From 8209ec4a1f9b7ed8df436031df8650051e8bfad7 Mon Sep 17 00:00:00 2001 From: enpy Date: Wed, 8 May 2019 16:40:54 +0200 Subject: [PATCH] Difference between CDI and EJB singleton (#6915) * Singleton injection examples and tests added * code and tests implemented --- .../main/java/com/baeldung/singleton/Car.java | 28 ++++ .../baeldung/singleton/CarServiceBean.java | 23 +++ .../singleton/CarServiceEjbSingleton.java | 46 ++++++ .../singleton/CarServiceSingleton.java | 47 ++++++ .../singleton/CarServiceIntegrationTest.java | 142 ++++++++++++++++++ 5 files changed, 286 insertions(+) create mode 100644 jee-7/src/main/java/com/baeldung/singleton/Car.java create mode 100644 jee-7/src/main/java/com/baeldung/singleton/CarServiceBean.java create mode 100644 jee-7/src/main/java/com/baeldung/singleton/CarServiceEjbSingleton.java create mode 100644 jee-7/src/main/java/com/baeldung/singleton/CarServiceSingleton.java create mode 100644 jee-7/src/test/java/com/baeldung/singleton/CarServiceIntegrationTest.java diff --git a/jee-7/src/main/java/com/baeldung/singleton/Car.java b/jee-7/src/main/java/com/baeldung/singleton/Car.java new file mode 100644 index 0000000000..0cf7281294 --- /dev/null +++ b/jee-7/src/main/java/com/baeldung/singleton/Car.java @@ -0,0 +1,28 @@ +package com.baeldung.singleton; + +public class Car { + + private String type; + private String model; + private boolean serviced = false; + + public Car(String type, String model) { + super(); + this.type = type; + this.model = model; + } + + public boolean isServiced () { + return serviced; + } + + public void setServiced(Boolean serviced) { + this.serviced = serviced; + } + + @Override + public String toString() { + return "Car [type=" + type + ", model=" + model + "]"; + } + +} diff --git a/jee-7/src/main/java/com/baeldung/singleton/CarServiceBean.java b/jee-7/src/main/java/com/baeldung/singleton/CarServiceBean.java new file mode 100644 index 0000000000..b824882d5d --- /dev/null +++ b/jee-7/src/main/java/com/baeldung/singleton/CarServiceBean.java @@ -0,0 +1,23 @@ +package com.baeldung.singleton; + +import java.util.UUID; + +import javax.enterprise.context.Dependent; + +import org.springframework.web.context.annotation.RequestScope; + +@RequestScope +public class CarServiceBean { + + private UUID id = UUID.randomUUID(); + + public UUID getId() { + return this.id; + } + + @Override + public String toString() { + return "CarService [id=" + id + "]"; + } + +} diff --git a/jee-7/src/main/java/com/baeldung/singleton/CarServiceEjbSingleton.java b/jee-7/src/main/java/com/baeldung/singleton/CarServiceEjbSingleton.java new file mode 100644 index 0000000000..1bbffdd61e --- /dev/null +++ b/jee-7/src/main/java/com/baeldung/singleton/CarServiceEjbSingleton.java @@ -0,0 +1,46 @@ +package com.baeldung.singleton; + +import java.util.UUID; + +import javax.ejb.Singleton; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +@Singleton +public class CarServiceEjbSingleton { + + private static Logger LOG = LoggerFactory.getLogger(CarServiceEjbSingleton.class); + + private UUID id = UUID.randomUUID(); + + private static int serviceQueue; + + public UUID getId() { + return this.id; + } + + @Override + public String toString() { + return "CarServiceEjbSingleton [id=" + id + "]"; + } + + public int service(Car car) { + serviceQueue++; + LOG.info("Car {} is being serviced @ CarServiceEjbSingleton - serviceQueue: {}", car, serviceQueue); + simulateService(car); + serviceQueue--; + LOG.info("Car service for {} is completed - serviceQueue: {}", car, serviceQueue); + return serviceQueue; + } + + private void simulateService(Car car) { + try { + Thread.sleep(100); + car.setServiced(true); + } catch (InterruptedException e) { + LOG.error("CarServiceEjbSingleton::InterruptedException: {}", e); + } + } + +} diff --git a/jee-7/src/main/java/com/baeldung/singleton/CarServiceSingleton.java b/jee-7/src/main/java/com/baeldung/singleton/CarServiceSingleton.java new file mode 100644 index 0000000000..223d139346 --- /dev/null +++ b/jee-7/src/main/java/com/baeldung/singleton/CarServiceSingleton.java @@ -0,0 +1,47 @@ +package com.baeldung.singleton; + +import java.util.UUID; + +import javax.inject.Singleton; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +@Singleton +public class CarServiceSingleton { + + private static Logger LOG = LoggerFactory.getLogger(CarServiceSingleton.class); + + private UUID id = UUID.randomUUID(); + + private static int serviceQueue; + + public UUID getId() { + return this.id; + } + + @Override + public String toString() { + return "CarServiceSingleton [id=" + id + "]"; + } + + public int service(Car car) { + serviceQueue++; + LOG.info("Car {} is being serviced @ CarServiceSingleton - serviceQueue: {}", car, serviceQueue); + simulateService(car); + serviceQueue--; + LOG.info("Car service for {} is completed - serviceQueue: {}", car, serviceQueue); + return serviceQueue; + + } + + private void simulateService(Car car) { + try { + Thread.sleep(100); + car.setServiced(true); + } catch (InterruptedException e) { + LOG.error("CarServiceSingleton::InterruptedException: {}", e); + } + } + +} diff --git a/jee-7/src/test/java/com/baeldung/singleton/CarServiceIntegrationTest.java b/jee-7/src/test/java/com/baeldung/singleton/CarServiceIntegrationTest.java new file mode 100644 index 0000000000..b828296dca --- /dev/null +++ b/jee-7/src/test/java/com/baeldung/singleton/CarServiceIntegrationTest.java @@ -0,0 +1,142 @@ +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.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; + + private static Map idMap = new HashMap<>(); + + @Before + public void setUp() { + // populate idMap only on first run + if (idMap.isEmpty()) { + LOG.info("setUp::carServiceBean: {}", carServiceBean.getId()); + idMap.put("carServiceBeanId", carServiceBean.getId()); + + LOG.info("setUp::carServiceSingleton: {}", carServiceSingleton.getId()); + idMap.put("carServiceSingletonId", carServiceSingleton.getId()); + + LOG.info("setUp::carServiceEjbSingleton: {}", carServiceEjbSingleton.getId()); + idMap.put("carServiceEjbSingletonId", carServiceEjbSingleton.getId()); + } + } + + @Test + public void givenRun1_whenGetId_thenSingletonIdEqual() { + int testRun = 1; + + assertNotNull(carServiceBean); + assertNotNull(carServiceSingleton); + assertNotNull(carServiceEjbSingleton); + + UUID carServiceBeanId = carServiceBean.getId(); + assertEquals(idMap.get("carServiceBeanId"), carServiceBeanId); + LOG.info("Test run {}::carServiceBeanId: {}", testRun, carServiceBeanId); + + UUID carServiceSingletonId = carServiceSingleton.getId(); + assertEquals(idMap.get("carServiceSingletonId"), carServiceSingletonId); + LOG.info("Test run {}::carServiceSingletonId: {}", testRun, carServiceSingletonId); + + UUID carServiceEjbSingletonId = carServiceEjbSingleton.getId(); + assertEquals(idMap.get("carServiceEjbSingletonId"), carServiceEjbSingletonId); + LOG.info("Test run {}::carServiceEjbSingletonId: {}", testRun, carServiceEjbSingletonId); + } + + @Test + public void givenRun2_whenGetId_thenSingletonIdEqual() { + int testRun = 2; + + assertNotNull(carServiceBean); + assertNotNull(carServiceSingleton); + assertNotNull(carServiceEjbSingleton); + + UUID carServiceBeanId = carServiceBean.getId(); + assertNotEquals(idMap.get("carServiceBeanId"), carServiceBeanId); + LOG.info("Test run {}::carServiceBeanId: {}", testRun, carServiceBeanId); + + UUID carServiceSingletonId = carServiceSingleton.getId(); + assertEquals(idMap.get("carServiceSingletonId"), carServiceSingletonId); + LOG.info("Test run {}::carServiceSingletonId: {}", testRun, carServiceSingletonId); + + UUID carServiceEjbSingletonId = carServiceEjbSingleton.getId(); + assertEquals(idMap.get("carServiceEjbSingletonId"), carServiceEjbSingletonId); + LOG.info("Test run {}::carServiceEjbSingletonId: {}", testRun, carServiceEjbSingletonId); + } + + @Test + public void givenRun3_whenSingleton_thenNoLocking() { + 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 givenRun4_whenEjb_thenLocking() { + 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; + } + +} \ No newline at end of file