#2399 Add OSGi Declarative Services as Component Model

[ktor]

It is work in progress. I've created the pull request to collaborate on the code. It is missing tests but otherwise generates OSGi DS annotations correctly, at least for my use case.

I have a trouble creating OSGi container in the test so it could check if references are properly binded as it is done for Spring Component Model implementation. Maybe it is too much trouble anyways and there is a better / simpler way to test if it is correctly generated. Please advise.

Example of usage

Factory

@Component(immediate = true, property = {}, service = CompanyMapperFactory.class)
public class CompanyMapperFactory {

    @Reference
    private CustomerCompanyLocalService CustomerCompanyLocalService;

    public CustomerCompany createDbCustomerCompany() {
        return CustomerCompanyLocalService.createCustomerCompany(DEFAULT_ID_WILL_BE_IGNORED);
    }

Mapper

@Mapper(componentModel = "osgi_ds", uses = {CompanyMapperFactory.class})
public interface CompanyMapper {

    CustomerCompany map(Company company);

MapperImpl

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2020-12-30T11:14:32+0000",
    comments = "version: 1.4.0.Beta4-SNAPSHOT, compiler: IncrementalProcessingEnvironment from gradle-language-java-5.6.4.jar, environment: Java 1.8.0_272 (Oracle Corporation)"
)
@Component
public class CompanyMapperImpl implements CompanyMapper {

    @Reference
    private CompanyMapperFactory companyMapperFactory;

    @Override
    public CustomerCompany map(Company company) {
        if ( company == null ) {
            return null;
        }

        CustomerCompany customerCompany = companyMapperFactory.createCustomerCompany();

[filiphr]

Thanks for the PR @ktor. I have extremely limited knowledge with OSGi, so I would trust your judgement here.

I've left some comments, which I think need addressing.

I have a trouble creating OSGi container in the test so it could check if references are properly binded as it is done for Spring Component Model implementation. Maybe it is too much trouble anyways and there is a better / simpler way to test if it is correctly generated. Please advise.

Before merging this we should have tests for this. Otherwise, we won't be able to maintain this. I don't know what kind of troubles you had. I guess it is something with our custom test harness and our custom class loaders. I would suggest checking CompilingStatement, most likely you'll need to add the reference to the jar in the same way it is done for spring-beans.

[ktor]

Thank you for code review @filiphr. I've made the changes you've proposed and added simple test to confirm that generated mappers contain required annotations.

So far I had no luck with integration test where junit would invoke simple osgi container that would confirm that components are initialized and bind correctly but the DS annotations are pretty simple.

I believe the simple test could suffice if maintained: would only change once OSGi DS specification changes (very rare).

[ktor]

Changed to draft because after changes in OsgiDsComponentProcessor my DS supplied factory that is references in uses attribute of @Mapper annotation does not get needed @Reference annotation. I will update the test for the usecase.

[filiphr]

I believe the simple test could suffice if maintained: would only change once OSGi DS specification changes (very rare).

Can you please show me an example test case that I can look into, to see why it isn't working in our test setup. We do have some complex setup of course 😄

[ktor]

Can you please show me an example test case that I can look into

Hi @filiphr, I've finished the "simple" tests, meaning I've copied all the tests from spring decorator and injection strategy to osgi_ds packages and adjusted the "simple" tests to checkup on expected, generated OSGi DS result.

All places that I've failed to test are now commented with TODO osgi. Those are methods like osgiUp, osgiDown and test methods that require some kind of osgi runtime or mock suite. Those methods should be responsible for spinning up a local osgi container in junit test runtime or to run some kind of osgi mocks. Tried following without success:

1. https://bnd.bndtools.org/chapters/315-launchpad-testing.html and failed to provide "remote workspace" for it to use
2. https://sling.apache.org/documentation/development/osgi-mock.html failed to apply completely, it was some time ago and don't remember exactly what was not working, maybe I'll give it another chance

[ktor]

Hello @cschneider,

Thank you for your presentation: https://www.youtube.com/watch?v=9WGbnfa2BaM. I write to you in hope that you could help me to implement OSGi DS test for services generated with mapstruct mapper generator.

I would be very grateful if you could take a look at one particular test: https://github.com/mapstruct/mapstruct/pull/2400/files#diff-54dfa14bd76fc710acc684c990077482d0fc184f6b440d4e5b05b1d8d22666ccR56 and suggest a way to test if OSGi DS annotations generated with the mapstruct tooling would work in osgi container supporting OSGi R7.

Classes generated with mvn clean test that should somehow be included in the test and activated with the osgi runtime / test suite are prepared in the directory processor/target/compilation-tests/org.mapstruct.ap.test.decorator.osgi_ds.constructor.OsgiDsDecoratorTest/{{name_of_a_test_method}}_eclipse/classes

Thank you!