tp-hibernate-project/hibernate-project/src/main/java/com/humanbooster/dao/GenericDaoImpl.java

package com.humanbooster.dao;

import org.hibernate.Session;
import org.hibernate.SessionFactory;

import java.util.List;

public abstract class GenericDaoImpl<T, ID> implements GenericDao<T, ID> {

    protected final Class<T> entityClass;
    protected SessionFactory sessionFactory;

    public GenericDaoImpl(SessionFactory sessionFactory, Class<T> entityClass) {
        this.sessionFactory = sessionFactory;
        this.entityClass = entityClass;
    }

    @Override
    public void create(T entity) {
        try (Session session = sessionFactory.openSession()) {
            session.beginTransaction();
            session.persist(entity);
            session.getTransaction().commit();
        }
    }

    @Override
    public T read(ID id) {
        try (Session session = sessionFactory.openSession()) {
            session.beginTransaction();
            T entity = session.get(entityClass, id);
            session.getTransaction().commit();
            return entity;
        }
    }

    @Override
    public void update(T entity) {
        try (Session session = sessionFactory.openSession()) {
            session.beginTransaction();
            session.merge(entity);
            session.getTransaction().commit();
        }
    }

    @Override
    public void delete(ID id) {
        try (Session session = sessionFactory.openSession()) {
            session.beginTransaction();
            T entity = session.find(entityClass, id);
            if (entity != null) session.remove(entity);
            session.getTransaction().commit();
        }
    }

    @Override
    public List<T> findAll() {
        try (Session session = sessionFactory.openSession()) {
            session.beginTransaction();
            List<T> entities = session.createQuery("from " + entityClass.getName(), entityClass).list();
            session.getTransaction().commit();
            return entities;
        }
    }
}