SnakeYAML Dump nested key

Question

I am using SnakeYAML as my YAML parser for a project, and I don't know how to set keys that are nested. For instance, here is a YAML file with nested keys in it.

control:
  advertising:
    enabled: true
logging:
  chat: true
  commands: true
  format: '%id% %date% %username% | %value%'

My goal is to be able to easily set the path control.advertising.enabled or any other path to any value.

When I use

void Set(String key, Object value, String configName){
    Yaml yaml = new Yaml();
    OutputStream oS;
    try {
        oS = new FileOutputStream(main.getDataFolder() + File.separator + configName);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
        return;
    }
    Map<String, Object> data = new HashMap<String, Object>();
    // set data based on original + modified
    data.put(key, value);
    String output = yaml.dump(data);

    try {
        oS.write(output.getBytes());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

to set the value, instead of getting

logging:
  chat: true
  commands: true
  format: '%id% %date% %username% | %value%'

the entire yaml file is cleared and I only get {logging.chat: false}

Thank you!

Answer 1

Define your structure with Java classes:

public class Config {
    public static class Advertising {
        public boolean enabled;
    }
    public static class Control {
        public Advertising advertising;
    }
    public static class Logging {
        public boolean chat;
        public boolean commands;
        public String format;
    }

    Control control;
    Logging logging;
}

Then you can modify it like this:

Yaml yaml = new Yaml();
Config config = yaml.loadAs(inputStream, Config.class);
config.control.advertising.enabled = false;
String output = yaml.dump(config);

Note that loading & saving YAML data this way might mess with the order of mapping keys, because this order is not preserved. I assume that the output order will be according to the field order in the Java classes, but I'm not sure.