Question

I am building a spring based application that handles server-side game management for a mobile game app. The stack is Spring/Hibernate/Jersey. I want the clients (mobile) to call a REST API to update/retrieve the game state.

I created a TournamentController class which responsability is to update the tournament state using some business logic. This class is designed to be instanciated every time an operation on a Tournament is required and then thrown away.

public class TournamentController {

    @Autowired
    private TournamentDAO tournamentDAO;

    private final Tournament tournament;

    public TournamentController( Tournament tournament ) {
        this.tournament = tournament;
    }

    public void startTournament() {
        if ( tournament.getState() != TournamentState.SETUP ) {
            throw new TournamentAlreadyStartedException();
        }

        tournament.setState( TournamentState.IN_PROGRESS );

        //... some other logic and calls to other DAOs

        tournamentDAO.save( tournament );
    }

}

I also created a TournamentResource class that is the REST front end for the tournament. It’s responsability is to do some basic validation (user security, …) and exception translation.

@Path( "/tournament" )
@Component
@Scope( "prototype" )
public class TournamentResource {

    private static final Log log = LogFactory.getLog( TournamentResource.class );

    @Autowired
    private TournamentDAO tournamentDAO;

    @GET
    @Path( "{tournamentId}/start" )
    @Produces( MediaType.APPLICATION_JSON )
    @Transactional
    public TournamentDTO startTournament( @PathParam( "tournamentId" ) long tournamentId ) {
        Tournament tournament = tournamentDAO.getTournament( tournamentId, LockMode.PESSIMISTIC_WRITE );
        if ( tournament == null ) {
            throw new WebApplicationException( Status.NOT_FOUND );
        }

        try {
            TournamentController controller = new TournamentController( tournament );
            controller.startTournament();

        } catch ( TournamentAlreadyStartedException e ) {
            log.warn( "Could not start tournament " + tournamentId + " since it is already started." );
            throw new RestException( Status.BAD_REQUEST, "Tournament already started" );
        }

        return DTOConverterUtil.getTournament( tournament );
    }

}

I am using load time weaving with AspectJ. Here is my context:

   <context:annotation-config />

   <!-- Make spring aware ANY pojo with the @Configurable annotation -->
   <context:spring-configured />

   <!-- Scan all classes in com.mdarveau for annotations -->
   <context:component-scan base-package="so.question" />

   <!-- Load Time Weaver -->
   <context:load-time-weaver weaver-class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" aspectj-weaving="on" />

   <!-- DB config -->
   <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
      ...
   </bean>

   <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
      <property name="dataSource" ref="dataSource" />
      <property name="packagesToScan" value="com.mdarveau.fnp.model" />
      <property name="hibernateProperties">
         <value>
            hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
         </value>
      </property>
   </bean>

   <bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
      <property name="sessionFactory" ref="sessionFactory" />
   </bean>

   <!-- enable @Transactional -->
   <tx:annotation-driven transaction-manager="txManager" mode="aspectj" />

My TournamentResource class is a singleton by design and is working well.

My problem is that when it instanciate the TournamentController using new instead of spring, it’s @Autowired attributes does not seems to be wired correctly. I tried to add the @Component annotation on it without success.

Should I make TournamentResource ApplicationContextAware and create the TournamentController through spring?

This must be a fairly common problem. I see a lot of examples where the backend is a singleton but I would like to avoid passing the Tournament to every method call on TournamentController (all then to all private methods in TournamentController).

Answer 1

Since you already have load-time weaving and <context:spring-configured />, you can declare your TournamentController as @Configurable.

It will enable autowiring for instances of TournamentController created with new.