How to add run mode to specific class in AEM

If you have run mode setup in AEM, then you can check run mode using

SLING API - https://developer.adobe.com/experience-manager/reference-materials/6-5/javadoc/org/apache/sling/settings/SlingSettingsService.html 

@Component
public class MyService {

    @Reference
    private SlingSettingsService slingSettingsService;

    private boolean isPublish() {
        return this.slingSettingsService.getRunModes().contains("publish");
    }
}

AND

If you want to resolve this service only for few run mode then you can use configurationPolicy property, that means this service will only be resolved if runmode specific repository Configurations are available

@Component(
service = CurrenciesMongoWriter.class,
immediate = true,
configurationPolicy = ConfigurationPolicy.REQUIRE)