";
$result = $this->property1;
return $result; // may be null
}
return;
}
public function __set($name, $value)
{
if ($name == "name")
{
echo "been here @line(" . __LINE__ . ") Foo::__set('$name', '$value') <br/>";
$result = $this->property1 = $value;
return $result; // may be null
}
return;
}
}
class Bar extends Foo
{
protected $property2;
public function __get($name)
{
if ($name == "place")
{
echo "been here @line(" . __LINE__ . ") Bar::__get('$name') <br/>";
$result = $this->property2;
return $result; // may be null
}
return;
}
public function __set($name, $value)
{
if ($name == "place")
{
echo "been here @line(" . __LINE__ . ") Bar::__set('$name', '$value') <br/>";
$result = $this->property2 = $value;
return $result; // may be null
}
return;
}
}
$bar = new Bar;
$bar->name = 'Alice';
$bar->place = 'Wonderland';
echo "done that: '{$bar->name} in {$bar->place}'";上述代码的结果如下：
been here @line(59) Bar::__set('place', 'Wonderland')
been here @line(43) Bar::__get('place')
done that: ' in Wonderland'这显然不是答案。
方法2
class Foo
{
protected $property1;
public function __get($name)
{
if ($name == "name")
{
echo "been here @line(" . __LINE__ . ") Foo::__get('$name') <br/>";
$result = $this->property1;
return $result; // may be null
}
return;
}
public function __set($name, $value)
{
if ($name == "name")
{
echo "been here @line(" . __LINE__ . ") Foo::__set('$name', '$value') <br/>";
$result = $this->property1 = $value;
return $result; // may be null
}
return;
}
}
class Bar extends Foo
{
protected $property2;
public function __get($name)
{
if (($result = parent::__get($name)) !== null)
{
echo "been here @line(" . __LINE__ . ") parent::__get('$name') <br/>";
return $result; // may be null
}
if ($name == "place")
{
echo "been here @line(" . __LINE__ . ") Bar::__get('$name') <br/>";
$result = $this->property2;
return $result; // may be null
}
return;
}
public function __set($name, $value)
{
if (($result = parent::__set($name, $value)) !== null)
{
echo "been here @line(" . __LINE__ . ") parent::__set('$name', '$value') <br/>";
return $result; // may be null
}
if ($name == "place")
{
echo "been here @line(" . __LINE__ . ") Bar::__set('$name', '$value') <br/>";
$result = $this->property2 = $value;
return $result; // may be null
}
return;
}
}
$bar = new Bar;
$bar->name = 'Alice';
$bar->place = 'Wonderland';
echo "done that: '{$bar->name} in {$bar->place}'";其结果是：
been here @line(22) Foo::__set('name', 'Alice')
been here @line(54) parent::__set('name', 'Alice')
been here @line(59) Bar::__set('place', 'Wonderland')
been here @line(11) Foo::__get('name')
been here @line(38) parent::__get('name')
been here @line(43) Bar::__get('place')
done that: 'Alice in Wonderland'这是处理继承时重载__get和__set魔术函数的正确答案，但这有开销。这是一个解决办法，但有没有更好的解决办法？
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/26489665
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