Merge branch 'master' into master

core-java-modules/core-java-8/src/test/java/com/baeldung/java8/optional/OptionalChainingUnitTest.java

@@ -101,7 +101,7 @@ private Optional<String> getBye() {
     }
 
     private Optional<String> createOptional(String input) {
-        if (input == null || input == "" || input == "empty") {
+        if (input == null || "".equals(input) || "empty".equals(input)) {
             return Optional.empty();
         }
 

core-kotlin-2/README.md

@@ -6,4 +6,5 @@
 - [Kotlin Scope Functions](https://www.baeldung.com/kotlin-scope-functions)
 - [Kotlin Annotations](https://www.baeldung.com/kotlin-annotations)
 - [Split a List into Parts in Kotlin](https://www.baeldung.com/kotlin-split-list-into-parts)
-- [String Comparison in Kotlin](https://www.baeldung.com/kotlin-string-comparison)
+- [String Comparison in Kotlin](https://www.baeldung.com/kotlin-string-comparison)
+- [Guide to JVM Platform Annotations in Kotlin](https://www.baeldung.com/kotlin-jvm-annotations)

persistence-modules/README.md

@@ -5,7 +5,6 @@
 ### Relevant Articles:
 
 - [Introduction to Hibernate Search](http://www.baeldung.com/hibernate-search)
-- [Bootstrapping Hibernate 5 with Spring](http://www.baeldung.com/hibernate-5-spring)
 - [Introduction to Lettuce – the Java Redis Client](http://www.baeldung.com/java-redis-lettuce)
 - [A Guide to Jdbi](http://www.baeldung.com/jdbi)
 - [Pessimistic Locking in JPA](http://www.baeldung.com/jpa-pessimistic-locking)
@@ -14,3 +13,5 @@
 - [Spring Data JPA – Derived Delete Methods](https://www.baeldung.com/spring-data-jpa-deleteby)
 - [Difference Between save() and saveAndFlush() in Spring Data JPA](https://www.baeldung.com/spring-data-jpa-save-saveandflush)
 - [Spring Boot with Hibernate](https://www.baeldung.com/spring-boot-hibernate)
+- [Persisting Maps with Hibernate](https://www.baeldung.com/hibernate-persisting-maps)
+- [Difference Between @Size, @Length, and @Column(length=value)](https://www.baeldung.com/jpa-size-length-column-differences)

persistence-modules/java-mongodb/README.md

@@ -2,3 +2,4 @@
 
 - [A Guide to MongoDB with Java](http://www.baeldung.com/java-mongodb)
 - [A Simple Tagging Implementation with MongoDB](http://www.baeldung.com/mongodb-tagging)
+- [MongoDB BSON Guide](https://www.baeldung.com/mongodb-bson)

persistence-modules/spring-data-jpa-2/README.md

@@ -1,15 +1,14 @@
-=========
-
-## Spring Data JPA Example Project
-
-### Relevant Articles: 
-- [Spring Data JPA – Derived Delete Methods](https://www.baeldung.com/spring-data-jpa-deleteby)
-- [JPA Join Types](https://www.baeldung.com/jpa-join-types)
-- [Case Insensitive Queries with Spring Data Repository](https://www.baeldung.com/spring-data-case-insensitive-queries)
-- [The Exists Query in Spring Data](https://www.baeldung.com/spring-data-exists-query)
-- [Spring Data JPA Repository Populators](https://www.baeldung.com/spring-data-jpa-repository-populators)
-- [Spring Data JPA and Null Parameters](https://www.baeldung.com/spring-data-jpa-null-parameters)
-- [Spring Data JPA Projections](https://www.baeldung.com/spring-data-jpa-projections)
-- [JPA @Embedded And @Embeddable](https://www.baeldung.com/jpa-embedded-embeddable)
-- [Spring Data JPA Delete and Relationships](https://www.baeldung.com/spring-data-jpa-delete)
-
+=========
+
+## Spring Data JPA Example Project
+
+### Relevant Articles: 
+- [Spring Data JPA – Derived Delete Methods](https://www.baeldung.com/spring-data-jpa-deleteby)
+- [JPA Join Types](https://www.baeldung.com/jpa-join-types)
+- [Case Insensitive Queries with Spring Data Repository](https://www.baeldung.com/spring-data-case-insensitive-queries)
+- [The Exists Query in Spring Data](https://www.baeldung.com/spring-data-exists-query)
+- [Spring Data JPA Repository Populators](https://www.baeldung.com/spring-data-jpa-repository-populators)
+- [Spring Data JPA and Null Parameters](https://www.baeldung.com/spring-data-jpa-null-parameters)
+- [Spring Data JPA Projections](https://www.baeldung.com/spring-data-jpa-projections)
+- [JPA @Embedded And @Embeddable](https://www.baeldung.com/jpa-embedded-embeddable)
+- [Spring Data JPA Delete and Relationships](https://www.baeldung.com/spring-data-jpa-delete)

persistence-modules/spring-hibernate4/README.md

@@ -4,7 +4,6 @@
 
 ### Relevant Articles: 
 - [Guide to Hibernate 4 with Spring](http://www.baeldung.com/hibernate-4-spring)
-- [The DAO with Spring and Hibernate](http://www.baeldung.com/persistence-layer-with-spring-and-hibernate)
 - [Hibernate Pagination](http://www.baeldung.com/hibernate-pagination)
 - [Sorting with Hibernate](http://www.baeldung.com/hibernate-sort)
 - [Stored Procedures with Hibernate](http://www.baeldung.com/stored-procedures-with-hibernate-tutorial)

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

@@ -5,6 +5,9 @@
 
 ### Relevant Articles: 
 - [A Guide to JPA with Spring](https://www.baeldung.com/the-persistence-layer-with-spring-and-jpa)
+- [Bootstrapping Hibernate 5 with Spring](http://www.baeldung.com/hibernate-5-spring)
+- [The DAO with Spring and Hibernate](http://www.baeldung.com/persistence-layer-with-spring-and-hibernate)
+
 
 
 ### Eclipse Config 

persistence-modules/spring-persistence-simple/pom.xml

@@ -32,7 +32,16 @@
         </dependency>
 
         <!-- persistence -->
-
+        <dependency>
+            <groupId>org.hibernate</groupId>
+            <artifactId>hibernate-core</artifactId>
+            <version>${hibernate.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.transaction</groupId>
+            <artifactId>jta</artifactId>
+            <version>${jta.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.hibernate</groupId>
             <artifactId>hibernate-entitymanager</artifactId>
@@ -55,6 +64,12 @@
             <version>${h2.version}</version>
         </dependency>
 
+        <dependency>
+            <groupId>org.apache.tomcat</groupId>
+            <artifactId>tomcat-dbcp</artifactId>
+            <version>${tomcat-dbcp.version}</version>
+        </dependency>
+
         <!-- utils -->
 
         <dependency>
@@ -104,6 +119,8 @@
         <hibernate.version>5.4.2.Final</hibernate.version>
         <mysql-connector-java.version>6.0.6</mysql-connector-java.version>
         <spring-data-jpa.version>2.1.6.RELEASE</spring-data-jpa.version>
+        <tomcat-dbcp.version>9.0.0.M26</tomcat-dbcp.version>
+        <jta.version>1.1</jta.version>
 
         <!-- util -->
         <guava.version>21.0</guava.version>

persistence-modules/spring-persistence-simple/src/main/java/com/baeldung/hibernate/bootstrap/BarHibernateDAO.java

@@ -0,0 +1,39 @@
+package com.baeldung.hibernate.bootstrap;
+
+import com.baeldung.hibernate.bootstrap.model.TestEntity;
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+
+public abstract class BarHibernateDAO {
+
+    @Autowired
+    private SessionFactory sessionFactory;
+
+    public TestEntity findEntity(int id) {
+
+        return getCurrentSession().find(TestEntity.class, 1);
+    }
+
+    public void createEntity(TestEntity entity) {
+
+        getCurrentSession().save(entity);
+    }
+
+    public void createEntity(int id, String newDescription) {
+
+        TestEntity entity = findEntity(id);
+        entity.setDescription(newDescription);
+        getCurrentSession().save(entity);
+    }
+
+    public void deleteEntity(int id) {
+
+        TestEntity entity = findEntity(id);
+        getCurrentSession().delete(entity);
+    }
+
+    protected Session getCurrentSession() {
+        return sessionFactory.getCurrentSession();
+    }
+}

persistence-modules/spring-persistence-simple/src/main/java/com/baeldung/hibernate/bootstrap/HibernateConf.java

@@ -0,0 +1,61 @@
+package com.baeldung.hibernate.bootstrap;
+
+import com.google.common.base.Preconditions;
+import org.apache.tomcat.dbcp.dbcp2.BasicDataSource;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.PropertySource;
+import org.springframework.core.env.Environment;
+import org.springframework.orm.hibernate5.HibernateTransactionManager;
+import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+import javax.sql.DataSource;
+import java.util.Properties;
+
+@Configuration
+@EnableTransactionManagement
+@PropertySource({ "classpath:persistence-h2.properties" })
+public class HibernateConf {
+
+    @Autowired
+    private Environment env;
+
+    @Bean
+    public LocalSessionFactoryBean sessionFactory() {
+        final LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
+        sessionFactory.setDataSource(dataSource());
+        sessionFactory.setPackagesToScan(new String[] { "com.baeldung.hibernate.bootstrap.model" });
+        sessionFactory.setHibernateProperties(hibernateProperties());
+
+        return sessionFactory;
+    }
+
+    @Bean
+    public DataSource dataSource() {
+        final BasicDataSource dataSource = new BasicDataSource();
+        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 hibernateTransactionManager() {
+        final HibernateTransactionManager transactionManager = new HibernateTransactionManager();
+        transactionManager.setSessionFactory(sessionFactory().getObject());
+        return transactionManager;
+    }
+
+    private final Properties hibernateProperties() {
+        final Properties hibernateProperties = new Properties();
+        hibernateProperties.setProperty("hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto"));
+        hibernateProperties.setProperty("hibernate.dialect", env.getProperty("hibernate.dialect"));
+
+        return hibernateProperties;
+    }
+}

persistence-modules/spring-persistence-simple/src/main/java/com/baeldung/hibernate/bootstrap/HibernateXMLConf.java

@@ -0,0 +1,24 @@
+package com.baeldung.hibernate.bootstrap;
+
+import com.google.common.base.Preconditions;
+import org.apache.tomcat.dbcp.dbcp2.BasicDataSource;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.ImportResource;
+import org.springframework.context.annotation.PropertySource;
+import org.springframework.core.env.Environment;
+import org.springframework.orm.hibernate5.HibernateTransactionManager;
+import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.annotation.EnableTransactionManagement;
+
+import javax.sql.DataSource;
+import java.util.Properties;
+
+@Configuration
+@EnableTransactionManagement
+@ImportResource({ "classpath:hibernate5Configuration.xml" })
+public class HibernateXMLConf {
+
+}

persistence-modules/spring-persistence-simple/src/main/java/com/baeldung/hibernate/bootstrap/model/TestEntity.java

@@ -0,0 +1,29 @@
+package com.baeldung.hibernate.bootstrap.model;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+
+@Entity
+public class TestEntity {
+
+    private int id;
+
+    private String description;
+
+    @Id
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+}

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

@@ -0,0 +1,14 @@
+package com.baeldung.persistence.dao.common;
+
+import java.io.Serializable;
+
+import com.google.common.base.Preconditions;
+
+public abstract class AbstractDao<T extends Serializable> implements IOperations<T> {
+
+    protected Class<T> clazz;
+
+    protected final void setClazz(final Class<T> clazzToSet) {
+        clazz = Preconditions.checkNotNull(clazzToSet);
+    }
+}

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

@@ -0,0 +1,59 @@
+package com.baeldung.persistence.dao.common;
+
+import java.io.Serializable;
+import java.util.List;
+
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+
+import com.google.common.base.Preconditions;
+
+@SuppressWarnings("unchecked")
+public abstract class AbstractHibernateDao<T extends Serializable> extends AbstractDao<T> implements IOperations<T> {
+
+    @Autowired
+    protected SessionFactory sessionFactory;
+
+    // API
+
+    @Override
+    public T findOne(final long id) {
+        return (T) getCurrentSession().get(clazz, id);
+    }
+
+    @Override
+    public List<T> findAll() {
+        return getCurrentSession().createQuery("from " + clazz.getName()).list();
+    }
+
+    @Override
+    public void create(final T entity) {
+        Preconditions.checkNotNull(entity);
+        getCurrentSession().saveOrUpdate(entity);
+    }
+
+    @Override
+    public T update(final T entity) {
+        Preconditions.checkNotNull(entity);
+        return (T) getCurrentSession().merge(entity);
+    }
+
+    @Override
+    public void delete(final T entity) {
+        Preconditions.checkNotNull(entity);
+        getCurrentSession().delete(entity);
+    }
+
+    @Override
+    public void deleteById(final long entityId) {
+        final T entity = findOne(entityId);
+        Preconditions.checkState(entity != null);
+        delete(entity);
+    }
+
+    protected Session getCurrentSession() {
+        return sessionFactory.getCurrentSession();
+    }
+
+}

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

@@ -0,0 +1,20 @@
+package com.baeldung.persistence.dao.common;
+
+import java.io.Serializable;
+import java.util.List;
+
+public interface IOperations<T extends Serializable> {
+
+    T findOne(final long id);
+
+    List<T> findAll();
+
+    void create(final T entity);
+
+    T update(final T entity);
+
+    void delete(final T entity);
+
+    void deleteById(final long entityId);
+
+}

persistence-modules/spring-persistence-simple/src/main/java/com/baeldung/persistence/dao/impl/FooDao.java

@@ -0,0 +1,20 @@
+package com.baeldung.persistence.dao.impl;
+
+import org.baeldung.persistence.dao.IFooDao;
+import org.baeldung.persistence.model.Foo;
+import org.springframework.stereotype.Repository;
+
+import com.baeldung.persistence.dao.common.AbstractHibernateDao;
+
+@Repository
+public class FooDao extends AbstractHibernateDao<Foo> implements IFooDao {
+
+    public FooDao() {
+        super();
+
+        setClazz(Foo.class);
+    }
+
+    // API
+
+}