dtu.ds.warnme.dao.impl.AbstractGenericDao.java Source code

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Here is the source code for dtu.ds.warnme.dao.impl.AbstractGenericDao.java

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/**
 * Project:   warnme-server
 * File:      AbstractGenericDao.java
 * License: 
 *            This file is licensed under GNU General Public License version 3
 *            http://www.gnu.org/licenses/gpl-3.0.txt
 *
 * Copyright: Bartosz Cichecki [ cichecki.bartosz@gmail.com ]
 * Date:      19-03-2014
 */

package dtu.ds.warnme.dao.impl;

import java.io.Serializable;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;

import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import dtu.ds.warnme.dao.GenericDao;
import dtu.ds.warnme.model.AbstractEntity;

/**
 * @author Bartosz Cichecki
 */
@Transactional(propagation = Propagation.MANDATORY)
public abstract class AbstractGenericDao<T extends AbstractEntity> implements GenericDao<T> {

    @PersistenceContext
    protected transient EntityManager manager;

    private transient final Class<T> entityClazz;

    @SuppressWarnings("unchecked")
    public AbstractGenericDao() {
        entityClazz = (Class<T>) ((java.lang.reflect.ParameterizedType) this.getClass().getGenericSuperclass())
                .getActualTypeArguments()[0];
    }

    @Override
    public boolean contains(T entity) {
        return manager.contains(entity);
    }

    @Override
    public void create(T entity) {
        manager.persist(entity);
    }

    @Override
    public void delete(T entity) {
        manager.remove(entity);
    }

    @Override
    @Transactional(readOnly = true)
    public List<T> getAll() {
        CriteriaBuilder builder = manager.getCriteriaBuilder();
        CriteriaQuery<T> criteria = builder.createQuery(entityClazz);
        Root<T> root = criteria.from(entityClazz);
        criteria.select(root);
        return manager.createQuery(criteria).getResultList();
    }

    @Override
    @Transactional(readOnly = true)
    public List<T> getAllByCriteria(CriteriaQuery<T> criteria) {
        return manager.createQuery(criteria).getResultList();
    }

    @Override
    @Transactional(readOnly = true)
    public T getByCriteria(CriteriaQuery<T> criteria) {
        List<T> result = getAllByCriteria(criteria);
        if (result.size() > 1) {
            throw new IllegalStateException();
        }
        if (result.size() != 1) {
            return null;
        }
        return result.get(0);
    }

    @Override
    @Transactional(readOnly = true)
    public T getById(Serializable id) {
        return manager.find(entityClazz, id);
    }

    @Override
    public CriteriaBuilder getCriteriaBuilder() {
        return manager.getCriteriaBuilder();
    }

    @Override
    public void setEntityManager(EntityManager manager) {
        this.manager = manager;
    }

    @Override
    public void update(T entity) {
        manager.merge(entity);
    }

}