Object 是一个基础类,实现了属性的功能,其基本内容如下:
namespace yii\base; use Yii; /** * Object is the base class that implements the *property* feature. * Object是一个基础类,实现了属性的功能 * A property is defined by a getter method (e.g. `getLabel`), and/or a setter method (e.g. `setLabel`). For example, * the following getter and setter methods define a property named `label`: * 属性通过getter和setter方法定义,如下面的例子 * ```php * private $_label; 定义私有的成员 * * public function getLabel() * { * return $this->_label; 通过getter方法取得_label的值 * } * * public function setLabel($value) * { * $this->_label = $value; 通过setter方法设置_label的值 * } * ``` * * Property names are *case-insensitive*. * 属性名是不区分大小写的 * 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, * 属性能够像一个成员变量一样被访问,读、写将会调用对应的getter或者setter方法 * ```php * // equivalent to $label = $object->getLabel(); * $label = $object->label; * // equivalent to $object->setLabel('abc'); * $object->label = 'abc'; * ``` * * If a property has only a getter method and has no setter method, it is considered as *read-only*. In this case, trying * to modify the property value will cause an exception. * 如果一个属性只有getter方法,那么这个属性是只读的,如果试图修改这个属性的值,将会抛出异常 * 能够调用 [[hasProperty()]], [[canGetProperty()]] and/or [[canSetProperty()]] 检查一个属性 * * @author Qiang Xue <qiang.xue@gmail.com> * @since 2.0 */ class Object implements Configurable { /** * Returns the fully qualified name of this class. * 获取静态方法调用的类名。返回类的名称,如果不是在类中调用则返回 FALSE。 * @return string the fully qualified name of this class. */ public static function className() { return get_called_class(); // get_called_class -- 后期静态绑定("Late Static Binding")类的名称 // 就是用那个类调用的这个方法,就返回那个类,返回值中带有 namespace } /** * Constructor. * The default implementation does two things: * 构造方法实现了接口Configurable,通过传入的配置初始化对象,调用init()方法 * - Initializes the object with the given configuration `$config`. * - Call [[init()]]. * * If this method is overridden in a child class, it is recommended that * 如果构造函数在子类中重写,必须调用父类的方法,且最后一个参数为配置数组 * - 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 $config 内容初始化该对象 if (!empty($config)) { Yii::configure($this, $config); } // 调用 init() 方法,继承该类的类可以重写 init 方法,用于初始化 $this->init(); } /** * Initializes the object. * 初始化对象 * This method is invoked at the end of the constructor after the object is initialized with the * given configuration. * 在构造函数的末尾调用,可以重写 init 方法,用于初始化 */ public function init() { } /** * Returns the value of an object property. * 返回对象的属性值 * Do not call this method directly as it is a PHP magic method that * will be implicitly called when executing `$value = $object->property;`. * * 魔术方法,实现 getter,在访问不存在的属性时调用,即成员变量设置为public时,不会被调用 * * @param string $name the property name * @return mixed the property value * @throws UnknownPropertyException if the property is not defined * @throws InvalidCallException if the property is write-only * @see __set() */ public function __get($name) { $getter = 'get' . $name; //构造getter方法 if (method_exists($this, $getter)) { // 对象存在 $getter 方法,就直接调用 return $this->$getter(); } elseif (method_exists($this, 'set' . $name)) { // 如果存在 'set' . $name 方法,就认为该属性是只写的,抛出异常 throw new InvalidCallException('Getting write-only property: ' . get_class($this) . '::' . $name); } else { // 否则认为该属性不存在,抛出异常 throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name); } } /** * Sets value of an object property. * 设置对象的属性值 * Do not call this method directly as it is a PHP magic method that * will be implicitly called when executing `$object->property = $value;`. * * 魔术方法,实现 setter,在访问不存在的属性时调用,即成员变量设置为public时,不会被调用 * * @param string $name the property name or the event name * @param mixed $value the property value * @throws UnknownPropertyException if the property is not defined * @throws InvalidCallException if the property is read-only * @see __get() */ public function __set($name, $value) { $setter = 'set' . $name; //构造setter方法 if (method_exists($this, $setter)) { // 对象存在 $setter 方法,就直接调用 $this->$setter($value); } elseif (method_exists($this, 'get' . $name)) { // 如果存在 'get' . $name 方法,就认为该属性是只读的,抛出异常 throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name); } else { // 否则认为该属性不存在,,抛出异常 throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name); } } /** * 检查属性是否被设置 * * 魔术方法,实现 isset,用isset() 判断对象不可见的属性时(protected/private/不存在的属性)被调用 * 基于 getter 实现,有 getter 方法的属性才算存在 * @param string $name the property name or the event name * @return boolean whether the named property is set (not null). * @see http://php.net/manual/en/function.isset.php */ public function __isset($name) { $getter = 'get' . $name; if (method_exists($this, $getter)) { // 判断是否有getter方法,且是否有返回值,有 getter 方法且获取的值不为 null,才认为该属性存在 return $this->$getter() !== null; } else { return false; } } /** * * 魔术方法,实现 unset,在注销不可见的属性时(protected/private/不存在的属性)时被调用 * 基于 setter 实现,有 setter 方法的属性才能 unset 掉 * @param string $name 属性名 * @throws InvalidCallException if the property is read only. * @see http://php.net/manual/en/function.unset.php */ public function __unset($name) { $setter = 'set' . $name; //构造setter方法 if (method_exists($this, $setter)) { // 如果setter方法存在,通过 setter 方法,将它设置为 null $this->$setter(null); } elseif (method_exists($this, 'get' . $name)) { // 如果存在 'get' . $name 方法,就认为该属性是只读的,抛出异常 throw new InvalidCallException('Unsetting read-only property: ' . get_class($this) . '::' . $name); } } /** *重写了__call()方法,在调用不存在的方法时会调用此方法,抛出异常 * @param string $name 方法名 * @param array $params 方法参数 * @throws UnknownMethodException when calling unknown method 异常 * @return mixed the method return value */ public function __call($name, $params) { throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()"); } /** * * 检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/setter * * @param string $name 属性名 * @param boolean $checkVars 是否检查成员变量,默认为true * @return boolean 属性是否被定义 * @see canGetProperty() * @see canSetProperty() */ public function hasProperty($name, $checkVars = true) { return $this->canGetProperty($name, $checkVars) || $this->canSetProperty($name, false); } /** * * 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 属性名 * @param boolean $checkVars 是否检查成员变量,默认为true * @return boolean 属性是否可读 * @see canSetProperty() */ public function canGetProperty($name, $checkVars = true) { // property_exists — 检查对象或类是否具有该属性 return method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name); } /** * * 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 属性名 * @param boolean $checkVars 是否检查成员变量,默认为true * @return boolean 属性是否可写 * @see canGetProperty() */ public function canSetProperty($name, $checkVars = true) { return method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name); } /** * 调用php的 `method_exists()`函数. * You may override this method when you implemented the php magic method `__call()`. * * 检查对象或类是否具有 $name 方法 * * @param string $name 方法名 * @return boolean 方法是否被定义 */ public function hasMethod($name) { return method_exists($this, $name); } }