FactoryRankTest.java

import java.util.function.Supplier;

import javax.inject.Inject;
import javax.inject.Singleton;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Response;

import org.glassfish.hk2.api.Factory;
import org.glassfish.hk2.utilities.binding.AbstractBinder;
// import org.glassfish.jersey.internal.inject.AbstractBinder;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;

import static org.junit.Assert.assertEquals;

/**
 * https://stackoverflow.com/q/52513611/2587435
 *
 * Reproduces problem for Stack Overflow question. Seems the problem is with Jersey and not HK2.
 * If we use the Jersey `org.glassfish.jersey.internal.inject.AbstractBinder`, when we use
 * `ranked()` with the `bindFactory()`, it does not work. But if we switch over to using the HK2
 * `org.glassfish.hk2.utilities.binding.AbstractBinder` it works.
 *
 * In this test, we are testing that the service either has the message "Test Service" or
 * "Production Service". If the ranking is working correctly, it should show "Test Service" as
 * we want to override the production service during test.
 *
 * The default setup is using the HK2 `AbstractBinder`. To see the Jersey one, comment out the
 * HK2 `AbstractBinder` import and uncomment the Jersey import. Also uncomment the commented out
 * `bindFactory()` in both `AbstractBinders` and comment out the one that is not commented.
 *
 * Two required dependency to run this test.
 *
 * <dependency>
 *     <groupId>org.glassfish.jersey.test-framework.providers</groupId>
 *     <artifactId>jersey-test-framework-provider-grizzly2</artifactId>
 *     <version>2.27</version>
 *     <scope>test</scope>
 * </dependency>
 * <dependency>
 *     <groupId>org.glassfish.jersey.inject</groupId>
 *     <artifactId>jersey-hk2</artifactId>
 *     <version>2.27</version>
 * </dependency>
 *
 */
public class FactoryRankTest extends JerseyTest {

    public static class Service {
        public String msg;
    }

    public static class ProductionServiceSupplier implements Supplier<Service> {

        @Override
        public Service get() {
            Service service = new Service();
            service.msg = "Production Service";
            return service;
        }
    }

    public static class ProductionServiceFactory implements Factory<Service> {

        @Override
        public Service provide() {
            Service service = new Service();
            service.msg = "Production Service";
            return service;
        }

        @Override
        public void dispose(Service service) {

        }
    }

    @Path("test")
    public static class TestResource {
        @Inject
        private Service service;

        @GET
        public String get() {
            return service.msg;
        }
    }

    public static class ProductionConfig extends ResourceConfig {
        public ProductionConfig() {
            register(TestResource.class);
            register(new AbstractBinder() {
                @Override
                protected void configure() {
//                    bindFactory(ProductionServiceSupplier.class)
//                            .to(Service.class)
//                            .in(Singleton.class);

                    bindFactory(ProductionServiceFactory.class)
                            .to(Service.class)
                            .in(Singleton.class);

                }
            });
        }
    }

    public static class TestServiceSupplier implements Supplier<Service> {

        @Override
        public Service get() {
            Service service = new Service();
            service.msg = "Test Service";
            return service;
        }
    }

    public static class TestServiceFactory implements Factory<Service> {

        @Override
        public Service provide() {
            Service service = new Service();
            service.msg = "Test Service";
            return service;
        }

        @Override
        public void dispose(Service service) {

        }
    }

    public static class TestBinder extends AbstractBinder {

        @Override
        protected void configure() {
//            bindFactory(TestServiceSupplier.class)
//                    .to(Service.class)
//                    .in(Singleton.class)
//                    .ranked(1);

            bindFactory(TestServiceFactory.class)
                    .to(Service.class)
                    .in(Singleton.class)
                    .ranked(1);
        }
    }

    @Override
    public ResourceConfig configure() {
        return new ProductionConfig()
                .register(new TestBinder());
    }

    @Test
    public void testIt() {
        Response res = target("test")
                .request()
                .get();
        String result = res.readEntity(String.class);
        System.out.println(result);

        assertEquals("Test Service", result);
    }
}