Hi, I can't comment on Spring DM, because I don't have any experience there, but if you use blueprint it can be possible if you define the reference to have an optional availability for example:
<?xml version="1.0" encoding="UTF-8"?> <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0";> <bean class="privatepackage.Interface1Impl" init-method="init" id="bean1"> <property name="thing" ref="ref1"></property> </bean> <bean class="privatepackage.Interface2Impl" id="bean2"></bean> <service ref="bean1" interface="publicpackage.Interface1"></service> <service ref="bean2" interface="publicpackage.Interface2"></service> <reference id="ref1" interface="publicpackage.Interface2" availability="optional"> </reference> </blueprint> Having run this through the init method of Interface1Impl has the reference injected by the time it is called, but of course this isn't necessarily safe to assume. I'm going to head back to the blueprint spec to see if this cycle is prohibited from working for a mandatory reference, but if it isn't I'll raise a JIRA to allow this type of cycle. Alasdair On 26 August 2010 16:17, Kirk Knoernschild <[email protected]> wrote: > I've been using Spring DM, and one thing that I'm struggling with is that a > bundle that exports a service is unable to use that service. This seems to be > a feasible design option, and I'm wondering what others have done to work > around it. > > For instance, let's say I have three bundles. > > BundleA with Interface1, Interface2, Interface1Impl, and Interface2Impl1. > BundleB with Interface2Impl2 > BundleC with ClassC that uses Interface1. > > On start, BundleA registers two new services Interface1Service and > Interface2Service, using Interface1Impl and Interface2Impl1 as their > implementations, respectively. As it happens, the Interface1Impl requires an > Interface2 type, so using Spring DM, I've tried injecting the Interface2 > service into the Interface1 service. It doesn't work because Spring DM > doesn't allow a bundle to use a service it registers, so I inject it as a > regular bean. > > I want to do this because I install BundleB and register another > Interface2Service service, now using Interface2Impl2. Because I cannot inject > the service backed by Interface2Impl1 into the service backed by > Interface1Impl, the service backed by Interface1Impl won't be able to use > Interface2Impl2. > > FWIW, I can move Interface2 and Interface2Impl1 to a separate bundle and > register it as a service. That does work, but it's not the application > structure I want. > > Possibly there is an alternative design to this that is more suitable to this > situation. I'm just not sure what that is at this point. Any suggestions are > appreciated. > > I can send code if it would be helpful to illustrate this. > > Kirk Knoernschild > http://www.kirkk.com > http://techdistrict.kirkk.com > http://planet.kirkk.com > twitter: pragkirk > > > > > -- Alasdair Nottingham [email protected]
