Question

I am a Spring newbie. I found that sometime we need to construct an object using runtime data, but fixed value is used in constructor inject of Spring. I know I could create a setter method and change the value with it, but I don’t think this an elegant solution. Could any one tell me how to do it?

Answer 1

Generally for this my preference is to make a factory like so:

@Service
public class RuntimeObjectFactoryImpl implements RuntimeObjectFactory {
    private final CustomObjectTypeA oA;
    private final CustomObjectTypeB oB;

    @Autowired
    public RuntimeObjectFactoryImpl(final CustomObjectTypeA oA, final CustomObjectTypeB oB) {
        this.oA = oA;
        this.oB = oB;
    }

    @Override
    public RuntimeObject get(CustomObjectTypeC oC) {
        return new RuntimeObject(oA, oB, oC);
    }
}

This can be configured in XML aswell (which I would generally recommend over annotations for wiring business services, but it’s a more presentable answer here to use annotations). So then at runtime:

RuntimeObject o = runtimeObjectFactory.get(new CustomObjectTypeC(...));