com.book.identification.dao.GenericHibernateDAO.java Source code

Introduction

Here is the source code for com.book.identification.dao.GenericHibernateDAO.java

Source

// Copyright 2013 fernando.hernandez

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//   http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.book.identification.dao;

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.LockOptions;
import org.hibernate.Session;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Example;

import com.book.identification.HibernateUtil;

public abstract class GenericHibernateDAO<T, ID extends Serializable> implements GenericDAO<T, ID> {

    Object object = new Object();
    private Class<T> persistentClass;
    private Session session;

    @SuppressWarnings("unchecked")
    public GenericHibernateDAO() {
        this.persistentClass = (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass())
                .getActualTypeArguments()[0];
    }

    /**
     * Obtiene la sesion activa
     * 
     * @return
     */
    public Session getSession() {
        if (session == null || !session.isOpen()) {
            session = HibernateUtil.getCurrentSession();
        }
        return session;
    }

    /**
     * Devuelve la clase que se persiste
     * 
     * @return
     */
    public Class<T> getPersistentClass() {
        return persistentClass;
    }

    /**
     * Busca por Id
     * 
     * @param id
     * @return
     */
    @SuppressWarnings("unchecked")
    public T findById(ID id, boolean lock) {
        T entity;
        if (lock)
            entity = (T) this.getSession().load(getPersistentClass(), id, LockOptions.UPGRADE);
        else {
            entity = (T) this.getSession().load(getPersistentClass(), id);
        }
        return entity;
    }

    /**
     * Trae todos los elementos
     * 
     * @return
     */
    public List<T> findAll() {
        return findByCriteria();
    }

    @SuppressWarnings("unchecked")
    public List<T> findByExample(T exampleInstance, String... excludeProperty) {
        Criteria crit = getSession().createCriteria(getPersistentClass());
        Example example = Example.create(exampleInstance);
        for (String exclude : excludeProperty) {
            example.excludeProperty(exclude);
        }
        crit.add(example);
        return crit.list();
    }

    /**
     * Guarda o Actualiza
     * 
     * @param entity
     * @return
     */
    public T makePersistent(T entity) {
        synchronized (object) {
            getSession().saveOrUpdate(entity);
        }
        return entity;
    }

    public void makeTransient(T entity) {
        getSession().delete(entity);

    }

    /**
     * Delete
     * 
     * @param entity
     */
    public void delete(T entity) {
        getSession().delete(entity);
    }

    public void flush() {
        getSession().flush();
    }

    public void clear() {
        getSession().clear();
    }

    /**
     * Use this inside subclasses as a convenience method.
     */
    @SuppressWarnings("unchecked")
    public List<T> findByCriteria(Criterion... criterion) {
        Criteria crit = getSession().createCriteria(getPersistentClass());
        for (Criterion c : criterion) {
            crit.add(c);
        }
        return crit.list();
    }

    /**
    * Obtenemos la cantidad de registros usando la query como parametro
    * @param qCount
    * @return int 
    */
    protected int getCantOfRows(String qCount, int initialPage, int cantRows) {
        int qCountResult = 0;
        Long result = (Long) getSession().createQuery(qCount).setFirstResult(initialPage).setMaxResults(cantRows)
                .uniqueResult();
        if (result != null) {
            qCountResult = result.intValue();
        }

        return qCountResult;
    }
}