[BAEL-14320] - Moved code for Intro to Spring Data JPA Article

persistence-modules/spring-persistence-simple/README.md

@@ -9,6 +9,7 @@
 - [The DAO with Spring and Hibernate](http://www.baeldung.com/persistence-layer-with-spring-and-hibernate)
 - [DAO with Spring and Generics](https://www.baeldung.com/simplifying-the-data-access-layer-with-spring-and-java-generics)
 - [Transactions with Spring and JPA](https://www.baeldung.com/transaction-configuration-with-jpa-and-spring)
+- [Introduction to Spring Data JPA](http://www.baeldung.com/the-persistence-layer-with-spring-data-jpa)
 
 
 ### Eclipse Config 

persistence-modules/spring-persistence-simple/src/main/java/com/baeldung/persistence/dao/common/AbstractHibernateDao.java

@@ -28,9 +28,10 @@ public abstract class AbstractHibernateDao<T extends Serializable> extends Abstr
     }
 
     @Override
-    public void create(final T entity) {
+    public T create(final T entity) {
         Preconditions.checkNotNull(entity);
         getCurrentSession().saveOrUpdate(entity);
+        return entity;
     }
 
     @Override

persistence-modules/spring-persistence-simple/src/main/java/com/baeldung/persistence/dao/common/IOperations.java

@@ -9,7 +9,7 @@ public interface IOperations<T extends Serializable> {
 
     List<T> findAll();
 
-    void create(final T entity);
+    T create(final T entity);
 
     T update(final T entity);
 

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/persistence/dao/AbstractJpaDAO.java

@@ -26,8 +26,9 @@ public abstract class AbstractJpaDAO<T extends Serializable> {
         return entityManager.createQuery("from " + clazz.getName()).getResultList();
     }
 
-    public void create(final T entity) {
+    public T create(final T entity) {
         entityManager.persist(entity);
+        return entity;
     }
 
     public T update(final T entity) {

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/persistence/dao/IFooDao.java

@@ -10,7 +10,7 @@ public interface IFooDao {
 
     List<Foo> findAll();
 
-    void create(Foo entity);
+    Foo create(Foo entity);
 
     Foo update(Foo entity);
 

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/spring/data/persistence/config/PersistenceConfig.java

@@ -0,0 +1,85 @@
+package org.baeldung.spring.data.persistence.config;
+
+import java.util.Properties;
+
+import javax.sql.DataSource;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.PropertySource;
+import org.springframework.core.env.Environment;
+import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
+import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.jdbc.datasource.DriverManagerDataSource;
+import org.springframework.orm.jpa.JpaTransactionManager;
+import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
+import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+import com.google.common.base.Preconditions;
+
+@Configuration
+@EnableTransactionManagement
+@PropertySource({ "classpath:persistence-${envTarget:h2}.properties" })
+@ComponentScan({ "org.baeldung.spring.data.persistence" })
+// @ImportResource("classpath*:springDataPersistenceConfig.xml")
+@EnableJpaRepositories(basePackages = "org.baeldung.spring.data.persistence.dao")
+public class PersistenceConfig {
+
+    @Autowired
+    private Environment env;
+
+    public PersistenceConfig() {
+        super();
+    }
+
+    @Bean
+    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
+        final LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
+        em.setDataSource(dataSource());
+        em.setPackagesToScan(new String[] { "org.baeldung.spring.data.persistence.model" });
+
+        final HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
+        // vendorAdapter.set
+        em.setJpaVendorAdapter(vendorAdapter);
+        em.setJpaProperties(additionalProperties());
+
+        return em;
+    }
+
+    @Bean
+    public DataSource dataSource() {
+        final DriverManagerDataSource dataSource = new DriverManagerDataSource();
+        dataSource.setDriverClassName(Preconditions.checkNotNull(env.getProperty("jdbc.driverClassName")));
+        dataSource.setUrl(Preconditions.checkNotNull(env.getProperty("jdbc.url")));
+        dataSource.setUsername(Preconditions.checkNotNull(env.getProperty("jdbc.user")));
+        dataSource.setPassword(Preconditions.checkNotNull(env.getProperty("jdbc.pass")));
+
+        return dataSource;
+    }
+
+    @Bean
+    public PlatformTransactionManager transactionManager() {
+        final JpaTransactionManager transactionManager = new JpaTransactionManager();
+        transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
+
+        return transactionManager;
+    }
+
+    @Bean
+    public PersistenceExceptionTranslationPostProcessor exceptionTranslation() {
+        return new PersistenceExceptionTranslationPostProcessor();
+    }
+
+    final Properties additionalProperties() {
+        final Properties hibernateProperties = new Properties();
+        hibernateProperties.setProperty("hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto"));
+        hibernateProperties.setProperty("hibernate.dialect", env.getProperty("hibernate.dialect"));
+        // hibernateProperties.setProperty("hibernate.globally_quoted_identifiers", "true");
+        return hibernateProperties;
+    }
+
+}

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/spring/data/persistence/dao/IFooDao.java

@@ -0,0 +1,11 @@
+package org.baeldung.spring.data.persistence.dao;
+
+import org.baeldung.spring.data.persistence.model.Foo;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
+public interface IFooDao extends JpaRepository<Foo, Long> {
+
+    @Query("SELECT f FROM Foo f WHERE LOWER(f.name) = LOWER(:name)")
+    Foo retrieveByName(@Param("name") String name);
+}

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/spring/data/persistence/model/Foo.java

@@ -0,0 +1,83 @@
+package org.baeldung.spring.data.persistence.model;
+
+import java.io.Serializable;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class Foo implements Serializable {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private long id;
+
+    @Column(nullable = false)
+    private String name;
+
+    public Foo() {
+        super();
+    }
+
+    public Foo(final String name) {
+        super();
+
+        this.name = name;
+    }
+
+    // API
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(final long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(final String name) {
+        this.name = name;
+    }
+
+    //
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((name == null) ? 0 : name.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(final Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        final Foo other = (Foo) obj;
+        if (name == null) {
+            if (other.name != null)
+                return false;
+        } else if (!name.equals(other.name))
+            return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder builder = new StringBuilder();
+        builder.append("Foo [name=").append(name).append("]");
+        return builder.toString();
+    }
+
+}

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/spring/data/persistence/service/IFooService.java

@@ -0,0 +1,11 @@
+package org.baeldung.spring.data.persistence.service;
+
+import org.baeldung.spring.data.persistence.model.Foo;
+
+import com.baeldung.persistence.dao.common.IOperations;
+
+public interface IFooService extends IOperations<Foo> {
+
+    Foo retrieveByName(String name);
+
+}

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/spring/data/persistence/service/common/AbstractService.java

@@ -0,0 +1,56 @@
+package org.baeldung.spring.data.persistence.service.common;
+
+import java.io.Serializable;
+import java.util.List;
+
+import org.springframework.data.repository.PagingAndSortingRepository;
+import org.springframework.transaction.annotation.Transactional;
+
+import com.baeldung.persistence.dao.common.IOperations;
+import com.google.common.collect.Lists;
+
+@Transactional
+public abstract class AbstractService<T extends Serializable> implements IOperations<T> {
+
+    // read - one
+
+    @Override
+    @Transactional(readOnly = true)
+    public T findOne(final long id) {
+        return getDao().findById(id).orElse(null);
+    }
+
+    // read - all
+
+    @Override
+    @Transactional(readOnly = true)
+    public List<T> findAll() {
+        return Lists.newArrayList(getDao().findAll());
+    }
+
+    // write
+
+    @Override
+    public T create(final T entity) {
+        return getDao().save(entity);
+    }
+
+    @Override
+    public T update(final T entity) {
+        return getDao().save(entity);
+    }
+    
+    @Override
+    public void delete(T entity) {
+        getDao().delete(entity);
+    }
+    
+    @Override
+    public void deleteById(long entityId) {
+        T entity = findOne(entityId);
+        delete(entity);
+    }
+
+    protected abstract PagingAndSortingRepository<T, Long> getDao();
+
+}

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/spring/data/persistence/service/impl/FooService.java

@@ -0,0 +1,38 @@
+package org.baeldung.spring.data.persistence.service.impl;
+
+
+import org.baeldung.spring.data.persistence.model.Foo;
+import org.baeldung.spring.data.persistence.dao.IFooDao;
+import org.baeldung.spring.data.persistence.service.IFooService;
+import org.baeldung.spring.data.persistence.service.common.AbstractService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.repository.PagingAndSortingRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Service
+@Transactional
+public class FooService extends AbstractService<Foo> implements IFooService {
+
+    @Autowired
+    private IFooDao dao;
+
+    public FooService() {
+        super();
+    }
+
+    // API
+
+    @Override
+    protected PagingAndSortingRepository<Foo, Long> getDao() {
+        return dao;
+    }
+
+    // custom methods
+
+    @Override
+    public Foo retrieveByName(final String name) {
+        return dao.retrieveByName(name);
+    }
+
+}

persistence-modules/spring-persistence-simple/src/main/java/org/baeldung/util/IDUtil.java

@@ -0,0 +1,33 @@
+package org.baeldung.util;
+
+import java.util.Random;
+
+public final class IDUtil {
+
+    private IDUtil() {
+        throw new AssertionError();
+    }
+
+    // API
+
+    public static String randomPositiveLongAsString() {
+        return Long.toString(randomPositiveLong());
+    }
+
+    public static String randomNegativeLongAsString() {
+        return Long.toString(randomNegativeLong());
+    }
+
+    public static long randomPositiveLong() {
+        long id = new Random().nextLong() * 10000;
+        id = (id < 0) ? (-1 * id) : id;
+        return id;
+    }
+
+    private static long randomNegativeLong() {
+        long id = new Random().nextLong() * 10000;
+        id = (id > 0) ? (-1 * id) : id;
+        return id;
+    }
+
+}

persistence-modules/spring-persistence-simple/src/main/resources/springDataPersistenceConfig.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jpa="http://www.springframework.org/schema/data/jpa"
+    xsi:schemaLocation="
+    http://www.springframework.org/schema/beans 
+    http://www.springframework.org/schema/beans/spring-beans.xsd
+    http://www.springframework.org/schema/data/jpa 
+    http://www.springframework.org/schema/data/jpa/spring-jpa.xsd"
+>
+
+    <jpa:repositories base-package="org.baeldung.persistence.dao"/>
+
+</beans>

persistence-modules/spring-persistence-simple/src/test/java/org/baeldung/spring/data/persistence/service/AbstractServicePersistenceIntegrationTest.java

@@ -0,0 +1,256 @@
+package org.baeldung.spring.data.persistence.service;
+
+import static org.apache.commons.lang3.RandomStringUtils.randomAlphabetic;
+import static org.hamcrest.Matchers.hasItem;
+import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThat;
+
+import java.io.Serializable;
+import java.util.List;
+
+import org.baeldung.spring.data.persistence.model.Foo;
+import org.baeldung.util.IDUtil;
+import org.hamcrest.Matchers;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.springframework.dao.DataAccessException;
+
+import com.baeldung.persistence.dao.common.IOperations;
+
+public abstract class AbstractServicePersistenceIntegrationTest<T extends Serializable> {
+
+    // tests
+
+    // find - one
+
+    @Test
+    /**/public final void givenResourceDoesNotExist_whenResourceIsRetrieved_thenNoResourceIsReceived() {
+        // When
+        final Foo createdResource = getApi().findOne(IDUtil.randomPositiveLong());
+
+        // Then
+        assertNull(createdResource);
+    }
+
+    @Test
+    public void givenResourceExists_whenResourceIsRetrieved_thenNoExceptions() {
+        final Foo existingResource = persistNewEntity();
+        getApi().findOne(existingResource.getId());
+    }
+
+    @Test
+    public void givenResourceDoesNotExist_whenResourceIsRetrieved_thenNoExceptions() {
+        getApi().findOne(IDUtil.randomPositiveLong());
+    }
+
+    @Test
+    public void givenResourceExists_whenResourceIsRetrieved_thenTheResultIsNotNull() {
+        final Foo existingResource = persistNewEntity();
+        final Foo retrievedResource = getApi().findOne(existingResource.getId());
+        assertNotNull(retrievedResource);
+    }
+
+    @Test
+    public void givenResourceExists_whenResourceIsRetrieved_thenResourceIsRetrievedCorrectly() {
+        final Foo existingResource = persistNewEntity();
+        final Foo retrievedResource = getApi().findOne(existingResource.getId());
+        assertEquals(existingResource, retrievedResource);
+    }
+
+    // find - one - by name
+
+    // find - all
+
+    @Test
+    /**/public void whenAllResourcesAreRetrieved_thenNoExceptions() {
+        getApi().findAll();
+    }
+
+    @Test
+    /**/public void whenAllResourcesAreRetrieved_thenTheResultIsNotNull() {
+        final List<Foo> resources = getApi().findAll();
+
+        assertNotNull(resources);
+    }
+
+    @Test
+    /**/public void givenAtLeastOneResourceExists_whenAllResourcesAreRetrieved_thenRetrievedResourcesAreNotEmpty() {
+        persistNewEntity();
+
+        // When
+        final List<Foo> allResources = getApi().findAll();
+
+        // Then
+        assertThat(allResources, not(Matchers.<Foo> empty()));
+    }
+
+    @Test
+    /**/public void givenAnResourceExists_whenAllResourcesAreRetrieved_thenTheExistingResourceIsIndeedAmongThem() {
+        final Foo existingResource = persistNewEntity();
+
+        final List<Foo> resources = getApi().findAll();
+
+        assertThat(resources, hasItem(existingResource));
+    }
+
+    @Test
+    /**/public void whenAllResourcesAreRetrieved_thenResourcesHaveIds() {
+        persistNewEntity();
+
+        // When
+        final List<Foo> allResources = getApi().findAll();
+
+        // Then
+        for (final Foo resource : allResources) {
+            assertNotNull(resource.getId());
+        }
+    }
+
+    // create
+
+    @Test(expected = RuntimeException.class)
+    /**/public void whenNullResourceIsCreated_thenException() {
+        getApi().create(null);
+    }
+
+    @Test
+    /**/public void whenResourceIsCreated_thenNoExceptions() {
+        persistNewEntity();
+    }
+
+    @Test
+    /**/public void whenResourceIsCreated_thenResourceIsRetrievable() {
+        final Foo existingResource = persistNewEntity();
+
+        assertNotNull(getApi().findOne(existingResource.getId()));
+    }
+
+    @Test
+    /**/public void whenResourceIsCreated_thenSavedResourceIsEqualToOriginalResource() {
+        final Foo originalResource = createNewEntity();
+        final Foo savedResource = getApi().create(originalResource);
+
+        assertEquals(originalResource, savedResource);
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void whenResourceWithFailedConstraintsIsCreated_thenException() {
+        final Foo invalidResource = createNewEntity();
+        invalidate(invalidResource);
+
+        getApi().create(invalidResource);
+    }
+
+    /**
+     * -- specific to the persistence engine
+     */
+    @Test(expected = DataAccessException.class)
+    @Ignore("Hibernate simply ignores the id silently and still saved (tracking this)")
+    public void whenResourceWithIdIsCreated_thenDataAccessException() {
+        final Foo resourceWithId = createNewEntity();
+        resourceWithId.setId(IDUtil.randomPositiveLong());
+
+        getApi().create(resourceWithId);
+    }
+
+    // update
+
+    @Test(expected = RuntimeException.class)
+    /**/public void whenNullResourceIsUpdated_thenException() {
+        getApi().update(null);
+    }
+
+    @Test
+    /**/public void givenResourceExists_whenResourceIsUpdated_thenNoExceptions() {
+        // Given
+        final Foo existingResource = persistNewEntity();
+
+        // When
+        getApi().update(existingResource);
+    }
+
+    /**
+     * - can also be the ConstraintViolationException which now occurs on the update operation will not be translated; as a consequence, it will be a TransactionSystemException
+     */
+    @Test(expected = RuntimeException.class)
+    public void whenResourceIsUpdatedWithFailedConstraints_thenException() {
+        final Foo existingResource = persistNewEntity();
+        invalidate(existingResource);
+
+        getApi().update(existingResource);
+    }
+
+    @Test
+    /**/public void givenResourceExists_whenResourceIsUpdated_thenUpdatesArePersisted() {
+        // Given
+        final Foo existingResource = persistNewEntity();
+
+        // When
+        change(existingResource);
+        getApi().update(existingResource);
+
+        final Foo updatedResource = getApi().findOne(existingResource.getId());
+
+        // Then
+        assertEquals(existingResource, updatedResource);
+    }
+
+    // delete
+
+    // @Test(expected = RuntimeException.class)
+    // public void givenResourceDoesNotExists_whenResourceIsDeleted_thenException() {
+    // // When
+    // getApi().delete(IDUtil.randomPositiveLong());
+    // }
+    //
+    // @Test(expected = RuntimeException.class)
+    // public void whenResourceIsDeletedByNegativeId_thenException() {
+    // // When
+    // getApi().delete(IDUtil.randomNegativeLong());
+    // }
+    //
+    // @Test
+    // public void givenResourceExists_whenResourceIsDeleted_thenNoExceptions() {
+    // // Given
+    // final Foo existingResource = persistNewEntity();
+    //
+    // // When
+    // getApi().delete(existingResource.getId());
+    // }
+    //
+    // @Test
+    // /**/public final void givenResourceExists_whenResourceIsDeleted_thenResourceNoLongerExists() {
+    // // Given
+    // final Foo existingResource = persistNewEntity();
+    //
+    // // When
+    // getApi().delete(existingResource.getId());
+    //
+    // // Then
+    // assertNull(getApi().findOne(existingResource.getId()));
+    // }
+
+    // template method
+
+    protected Foo createNewEntity() {
+        return new Foo(randomAlphabetic(6));
+    }
+
+    protected abstract IOperations<Foo> getApi();
+
+    private final void invalidate(final Foo entity) {
+        entity.setName(null);
+    }
+
+    private final void change(final Foo entity) {
+        entity.setName(randomAlphabetic(6));
+    }
+
+    protected Foo persistNewEntity() {
+        return getApi().create(createNewEntity());
+    }
+
+}

persistence-modules/spring-persistence-simple/src/test/java/org/baeldung/spring/data/persistence/service/FooServicePersistenceIntegrationTest.java

@@ -0,0 +1,77 @@
+package org.baeldung.spring.data.persistence.service;
+
+import static org.apache.commons.lang3.RandomStringUtils.randomAlphabetic;
+import static org.junit.Assert.assertNotNull;
+
+import org.baeldung.spring.data.persistence.model.Foo;
+import org.baeldung.spring.data.persistence.config.PersistenceConfig;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.dao.DataIntegrityViolationException;
+import org.springframework.dao.InvalidDataAccessApiUsageException;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+
+import com.baeldung.persistence.dao.common.IOperations;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = { PersistenceConfig.class }, loader = AnnotationConfigContextLoader.class)
+public class FooServicePersistenceIntegrationTest extends AbstractServicePersistenceIntegrationTest<Foo> {
+
+    @Autowired
+    private IFooService service;
+
+    // tests
+
+    @Test
+    public final void whenContextIsBootstrapped_thenNoExceptions() {
+        //
+    }
+
+    @Test
+    public final void whenEntityIsCreated_thenNoExceptions() {
+        service.create(new Foo(randomAlphabetic(6)));
+    }
+
+    @Test(expected = DataIntegrityViolationException.class)
+    public final void whenInvalidEntityIsCreated_thenDataException() {
+        service.create(new Foo());
+    }
+
+    @Test(expected = DataIntegrityViolationException.class)
+    public final void whenEntityWithLongNameIsCreated_thenDataException() {
+        service.create(new Foo(randomAlphabetic(2048)));
+    }
+
+    // custom Query method
+
+    @Test
+    public final void givenUsingCustomQuery_whenRetrievingEntity_thenFound() {
+        final String name = randomAlphabetic(6);
+        service.create(new Foo(name));
+
+        final Foo retrievedByName = service.retrieveByName(name);
+        assertNotNull(retrievedByName);
+    }
+
+    // work in progress
+
+    @Test(expected = InvalidDataAccessApiUsageException.class)
+    @Ignore("Right now, persist has saveOrUpdate semantics, so this will no longer fail")
+    public final void whenSameEntityIsCreatedTwice_thenDataException() {
+        final Foo entity = new Foo(randomAlphabetic(8));
+        service.create(entity);
+        service.create(entity);
+    }
+
+    // API
+
+    @Override
+    protected final IOperations<Foo> getApi() {
+        return service;
+    }
+
+}

spring-rest-full/README.md

@@ -9,7 +9,6 @@ The "Learn Spring Security" Classes: http://github.learnspringsecurity.com
 
 ### Relevant Articles: 
 - [Integration Testing with the Maven Cargo plugin](http://www.baeldung.com/integration-testing-with-the-maven-cargo-plugin)
-- [Introduction to Spring Data JPA](http://www.baeldung.com/the-persistence-layer-with-spring-data-jpa)
 - [Project Configuration with Spring](http://www.baeldung.com/project-configuration-with-spring)
 - [Metrics for your Spring REST API](http://www.baeldung.com/spring-rest-api-metrics)
 - [Spring Security Expressions - hasRole Example](https://www.baeldung.com/spring-security-expressions-basic)