import java.util.concurrent.CountDownLatch;

import org.junit.Test;

import com.google.inject.AbstractModule;
import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Singleton;

public class GuiceCircularDependenciesIT extends AbstractModule {

    static interface Store {
        void sell();
    }
    
    static interface Customer {
        void buy();
    }
    
    static class StoreImpl implements Store {
        private final Customer customer;

        @Inject public StoreImpl(Customer customer) {
            this.customer = customer;
        }

        @Override
        public void sell() { }
    }

    static class CustomerImpl implements Customer {

        private Store store;

        @Inject public CustomerImpl(Store store) {
            this.store = store;
        }
        
        @Override
        public void buy() {
            store.sell();
        }
    }
    
    @Override
    protected void configure() {
        bind(Store.class).to(StoreImpl.class);
        bind(Customer.class).to(CustomerImpl.class).in(Singleton.class);
    }
    
    @Test
    public void testCircularDependencies() {
        for (int j = 0; j < 100; ++j) {
            Injector injector = Guice.createInjector(this);
            CountDownLatch latch = new CountDownLatch(8);
            for (int i = 0; i < 8; ++i) {
                Thread thread = new Thread(() -> {
                    try {
                        Customer instance = injector.getInstance(Customer.class);
                        instance.buy();
                    } catch (Exception e) {
                        System.out.println(e);
                    } finally {
                        latch.countDown();
                    }
                });
                thread.setDaemon(true);
                thread.start();
            }
            try {
                latch.await();
                System.out.println("DONE: " + j);
            } catch (InterruptedException e) {
            }
        }

    }
}