Support for custom objects in ListOption

[TechPro424]

Currently, an ArrayList<custom object class> does not seem to work as a valid config entry

For example, if I have a custom class such as

public class CustomObject {
  String a = "abcd"
  ArrayList<String> b = new ArrayList<String>()
}

And the following config entry

@ConfigEntry public ArrayList<CustomObject> customObjects = new ArrayList<CustomObject>();

And a method to add new CustomObjects to the group

public void addNewCustomObjectToConfig(String name, String[] strings1) {

        ArrayList<String> strings2 = new ArrayList<String>();

        for (String string : strings1) {
            strings2.add(player);
        }

        CustomObject newCustomObject = new CustomObject(name, strings2);
        customObjects.add(newCustomObject);
        configInstance.save();

    }

Whenever I use this method in any other part of my code, only an empty object {} gets added to the ArrayList<CustomObject>

Please add support for such custom objects While I have heard that adding support for such custom objects is quite hard, I felt I should at least create an issue so that the requirement is documented here on GitHub.

This issue is based on this support forum post in the Discord server

[isXander]

I assume you are using GsonConfigInstance, which just used GSON, you have access to the GSON builder whilst constructing the instance.

[TechPro424]

Ok, but what can I do with the GSON Builder? Isn't that just used to set options like nice formatting or serializing null values?

[isXander]

You can set type adapters which tell GSON how to serialize certain classes

[TechPro424]

Thanks. that fixed it! For those who have a similar issue, here is my type adapter:

import java.io.IOException;
import java.util.ArrayList;

import com.google.gson.TypeAdapter;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;

public class GroupTypeAdapter extends TypeAdapter<CustomObject> {

    @Override
    public CustomObject read(final JsonReader in) throws IOException {
        CustomObject customObject = new CustomObject("abcd", new ArrayList<String>());

        in.beginObject();
        while(in.hasNext()) {
            switch (in.nextName()) {
                case "a":
                    customObject.a = in.nextString();
                    break;

                case "b":
                    in.beginArray();
                    while(in.hasNext()) {
                        customObject.b.add(in.nextString());
                    }
                    in.endArray();
            }
        }
        in.endObject();
        return customObject;

    }

    @Override
    public void write(final JsonWriter out, final CustomObject customObject) throws IOException {
        out.beginObject();
        out.name("a").value(customObject.a);
        out.name("b").beginArray();
        for (String string : customObject.b) {
            out.value(string);
        }
        out.endArray();
        out.endObject();
    }

}