Autowire reference beans into list by type

Question

I have one class that has a list of objects of Daemon type.

class Xyz {         List<Daemon> daemons; } 

My spring configuration looks like this.

<bean id="xyz" class="package1.Xyz">    <property name="daemons" ref="daemonsList"> </bean>  <bean id="daemon1" class="package1.DaemonImpl1"/> <bean id="daemon2" class="package1.DaemonImpl2"/>  <bean id="daemonsList" class="java.util.ArrayList">         <constructor-arg>             <list>                 <ref bean="daemon1" />                       <ref bean="daemon2" />             </list>         </constructor-arg> </bean> 

Now instead of explicitly wiring each daemon implementation in list, is it possible to autowire all beans of type Daemon automatically in list. Problem I am trying to solve is, If someone creates a bean of new implementation of Daemon class and forgets to wire it into list.

I have seen this question somewhere on stackoverflow but not able to find that again. Apologies for it.

Answer 1

It should work like this (remove the ArrayList bean from your XML):

public Class Xyz {          private List<Daemon> daemons;      @Autowired     public void setDaemons(List<Daemon> daemons){         this.daemons = daemons;     }  } 

I don't think there's a way to do this in XML.

---

See: 3.9.2. @Autowired and @Inject:

It is also possible to provide all beans of a particular type from the ApplicationContext by adding the annotation to a field or method that expects an array of that type:

public class MovieRecommender {    @Autowired   private MovieCatalog[] movieCatalogs;    // ... } 

The same applies for typed collections:

public class MovieRecommender {    private Set<MovieCatalog> movieCatalogs;    @Autowired   // or if you don't want a setter, annotate the field   public void setMovieCatalogs(Set<MovieCatalog> movieCatalogs) {       this.movieCatalogs = movieCatalogs;   }    // ... } 

BTW, as of Spring 4.x, these lists can be ordered automatically using the @Ordered mechanism.