How to write a spring bean with a constructor that contains a list?

Question

I have a list as follows:

ArrayList<DiameterMessageHandler> handlers = new ArrayList<>();
handlers.add(new AARHandler());
handlers.add(new CERHandler());
handlers.add(new PPAHandler());
handlers.add(new STRHandler());
handlers.add(new DWRHandler());

I am wondering how to create a spring bean that takes handlers as one of its arguments, ie is it possible to do this in the applicationContext.xml - Do I have to create separate beans for the list and each of the handlers(AARHandler etc) first? Here is my applicationContext.xml

<bean id="DiameterClient" class="com.rory.ptspsim.diameterclient.DiameterClient" scope="singleton" init-method="start">
        <constructor-arg type="java.lang.String" index="0"><value>${pcca.host}</value></constructor-arg>      
        <constructor-arg index="1">WHAT GOES HERE?</constructor-arg>        
    </bean>

Answer 1

Probably you want all these handlers be Spring beans too. This is the configuration:

<bean id="DiameterClient" class="com.rory.ptspsim.diameterclient.DiameterClient" init-method="start">
    <constructor-arg value="${pcca.host}" />
    <constructor-arg>
        <list>
            <ref bean="aarHandler" />
            ...
        </list>
    </constructor-arg>      
</bean>

<bean id="aarHandler" class="com.rory.ptspsim.diameterclient.AARHandler" />

Answer 2

I think the most appropriate way to do that is:

<bean id="DiameterClient" class="com.rory.ptspsim.diameterclient.DiameterClient"       scope="singleton" init-method="start">
    <constructor-arg type="java.lang.String" index="0"><value>${pcca.host}</value></constructor-arg>
    <constructor-arg index="1">
       <list>
           <ref bean="aarHandler" />
           <ref bean="cerHandler" />     
           <ref bean="ppaHandler" />
           <ref bean="strHandler" />
           <ref bean="dwrHandler" />
       </list>       
    </constructor>
</bean>

you can visit the following link http://springindepth.com/book/index.html

Answer 3

If you want all available Handlers, Spring will also collect them for you via Autowiring:

public DiameterClient(@Autowired List<DiameterMessageHandler> handlers){
    this.handlers = handlers;
}

Now Spring will inject a List of all available Handlers.

See Spring Reference 4.9.2: @Autowired

Answer 4

<bean id="DiameterClient" class="com.rory.ptspsim.diameterclient.DiameterClient" scope="singleton" init-method="start">
    <constructor-arg type="java.lang.String" index="0"><value>${pcca.host}</value></constructor-arg>      
    <constructor-arg index="1">
      <list>
       <bean class="AARHandler"/>
       <bean class="CERHandler"/>
      </list>
    </constructor-arg>        
</bean>

Answer 5

  <list> <ref bean="handler1" /> <ref bean="handler2" /> <ref bean="handler3" /> <ref bean="handler4" /> <ref bean="handler5" /> </list> <bean id="handler1" class="AARHandler"/> <bean id="handler2" class="CERHandler"/> <bean id="handler3" class="PPAHandler"/> <bean id="handler4" class="STRHandler"/> <bean id="handler5" class="DWRHandler"/>