Merge pull request eugenp#6943 from amit2103/BAEL-14320

[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 List<T> findAll() {
     }
 
     @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 List<T> findAll() {
         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>