Yar stands for: Yet Another Registry

This project is a registry implementation based on OSGi service registry. It aims to provide dynamic registry feature as OSGi does. The main difference is on the object / service lifecycle. In OSFi service in registry are instance object except if you are using the ServiceFactory facility. But it is quite complex to have a new instance for each call. There you come quickly with shared mutability. I like the Guice approach and in an enterprise environment I prefer "spend time" on object creation than on thread-safety. This is where this project try to introduce a registry where you can store Guava Supplier (i.e. Jax-inject Provider). By this way it is up to the service provider to decide the lifecycle of its object. This project aims to join Guice object lifecycle and OSGi.

The registry is design around the Id<T> and the Supplier<T> (c.f. guava) where Id defines the Type of the Supplier and optionally a qualifying annotation.

The main driver is the generic type and then the qualifying annotation can be used to refine the filtering. If you provide an Id<T> without annotation then all the Supplier<T> will be returned even if their associated key in the registry are qualifyed with an annotation.

More formally imagine that you have tow DataSource registered in the registry one for the DB1 and the other one for the DB2 using yar-guice capability:

public class DataSourceRegistrationModule extends AbstractRegistryModule {
    public void configureRegistry() {
        register(Key.get(DataSource.class, named("DB1"))).to(DB1DataSource.class);
        register(Key.get(DataSource.class, named("DB2"))).to(DB2DataSource.class);
    }
}

Then following query on the registry will produce:

    public void testRetriveAllDataSourcesByClass(Registry registry) {
        List<DataSource> dataSources = registry.getAll(DataSource.class);
        assertThat(dataSources.size(), is(2));
    }

    public void testRetriveAllDataSourcesId(Registry registry) {
        List<DataSource> dataSources = registry.getAll(GuiceId.of(DataSource.class));
        assertThat(dataSources.size(), is(2));
    }

    public void testRetriveAllDataSourcesIdAndName(Registry registry) {
        List<DataSource> dataSources = registry.getAll(GuiceId.of(DataSource.class, named("DB2")));
        assertThat(dataSources.size(), is(1));
        assertThat(dataSources.get(0)..getClass().<annotations(Named.class)>.value(), is("DB2"));
    }

All modifications to the registry are done by a single thread to simplify the implementation. They are queued by the registry mutation methods and them consumed by the mutation unique thread.

TODO

TODO