Nesting Configurations

Coat allows embedding config objects in other config objects.

It is helpful in the case when parts of a configuration are reused in multiple other configurations without having to duplicate all the accessor methods of the embedded config class.

Example

As an example see the following MqttConfig that is embedded in the main AppConfig.

 1@Coat.Config
 2public interface MqttConfig {
 3
 4  @Coat.Param(key = "client_id")
 5  public Optional<String>   clientId();
 6
 7  @Coat.Param(key = "broker_address")
 8  public InetAddress        brokerAddress();
 9
10  @Coat.Param(key = "port", defaultValue = "1883")
11  public int port();

1@Coat.Config
2public interface AppConfig {
3
4  @Coat.Param(key = "name")
5  public String name();
6
7  @Coat.Embedded(key = "mqtt")
8  public MqttConfig mqtt();

A config file for that configuration would look like this:

1name                = …
2mqtt.client_id      = …
3mqtt.broker_address = …
4mqtt.port           = …

The config keys of the embedded config get a common prefix that is specified on the @Coat.Embedded annotation of its accessor method. By default that prefix is separated from the actual config key via a single dot.