# Change the state of instancied class by a method with json file
**URL:** https://forum.crystal-lang.org/t/change-the-state-of-instancied-class-by-a-method-with-json-file/7003
**Category:** Help & Support
**Created:** [July 8, 2024, 6:39pm UTC](https://forum.crystal-lang.org/t/change-the-state-of-instancied-class-by-a-method-with-json-file/7003 "2024-07-08T18:39:04Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Fulgurance](https://forum.crystal-lang.org/u/Fulgurance)
#### Post date: [July 8, 2024, 6:39pm UTC](https://forum.crystal-lang.org/t/change-the-state-of-instancied-class-by-a-method-with-json-file/7003/1 "2024-07-08T18:39:04Z")
Hi guys, actually I am updating my code to do a proper json file support. I am actually coding a class method to load a class from a json file AND an instance method as well to load value from json file.
The problem is, I don’t know how to implement that properly for the instance method. I am getting always a compilation error.
How can I perform that ?
The code:
```auto
module ISM
class FavouriteGroup
def_clone
include JSON::Serializable
property name : String
property softwares : Array(String)
def initialize(@name = ISM::Default::FavouriteGroup::Name, @softwares = Array(String).new)
end
def self.filePath(name = ISM::Default::FavouriteGroup::Name) : String
return Ism.settings.rootPath+ISM::Default::Path::FavouriteGroupsDirectory+name+".json"
end
def self.generateConfiguration(path = filePath)
file = File.open(path,"w")
self.new.to_json
file.close
end
def self.loadConfiguration(path = filePath)
if !File.exists?(path)
generateConfiguration(path)
end
return from_json(File.read(path))
end
def loadConfiguration(path = self.class.filePath)
if !File.exists?(path)
writeConfiguration(path)
end
self = self.class.from_json(File.read(path))
end
def writeConfiguration(path = self.class.filePath)
file = File.open(path,"w")
to_json(file)
file.close
end
end
end
```
As I expected, we cannot do that:
```auto
self = self.class.from_json(File.read(path))
```
But how can I perform that ?
---
### Author:  [@Blacksmoke16](https://forum.crystal-lang.org/u/Blacksmoke16)
#### Post date: [July 8, 2024, 9:55pm UTC](https://forum.crystal-lang.org/t/change-the-state-of-instancied-class-by-a-method-with-json-file/7003/2 "2024-07-08T21:55:27Z")
To start, it feels a bit wrong to create a new instance, just to save it to a file as part of the `.generateConfiguration` method. Like at that point just do like `FavouriteGroup.new.save` or something. Also it has a bug in that you’re not passing `file` to `#to_json`, so it’s not saving anything.
> [@Fulgurance](#):
>
> I am actually coding a class method to load a class from a json file AND an instance method as well to load value from json file.
What’s actually the use case here? Is there an expectation that the JSON file may be edited outside of this `FavouriteGroup` type causing it to become out of sync or?
---
### Author:  [@Fulgurance](https://forum.crystal-lang.org/u/Fulgurance)
#### Post date: [July 9, 2024, 11:32am UTC](https://forum.crystal-lang.org/t/change-the-state-of-instancied-class-by-a-method-with-json-file/7003/3 "2024-07-09T11:32:31Z")
I will update that. To be honest I don’t know why I done that 😐
Thank you mate