package com.web.pojo;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.OneToMany;

import org.hibernate.annotations.Cascade;



@Entity
public class Company {
   
   
   @Id
   @GeneratedValue
   private int compId;
   private String companyName;
   
   @OneToMany(fetch=FetchType.LAZY,mappedBy="company")
   @Cascade(org.hibernate.annotations.CascadeType.ALL)
   private List <Department> listOfDepartment = new ArrayList<Department>();
   
   
   public List<Department> getListOfDepartment() {
      return listOfDepartment;
   }
   public void setListOfDepartment(List<Department> listOfDepartment) {
      this.listOfDepartment = listOfDepartment;
   }
   public int getCompanyId() {
      return compId;
   }
   public void setCompanyId(int companyId) {
      this.compId = companyId;
   }
   public String getCompanyName() {
      return companyName;
   }
   public void setCompanyName(String companyName) {
      this.companyName = companyName;
   }

}

package com.web.pojo;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;

import org.hibernate.annotations.Cascade;


@Entity
public class Department {
   
   @Id
   @GeneratedValue
   private int deptId;
   private String deptName;

   @ManyToOne
   @JoinColumn(name="compId")
   private Company company;
   
   @OneToMany(cascade=CascadeType.ALL,fetch=FetchType.LAZY)
   private List<Employee>listofEmployee = new ArrayList<Employee>();
   
   
   public int getDeptId() {
      return deptId;
   }
   public void setDeptId(int deptId) {
      this.deptId = deptId;
   }
   public String getDeptName() {
      return deptName;
   }
   public void setDeptName(String deptName) {
      this.deptName = deptName;
   }
   public Company getCompany() {
      return company;
   }
   public void setCompany(Company company) {
      this.company = company;
   }
   public List<Employee> getListofEmployee() {
      return listofEmployee;
   }
   public void setListofEmployee(List<Employee> listofEmployee) {
      this.listofEmployee = listofEmployee;
   }
   

}

package com.web.hibernatetier;

import java.util.ArrayList;
import java.util.List;

import com.web.HibernateUtil;
import com.web.pojo.Company;
import com.web.pojo.Department;

public class CompanyDAO {
   
         

              public void addCompany(Company company) {
         
         HibernateUtil.startHibernateSession();
         HibernateUtil.session.save(company);
         HibernateUtil.endHibernateSession();
         
      }
      
      public void addDepartmentToCompany(Department department,int compId) {
         
         HibernateUtil.startHibernateSession();
         Company company = (Company) HibernateUtil.session.get(Company.class, compId);
         company.getListOfDepartment().add(department);
         Department dept = company.getListOfDepartment().get(0);
         System.out.println(dept.getCompany().getCompanyName());
         HibernateUtil.endHibernateSession();
      }
      
      
      
      public static void main(String[] args) {
         
         
                         CompanyDAO dao = new CompanyDAO();

                        Company company = new Company();
         company.setCompanyName("ABC");

                         dao.addCompany(company);
         

         
         dao.addCompany(company);
      
         // Department Transactions

         
         Department department = new Department();
         department.setDeptName("Development");
         
         dao.addDepartmentToCompany(department, 1);
         
      }



}

public class HibernateUtil {
   
   private static SessionFactory sessionFactory ;
   public static Session session;
   
   private HibernateUtil() {
      
   }
   
   private static SessionFactory getSessionFactory() {
      
      if(sessionFactory==null) {
          sessionFactory = new Configuration().configure().buildSessionFactory();
      }
      return sessionFactory;
      
   }
   
   
   public static void startHibernateSession() {
      
      sessionFactory = getSessionFactory();
      session = sessionFactory.openSession();
      session.beginTransaction();
   }
   
   
   public static void endHibernateSession() {
      session.getTransaction().commit();
      session.close();
   }
   

}