How to inject instance of my class to another class?

Question

I'm using play framework 2.8.x and I need to inject my config class to another class and I have written my custom module for creating config. My module looks like the following:

public class ConfigModule extends AbstractModule {
    private Config config;

    public ConfigModule(Environment environment, Config config) {
        this.config = config;
    }

    @Override
    protected void configure() {
        bindRedisConfig();
    }

    void bindRedisConfig() {
        System.out.println("LOAD");
        RedisConfig redisConfig = new RedisConfig(
                config.getString("configuration.redis.host")
                , config.getInt("configuration.redis.port")
                , config.getString("configuration.redis.password")
                , config.getString("configuration.redis.domain")
        );
        bind(RedisConfig.class).annotatedWith(Names.named(Constant.CONFIG_REDIS)).toInstance(redisConfig);
    }
}

and I try to inject it like this:

public class ProcessDataStore {
    private final JedisPool jedisPool;
    private final RedisConfig config;

    @Inject
    public ProcessDataStore(RedisConfig config) {
        this.config = config;
    }
}

my config class is very simple:

@Singleton
public class RedisConfig {
    public final String host;
    public final int port;
    public final String password;
    public final String domain;

    public RedisConfig(String host, int port, String password, String domain) {
        this.host = host;
        this.port = port;
        this.password = password;
        this.domain = domain;
    }
}

but when I run my application I get an exception:

1) Could not find a suitable constructor in config.RedisConfig. Classes must have either one (and only one) constructor annotated with @Inject or a zero-argument constructor that is not private.
  at config.RedisConfig.class(RedisConfig.java:17)
  while locating config.RedisConfig
    for the 1st parameter of repository.ProcessDataStore.<init>(ProcessDataStore.java:25)
  while locating repository.ProcessDataStore
    for field at controllers.DashboardController.db(DashboardController.java:19)
  while locating controllers.DashboardController
    for the 5th parameter of router.Routes.<init>(Routes.scala:38)
  at play.api.inject.RoutesProvider$.bindingsFromConfiguration(BuiltinModule.scala:137):
Binding(class router.Routes to self) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon$4)

if I create default constructor without params my application not thrown any exception but injected RedisConfig is empty. I load my module to the my app:

play.modules.enabled += "modules.ConfigModule"

what can I do wrong?

Answer 1

I see 2 suspicious things.

1) @Singleton annotation on RedisConfig class. It can make injector to create and inject new instance of RedisConfig class instead of redisConfig.

2) Binding definition contains .annotatedWith(Names.named(Constant.CONFIG_REDIS)). Therefore parameter of contructor of ProcessDataStore shoudl be annotated with @Named:

 @Inject
 public ProcessDataStore( @Named(Constant.CONFIG_REDIS) RedisConfig config) {...}