java-tutorials/jee-7/src/test/java/com/baeldung/singleton/CarServiceIntegrationTest.java

package com.baeldung.singleton;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;

import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

import javax.ejb.EJB;
import javax.enterprise.context.spi.CreationalContext;
import javax.enterprise.inject.spi.Bean;
import javax.enterprise.inject.spi.BeanManager;
import javax.enterprise.inject.spi.CDI;
import javax.inject.Inject;

import org.jboss.arquillian.container.test.api.Deployment;
import org.jboss.arquillian.junit.Arquillian;
import org.jboss.shrinkwrap.api.ShrinkWrap;
import org.jboss.shrinkwrap.api.asset.EmptyAsset;
import org.jboss.shrinkwrap.api.spec.JavaArchive;
import org.junit.Before;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.MethodSorters;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@RunWith(Arquillian.class)
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class CarServiceIntegrationTest {

    public static final Logger LOG = LoggerFactory.getLogger(CarServiceIntegrationTest.class);

    @Deployment
    public static JavaArchive createDeployment() {
        return ShrinkWrap.create(JavaArchive.class)
            .addClasses(CarServiceBean.class, CarServiceSingleton.class, CarServiceEjbSingleton.class, Car.class)
            .addAsResource("META-INF/persistence.xml")
            .addAsManifestResource(EmptyAsset.INSTANCE, "beans.xml");
    }

    @Inject
    private CarServiceBean carServiceBean;

    @Inject
    private CarServiceSingleton carServiceSingleton;

    @EJB
    private CarServiceEjbSingleton carServiceEjbSingleton;
    
    @Test
    public void givenASingleton_whenGetBeanIsCalledTwice_thenTheSameInstanceIsReturned() {       
        CarServiceSingleton one = getBean(CarServiceSingleton.class);
        CarServiceSingleton two = getBean(CarServiceSingleton.class);
        assertTrue(one == two);
    }
    
    @Test
    public void givenAPojo_whenGetBeanIsCalledTwice_thenDifferentInstancesAreReturned() {       
        CarServiceBean one = getBean(CarServiceBean.class);
        CarServiceBean two = getBean(CarServiceBean.class);
        assertTrue(one != two);
    }

    @SuppressWarnings("unchecked")
    private <T> T getBean(Class<T> beanClass) {
        BeanManager bm = CDI.current().getBeanManager();
        Bean<T> bean = (Bean<T>) bm.getBeans(beanClass).iterator().next();
        CreationalContext<T> ctx = bm.createCreationalContext(bean);
        return (T) bm.getReference(bean, beanClass, ctx);
    }

    @Test
    public void givenCDI_whenConcurrentAccess_thenLockingIsNotProvided() {
        for (int i = 0; i < 10; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    String model = Double.toString(Math.round(Math.random() * 100));
                    Car car = new Car("Speedster", model);
                    int serviceQueue = carServiceSingleton.service(car);
                    assertTrue(serviceQueue < 10);                     
                }
            }).start();
        }
        return;
    }
    
    @Test
    public void givenEJB_whenConcurrentAccess_thenLockingIsProvided() {
        for (int i = 0; i < 10; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    String model = Double.toString(Math.round(Math.random() * 100));
                    Car car = new Car("Speedster", model);
                    int serviceQueue = carServiceEjbSingleton.service(car);
                    assertEquals(0, serviceQueue);
                }
            }).start();
        }
        return;
    }

}