接下来我们继续了解Component.php
目录为：vendor/yiisoft/yii2/base/Component.php
(接上次的代码)
/**
* Sets the value of a component property.
*设置一个组件属性的值。 * This method will check in the following order and act accordingly:
*这种方法将检查以下顺序并采取相应的行动：
* - a property defined by a setter: set the property value
由一个setter定义的属性:设置属性值。 * - an event in the format of "on xyz": attach the handler to the event "xyz"
一个"on xyz"格式的事件，处理程序会附加到事件"xyz". * - a behavior in the format of "as xyz": attach the behavior named as "xyz"
一个"as xyz"格式的行为，此行为会附加到名字为"xyz"的行为后面。 * - a property of a behavior: set the behavior property value
*一个行为的属性：设置行为的属性值
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `$component->property = $value;`.
不要直接调用此方法，因为它是一个PHP魔术方法,当执行 $component->proerty = $value 时被调用。
* @param string $name the property name or the event name
属性名称或事件名称为字符型 * @param mixed $value the property value
$value为混合型 * @throws UnknownPropertyException if the property is not defined
如果没有定义属性，抛出一个异常信息。 * @throws InvalidCallException if the property is read-only.
如果属性为只读，抛出一个异常信息。 * @see __get()
*/
public function __set($name, $value)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) { //如果$setter这个方法在此类中被调用，返回true,没有返回false.
// set property
$this->$setter($value); //调用$setter方法。
return;
} elseif (strncmp($name, 'on ', 3) === 0) {//比较$name和'on '前3个字符，如果前三个字符相等，即当$name 是 'on '格式的时候，
// on event: attach event handler
$this->on(trim(substr($name, 3)), $value);//执行on 方法，用来添加附加事件。
return;
} elseif (strncmp($name, 'as ', 3) === 0) {//比较$name和'as '前3个字符，如果前三个字符相等，即当$name是 'as '格式的时候，
// as behavior: attach behavior
$name = trim(substr($name, 3));
$this->attachBehavior($name, $value instanceof Behavior ? $value : Yii::createObject($value)); //附加行为。$name 和 $value为参数，后面为三元运算，如果$value这个对象是Behavior类的一个实例，取$value为参数，否则
静态调用Yii方法创造一个新的对象。
return;
} else {
// behavior property
$this->ensureBehaviors(); //附加一个新的事件。
foreach ($this->_behaviors as $behavior) {
if ($behavior->canSetProperty($name)) {//如果参数返回为真，$behavior->$name = $value,定义属性。
$behavior->$name = $value;
return;
}
}
}
if (method_exists($this, 'get' . $name)) { //如果'get'.$name这个方法属于这个类，那么就抛出一个信息"设置只读属性".
throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
} else { //如果不属于这个类，就抛出一个信息"设置未知属性".
throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
}
}
/**
* Checks if a property is set, i.e. defined and not null.
检查属性设置，即定义,not null。
* This method will check in the following order and act accordingly:
* 这种方法将检查以下顺序并采取相应的行动：
* - a property defined by a setter: return whether the property is set
通过一个setter定义的属性：返回属性是否设置
* - a property of a behavior: return whether the property is set
一个行为的属性:返回属性是否设置 * - return `false` for non existing properties
* 对于非现有的属性返回false.
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `isset($component->property)`.
不要直接调用此方法，因为它是一个PHP魔术方法，当执行isset($component->property)时此魔术方法会被调用。
* @param string $name the property name or the event name
* @return boolean whether the named property is set
属性是否被设置返回boolean值。 * @see http://php.net/manual/en/function.isset.php
*/
public function __isset($name)
{
$getter = 'get' . $name;
if (method_exists($this, $getter)) { //如果$getter方法不存在此类当中，返回这个方法，使他不为null.
return $this->$getter() !== null;
} else {
// behavior property
$this->ensureBehaviors(); //否则附加一个时间。
foreach ($this->_behaviors as $behavior) {//遍历行为，如果此方法返回为真，返回这个属性使他不为null.
if ($behavior->canGetProperty($name)) {
return $behavior->$name !== null;
}
}
}
return false;
}
/**
* Sets a component property to be null.
设置一个组件的属性为null。
* This method will check in the following order and act accordingly:
*这种方法将检查以下顺序并采取相应的行动：
* - a property defined by a setter: set the property value to be null
通过一个setter定义的属性：属性值设置为空
* - a property of a behavior: set the property value to be null
*一个行为的属性：属性值设置为空
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `unset($component->property)`.
不要直接调用此方法，因为它是一个PHP魔术方法,当执行'unset($component->property)'时此魔术方法会被调用。
* @param string $name the property name
* @throws InvalidCallException if the property is read only.//如果这个属性为只读的话抛出一个信息。
* @see http://php.net/manual/en/function.unset.php
*/
public function __unset($name)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) { //如果$setter方法存在这个类里面的话，执行$this->$setter(null)方法。
$this->$setter(null);
return;
} else {
// behavior property
$this->ensureBehaviors(); //附加事件
foreach ($this->_behaviors as $behavior) {
if ($behavior->canSetProperty($name)) {//遍历行为事件，如果为真的话，使$behavior->$name = null.返回。
$behavior->$name = null;
return;
}
}
}
throw new InvalidCallException('Unsetting an unknown or read-only property: ' . get_class($this) . '::' . $name);//否则抛出信息"重置一个未知的或只读属性".
}
/**
* Calls the named method which is not a class method.
*调用方法名，不是一个类的方法。
* This method will check if any attached behavior has
* the named method and will execute it if available.
//此方法将检查是否有附加的行为有
命名方法（如果可用）将执行它。
* 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.
//不要直接调用此方法，因为他是一个PHP魔术方法，当一个未知方法执行时此魔术方法会被调用。
* @param string $name the method name
* @param array $params method parameters
* @return mixed the method return value
* @throws UnknownMethodException when calling unknown method
*/
public function __call($name, $params)
{
$this->ensureBehaviors();//附加事件
foreach ($this->_behaviors as $object) {
if ($object->hasMethod($name)) {
return call_user_func_array([$object, $name], $params);//用一个数组作为参数调用一个回调函数，返回值为回调函数执行的结果或者为false。
}
}
throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()"); //抛出一个信息，调用未知方法.
}
/**
* This method is called after the object is created by cloning an existing one.
* It removes all behaviors because they are attached to the old object.
*/
通过克隆现有创建的对象后，此方法会被调用。
他将会消除所有的行为因为它连接到了旧对象。
public function __clone()
{
$this->_events = []; //事件为空数组。
$this->_behaviors = null;//行为为null.
}
/**
* Returns a value indicating whether a property is defined for this component.
*返回一个指示属性是否为此组件定义的值。 * A property is defined if:
*一个被定义的属性，如果: *
* - the class has a getter or setter method associated with the specified name
*该类具有与指定名称关联的getter或setter方法 * (in this case, property name is case-insensitive);
*（在这种情况下，属性名称不区分大小写）; * - the class has a member variable with the specified name (when `$checkVars` is true);
*该类具有指定名称的成员变量（当`$ checkVars`为true） * - an attached behavior has a property of the given name (when `$checkBehaviors` is true).
*一个附加行为具有给定的名称的属性（当`$checkBehaviors`为true）。
* @param string $name the property name
* @param boolean $checkVars whether to treat member variables as properties
* @param boolean $checkBehaviors whether to treat behaviors' properties as properties of this component
* @return boolean whether the property is defined
* @see canGetProperty()
* @see canSetProperty()
*/
public function hasProperty($name, $checkVars = true, $checkBehaviors = true)
{
return $this->canGetProperty($name, $checkVars, $checkBehaviors) || $this->canSetProperty($name, false, $checkBehaviors);