yii2框架随笔7

继续解读Object.php

/**
     * Calls the named method which is not a class method.
     *
     * 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
     * @param array $params method parameters
     * @throws UnknownMethodException when calling unknown method
     * @return mixed the method return value
     */
    public function __call($name, $params)
    {
        throw new UnknownMethodException('Calling unknown method: ' . get_class($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 the property name
     * @param boolean $checkVars whether to treat member variables as properties
     * @return boolean whether the property is defined
     * @see canGetProperty()
     * @see canSetProperty()
     */
    public function hasProperty($name, $checkVars = true)
    {
        return $this->canGetProperty($name, $checkVars) || $this->canSetProperty($name, false);
    }
    /**
     * Returns a value indicating whether a property can be read.
     * 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)
    {
       
        return method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name);
    }
    /**
     * Returns a value indicating whether a property can be set.
     * A property is writable if:
     *
     * - the class has a setter method associated with the specified name
     *   (in this case, property name is case-insensitive);
     * - the class has a member variable with the specified name (when `$checkVars` is true);
     *

     *
     * @param string $name the property name
     * @param boolean $checkVars whether to treat member variables as properties
     * @return boolean whether the property can be written
     * @see canGetProperty()
     */
    public function canSetProperty($name, $checkVars = true)
    {
        return method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name);
    }
    /**
     * Returns a value indicating whether a method is defined.
     *
     * 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 $name the method name
     * @return boolean whether the method is defined
     */
    public function hasMethod($name)
    {
        return method_exists($this, $name);
    }
}(Object.php完结)

接下来接续了解Component.php

/**
     * Returns a value indicating whether there is any handler attached to the named event.
     *
     * 判断 _events 中的一个 event 是否具有 handler
     * @param string $name the event name
     * @return boolean whether there is any handler attached to the event.
     */
    public function hasEventHandlers($name)
    {
        $this->ensureBehaviors();
        // _events 中存在 $name 的 event 或者 $name 的 event 是否含有该对象所在的类的 handler
        return !empty($this->_events[$name]) || Event::hasHandlers($this, $name);
    }

/**
     * Detaches an existing event handler from this component.
     * This method is the opposite of [[on()]].
　　　*拆离此组件现有的事件处理程序。
     * @param string $name event name
     * @param callable $handler the event handler to be removed.
     * If it is null, all handlers attached to the named event will be removed.
     * @return boolean if a handler is found and detached
     * @see on()
     */
    public function off($name, $handler = null)
    {
        // 保证 behaviors 都加载进来了
        $this->ensureBehaviors();
        // 相应的事件不存在，就返回false
        if (empty($this->_events[$name])) {
            return false;
        }
        // 没有handler，就意味着要全部去掉
        if ($handler === null) {
            unset($this->_events[$name]);
            return true;
        } else {
            $removed = false;
            foreach ($this->_events[$name] as $i => $event) {
                // $event[0]是handler，$event[1]是数据
                if ($event[0] === $handler) {
                    unset($this->_events[$name][$i]);
                    $removed = true;
                }
            }
            if ($removed) {
                // 如果有移出事件的handler，就需要重新构建以下索引，否则会出现index为1,3,4的情况
                $this->_events[$name] = array_values($this->_events[$name]);
            }
            return $removed;
        }
    }

/**
     * Triggers an event.
　　　*触发事件
     * This method represents the happening of an event. It invokes
     * all attached handlers for the event including class-level handlers.
　　　*这种方法代表事件的发生，他会触发所有连接的处理程序，包括类级别处理该事件。
     * @param string $name the event name
     * @param Event $event the event parameter. If not set, a default [[Event]] object will be created.
     */
    public function trigger($name, Event $event = null)
    {
        // 保证 behaviors 都加载进来了
        $this->ensureBehaviors();
        if (!empty($this->_events[$name])) {
            // 构建Event对象，为传入到handler函数中做准备
            if ($event === null) {
                $event = new Event;
            }
            if ($event->sender === null) {
                $event->sender = $this;
            }
            $event->handled = false;
            $event->name = $name;
            foreach ($this->_events[$name] as $handler) {
                // 给event的data属性赋值
                $event->data = $handler[1];
                // handler的函数中传入了一个Event对象
                call_user_func($handler[0], $event);
                // stop further handling if the event is handled
                // 事件是否被handle，当handled被设置为true时，执行到这个event的时候，会停止，并忽略剩下的event
                if ($event->handled) {
                    return;
                }
            }
        }
        // invoke class-level attached handlers
        // 触发class级别的handler
        Event::trigger($this, $name, $event);
    }