WordPress Options Class with Support for storing and retrieving JSON

wordpress-options-json.php

<?php
class My_Plugin_Options {
	var $options;
	var $option_name;
	var $is_site_option;    // Are we using Multisite and saving to global options?

	function My_Plugin_Options($option_name, $is_site_options = false){
		$this->option_name = $option_name;
		$this->is_site_option = $is_site_options;
		if($this->is_site_option){
			$this->options = get_site_option($this->option_name);
		} else {
			$this->options = get_option($this->option_name);
		}
        
		// Check if options are JSON
		if(!is_array($this->options)){
			$temp_options = json_decode($this->options);
			if(json_last_error() == JSON_ERROR_NONE && !empty($temp_options)){
				$this->options = $temp_options;
			}

			if(empty($this->options)){
				$this->options = array();
			}
		}
	}
 
	function __get($key){
		if(is_array($this->options)){
			if(isset($this->options[$key])){
				return $this->options[$key];
			}
		} elseif(is_object($this->options)){
			if(isset($this->options->{$key})){
				return $this->options->{$key};
			}
		}

		return false;
	}
 
	function __set($key, $value){
		if(is_array($this->options)){
			$this->options[$key] = $value;
		} elseif(is_object($this->options)){
			$this->options->{$key} = $value;
		} else {
			// Do nothing
		}
	}
 
	function __isset($key){
		if(is_array($this->options)){
			return array_key_exists($key, $this->options);
		} elseif(is_object($this->options)){
			return property_exists($this->options, $key);
		} else {
			return false;
		}
	}
 
	function save(){
		if($this->is_site_option){
			update_site_option($this->option_name, json_encode($this->options));
		} else {
			update_option($this->option_name, json_encode($this->options));
		}
	}
}
?>

My another question :D! I can set nested jSON like this:

• $this->options->my_setting3 = array('a3'=>'A3','b3'=>'B3');

My question is how I can modify value 'A3' of 'a3' key only...

Thanks!