问数据持有者应该具有什么样的可见性？

EN

/**
 * Handling non existing getters and setters
 *
 * @param string $name
 * @param array $arguments
 * @throws Exception
 */
public function __call($name, $arguments)
{
    $type = substr($name, 0, 3);

    // Check if this is a getter or setter
    if (in_array($type, array('get', 'set'))) {
        $property = lcfirst(substr($name, 3));

        // Only if the property exists we can go on
        if (property_exists($this, $property)) {
            switch ($type) {
                case 'get':
                    return $this->$property;
                    break;

                case 'set':
                    $this->$property = $arguments[0];
                    return $this;
                    break;
            }
        } else {
            throw new \Exception('Unknown property "' . $property . '"');
        }
    } else {
        throw new Exception('Unknown method "' . $name . '"');
    }
}

/**
 * Magic Method for getters
 *
 * @param string $name
 * @return mixed
 */
public function __get($name)
{
    $method = 'get' . ucfirst($name);
    return $this->$method();
}

/**
 * Magic Method for setters
 *
 * @param string $name
 * @param mixed $value
 */
public function __set($name, $value)
{
    $method = 'set' . ucfirst($name);
    return $this->$method($value);
}

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