apollo-client: bind config to java object

[Anilople]

In spring boot, we can bind config to java object by @ConfigurationProperties,

for example

@Configuration
@ConfigurationProperties(prefix = "mail")
public class ConfigProperties {
    
    private String hostName;
    private int port;
    private String from;

    // standard getters and setters
}

will bind properties

#Simple properties
mail.hostname[email protected]
mail.port=9000
mail.from[email protected]

to class ConfigProperties's instance.

If we design some annotation about it, let user can use feature like

• bind properties to a java object or interface's getter method
• add config change listener to observe java object's field
• running without spring, i.e raw jdk can use it too after use apollo-client

Is it will improve user's experience?

reference https://www.baeldung.com/configuration-properties-in-spring-boot

[nobodyiam]

Generally speaking, adding a custom annotation to support the object binding will enhance the developer experience for non-spring-boot situations. However, I'm not sure whether this is a strong feature as spring boot is used widely now.
BTW, what does add config change listener to observe java object's field mean? I suppose the object binding will invoke setter methods when some config changes?

[Anilople]

object binding will invoke setter methods when some config changes?

Yes.

maybe

@ConfigBind(prefix = "my.datasource")
public class Datasource {
  public void setUrl(String url) {
    // invoke when my.datasource.url is changed
  }
}

or

@ConfigBind(prefix = "my.datasource")
public class Datasource {
  @ConfigChangeInvokeMethod("myMethod")
  private String url;
  public void myMethod(ConfigEvent e) {
    // invoke when my.datasource.url is changed
  }
}

or

@ConfigBind(prefix = "my.datasource")
public class Datasource {
  private String url;
  @InvokeAfterFieldChanged(fieldName = "url")
  public void myMethod(ConfigEvent e) {
    // invoke when my.datasource.url is changed
  }
}

[nobodyiam]

Thanks for the explanation.
Now the only issue is whether this is a strong feature or not.