yii\base\Object代码详解
<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/ namespace yii\base; use Yii; /**
* Object is the base class that implements the *property* feature.
* Object 是一个实现属性功能的基类
* A property is defined by a getter method (e.g. `getLabel`), and/or a setter method (e.g. `setLabel`). For example,
* 定义了getter和setter方法。例如：
* the following getter and setter methods define a property named `label`:
*
* ~~~
* private $_label;
*
* public function getLabel()
* {
* return $this->_label;
* }
*
* public function setLabel($value)
* {
* $this->_label = $value;
* }
* ~~~
*
* Property names are *case-insensitive*.
* 属性名大小写敏感
* A property can be accessed like a member variable of an object. Reading or writing a property will cause the invocation
* of the corresponding getter or setter method. For example,
* 可以访问对象的属性，如对象的成员变量。读或写一个属性将导致调用相应的getter或setter方法
* ~~~
* // equivalent to $label = $object->getLabel();
* $label = $object->label;
* // equivalent to $object->setLabel('abc');
* $object->label = 'abc';
* ~~~
*
* If a property has only a getter method and has no setter method, it is considered as *read-only*. In this case, trying
* to modify the property value will cause an exception.
* 如果一个属性只有getter方法，就只能读，如果写会出现异常。
* One can call [[hasProperty()]], [[canGetProperty()]] and/or [[canSetProperty()]] to check the existence of a property.
* 通过hasProperty canGetProperty或canSetProperty 检查属性是否存在
* Besides the property feature, Object also introduces an important object initialization life cycle. In particular,
* creating an new instance of Object or its derived class will involve the following life cycles sequentially:
* 除了属性特征，对象还引入了一个重要的对象初始化生命周期，
* 创建一个新的对象或其派生类的实例，将涉及下列生命周期
* 1. the class constructor is invoked;
* 2. object properties are initialized according to the given configuration;
* 3. the `init()` method is invoked.
* 调用构造函数;
* 根据给定的对象属性初始化配置;
* init()调用的方法.
* In the above, both Step 2 and 3 occur at the end of the class constructor. It is recommended that
* you perform object initialization in the `init()` method because at that stage, the object configuration
* is already applied.
* 2和3发生在类构造函数的末端。建议
* 你完成对象的初始化在` init（）`方法因为在那个阶段，对象配置已经应用。
* In order to ensure the above life cycles, if a child class of Object needs to override the constructor,
* it should be done like the following:
* 为了保证的生命周期，如果一个子类的对象需要重写构造函数，
* ~~~
* public function __construct($param1, $param2, ..., $config = [])
* {
* ...
* parent::__construct($config);
* }
* ~~~
*
* That is, a `$config` parameter (defaults to `[]`) should be declared as the last parameter
* of the constructor, and the parent implementation should be called at the end of the constructor.
* 一个配置的参数应该声明为最后一个参数，构造函数和父类的实现应该在结尾调用
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class Object
{
/**
* Returns the fully qualified name of this class. 获取静态方法调用的类名，返回类的名称
* @return string the fully qualified name of this class.
*/
public static function className()
{ //哪个类调用，就返回哪个类，
return get_called_class();
} /**
* Constructor.
* The default implementation does two things:
*
* - Initializes the object with the given configuration `$config`.
* - Call [[init()]].
*
* If this method is overridden in a child class, it is recommended that
*
* - the last parameter of the constructor is a configuration array, like `$config` here.
* - call the parent implementation at the end of the constructor.
*
* @param array $config name-value pairs that will be used to initialize the object properties
*/
public function __construct($config = [])
{
//根据$config初始化对象
if (!empty($config)) {
Yii::configure($this, $config);
}
//调用 init（）方法，用于初始化，可以被重写。
$this->init();
} /**
* Initializes the object.
* This method is invoked at the end of the constructor after the object is initialized with the
* given configuration.
* 初始化结束时调用，与给定的配置初始化。
*/
public function init()
{
} /**
* Returns the value of an object property.
*
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `$value = $object->property;`.
* 不要直接调用这个方法,因为它是一个PHP魔术方法，要隐式调用
* @param string $name the property name 属性名称
* @return mixed the property value 属性值
* @throws UnknownPropertyException if the property is not defined 属性未定义
* @throws InvalidCallException if the property is write-only 该属性写
* @see __set()
*/
public function __get($name)
{
$getter = 'get' . $name;//定义$getter
if (method_exists($this, $getter)) {
return $this->$getter();//存在方法，直接调用
} elseif (method_exists($this, 'set' . $name)) {
// 如果存在 'set' . $name 方法，就认为属性是只写
throw new InvalidCallException('Getting write-only property: ' . get_class($this) . '::' . $name);
} else {
// 否则认为该属性不存在 未定义
throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name);
}
} /**
* Sets value of an object property.
*
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `$object->property = $value;`.
* @param string $name the property name or the event name 属性或事件名称
* @param mixed $value the property value 属性值
* @throws UnknownPropertyException if the property is not defined 未定义属性
* @throws InvalidCallException if the property is read-only 属性只写
* @see __get()
*/
public function __set($name, $value)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) {
$this->$setter($value);//对象存在$setter方法，直接调用
} elseif (method_exists($this, 'get' . $name)) {
// 存在 'get' . $name 方法，就认为该属性是只读
throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
} else { // 否则认为该属性不存在 未定义
throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
}
} /**
* Checks if the named property is set (not null).
* 检查属性是否设置
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `isset($object->property)`.
*
* Note that if the property is not defined, false will be returned. 未定义返回false
* @param string $name the property name or the event name 属性名
* @return boolean whether the named property is set (not null).
*/
public function __isset($name)
{
$getter = 'get' . $name;
if (method_exists($this, $getter)) {
//由$getter获取的值不为null，该属性存在，返回true
return $this->$getter() !== null;
} else {
return false;//该属性存在，返回false
}
} /**
* Sets an object property to null.
* 设置一个属性为空
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `unset($object->property)`.
*
* Note that if the property is not defined, this method will do nothing.
* If the property is read-only, it will throw an exception.
* @param string $name the property name 属性名
* @throws InvalidCallException if the property is read only. 属性只读
*/
public function __unset($name)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) {
//如果存在，由$setter设置为null
$this->$setter(null);
} elseif (method_exists($this, 'get' . $name)) {
//如果是只读的，抛出异常
throw new InvalidCallException('Unsetting read-only property: ' . get_class($this) . '::' . $name);
}
} /**
* Calls the named method which is not a class method.
* 调用指定的方法而不是一个类方法.
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when an unknown method is being invoked.
* @param string $name the method name 方法名
* @param array $params method parameters 方法参数
* @throws UnknownMethodException when calling unknown method 调用未知方法
* @return mixed the method return value
*/
public function __call($name, $params)
{
//调用指定方法
throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()");
} /**
* Returns a value indicating whether a property is defined.
* A property is defined if:
*
* - the class has a getter or setter method associated with the specified name
* (in this case, property name is case-insensitive);
* - the class has a member variable with the specified name (when `$checkVars` is true);
* 检查查对象或类是否具有 $name 属性，如果 $checkVars 为 true，则不局限于是否有 getter或setter
* @param string $name the property name 属性名
* @param boolean $checkVars whether to treat member variables as properties 是否将成员变量作为属性对待 true/false
* @return boolean whether the property is defined 属性是否定义
* @see canGetProperty()
* @see canSetProperty()
*/
public function hasProperty($name, $checkVars = true)
{
return $this->canGetProperty($name, $checkVars) || $this->canSetProperty($name, false);
} /**
* Returns a value indicating whether a property can be read.
* 返回一个值指示是否可以读取属性.
* A property is readable if:
*
* - the class has a getter method associated with the specified name
* (in this case, property name is case-insensitive);
* - the class has a member variable with the specified name (when `$checkVars` is true);
* 检查对象或类是否能够获取 $name 属性，如果 $checkVars 为 true，则不局限于是否有 getter
* @param string $name the property name
* @param boolean $checkVars whether to treat member variables as properties
* @return boolean whether the property can be read
* @see canSetProperty()
*/
public function canGetProperty($name, $checkVars = true)
{
//是否存在该属性
return method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name);
} /**
* Returns a value indicating whether a property can be set.
* 属性是否可设置
* A property is writable if:
*
* - the class has a setter method associated with the specified name
* (in this case, property name is case-insensitive);
* - the class has a member variable with the specified name (when `$checkVars` is true);
* 检查对象或类是否能够设置 $name 属性，如果 $checkVars 为 true，则不局限于是否有 setter
*
* @param string $name the property name
* @param boolean $checkVars whether to treat member variables as properties 是否将成员变量作为属性来对待
* @return boolean whether the property can be written 是否可写
* @see canGetProperty()
*/
public function canSetProperty($name, $checkVars = true)
{
return method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name);
} /**
* Returns a value indicating whether a method is defined.
* 方法是否定义
* The default implementation is a call to php function `method_exists()`.
* You may override this method when you implemented the php magic method `__call()`.
* @param string $name the method name
* @return boolean whether the method is defined 是否具有 $name 方法
*/
public function hasMethod($name)
{
return method_exists($this, $name);
}
}