Added DAO for Supplier (#1950)

* First commit for Hibernate 5 Multitenancy tutorial

* Changes to fix the code.

* Added hibernate begin transaction code.

* Changes to solve the multitenancy issue.

* Changes to integrate h2

* Changing configs to solve the error

* Changes to solve h2 error...

* Changes to fix H2 error.

* Cleaned POM.xml and changed entity name

* Changes table name to supplier

* Removed MySql Dep from pom.xml.

* Changes as per comment in the PR...

* Removed try-catch from test functions.

* Removing the hibernate xml config.

* Changed the formatting as per the formatter.

* Clean up after merge.

* # WARNING: head commit changed in the meantime

Merge remote-tracking branch 'upstream/master' into
hibernate5-multitenancy

Conflicts:
	hibernate5/pom.xml
	pom.xml

* Introduced Supplier DAO

* shifting hibernate properties to src/test/resouces

* removed the old test.

* Filled up the stubs in the DAO.

hibernate5/src/main/java/com/baeldung/hibernate/dao/GenericDao.java

@@ -0,0 +1,12 @@
+package com.baeldung.hibernate.dao;
+
+import java.util.List;
+
+public interface GenericDao<T> {
+    
+    void save (T entity);
+    void delete (T Entity);
+    T findByName(String name);
+    List<T> findAll();
+    void populate();
+}

hibernate5/src/main/java/com/baeldung/hibernate/dao/SupplierDao.java

@@ -0,0 +1,80 @@
+package com.baeldung.hibernate.dao;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.hibernate.Criteria;
+import org.hibernate.Session;
+import org.hibernate.SessionFactory;
+import org.hibernate.Transaction;
+import org.hibernate.criterion.Expression;
+
+import com.baeldung.hibernate.pojo.Supplier;
+
+public class SupplierDao implements GenericDao<Supplier>{
+    private SessionFactory sessionFactory;
+    private String tenant;
+    
+    public SupplierDao(SessionFactory sessionFactory, String tenant) {
+        this.sessionFactory = sessionFactory;
+        this.tenant = tenant;
+        populate();
+    }
+
+    @Override
+    public void save(Supplier entity) {
+        Session session = sessionFactory.withOptions().tenantIdentifier(tenant).openSession();
+        session.save(entity);
+    }
+
+    @Override
+    public void delete(Supplier supplier) {
+        Session session = sessionFactory.withOptions().tenantIdentifier(tenant).openSession();
+        session.delete(supplier);
+    }
+
+    @Override
+    public Supplier findByName(String name) {
+        Session session = sessionFactory.withOptions().tenantIdentifier(tenant).openSession();
+        List<Supplier> fetchedSuppliers = session.createCriteria(Supplier.class).add(Expression.eq("name", name)).list();
+        if (fetchedSuppliers.size()>0) {
+            return fetchedSuppliers.get(0);
+        }else {
+            return null;
+        }
+    }
+
+    @Override
+    public List<Supplier> findAll() {
+        Session session = sessionFactory.withOptions().tenantIdentifier(tenant).openSession();
+        return session.createCriteria(Supplier.class).list();
+    }
+
+    @Override
+    public void populate() {
+        System.out.println("Init DB1");
+        Session session = sessionFactory.withOptions().tenantIdentifier(tenant).openSession();
+        Transaction transaction = session.getTransaction();
+        
+        transaction.begin();
+        session.createSQLQuery("DROP ALL OBJECTS").executeUpdate();
+        session
+            .createSQLQuery(
+                "create table Supplier (id integer generated by default as identity, country varchar(255), name varchar(255), primary key (id))")
+            .executeUpdate();
+        Supplier genertedSupplier = generateEntityForTenant(tenant);
+        System.out.println("Inserting Supplier"+genertedSupplier);
+        save (genertedSupplier);
+        
+    }
+
+    private Supplier generateEntityForTenant(String forTenant) {
+        if (forTenant.equals("mydb1")) {
+            return new Supplier ("John","USA");
+        }
+        return new Supplier ("Miller","UK");
+    }
+    
+    
+
+}