java - Declaring an array of objects in a Spring bean context

Question

I'm trying to create an array of objects in a Spring context file so I can inject it to a constructor that's declared like this:

public RandomGeocodingService(GeocodingService... services) { }

I'm trying to use the <array> tag:

<bean id="googleGeocodingService" class="geocoding.GoogleGeocodingService">
 <constructor-arg ref="proxy" />
 <constructor-arg value="" />
</bean>

<bean id="geocodingService" class="geocoding.RandomGeocodingService">
    <constructor-arg>
        <array value-type="geocoding.GeocodingService">
            <!-- How do I reference the google geocoding service here? -->
        </array>
    </constructor-arg>
</bean>

I haven't been able to find an example or something in the in the documentation on how to do this. Also, you have any suggestions for a better way of acheiving what I'm trying to do, please let me know :).

Answer 1

That's because there's no such thing as <array>, there's only <list>.

The good news is that Spring will auto-convert between lists and arrays as required, so defined your array as a <list>, and Spring will be coerce it into an array for you.

This should work:

<bean id="googleGeocodingService" class="geocoding.GoogleGeocodingService">
   <constructor-arg ref="proxy" />
   <constructor-arg value="" />
</bean>

<bean id="geocodingService" class="geocoding.RandomGeocodingService">
    <constructor-arg>
        <list>
           <ref bean="googleGeocodingService"/>
        </list>
    </constructor-arg>
</bean>

Spring will also coerce a single bean into a list, if required:

<bean id="geocodingService" class="geocoding.RandomGeocodingService">
    <constructor-arg>
       <ref bean="googleGeocodingService"/>
    </constructor-arg>
</bean>