com.hartveld.commons.db.DAOBase.java Source code

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Here is the source code for com.hartveld.commons.db.DAOBase.java

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/*
 * Copyright (c) 2013 David Hartveld
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.hartveld.commons.db;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static org.apache.commons.lang3.StringUtils.isNotEmpty;

import java.util.Collection;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityNotFoundException;
import javax.persistence.TypedQuery;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public abstract class DAOBase<T extends EntityBase> implements DAO<T> {

    private static final Logger LOG = LoggerFactory.getLogger(DAOBase.class);

    private final EntityManager em;

    private final Class<T> entityClass;
    private final String entityName;

    protected DAOBase(final EntityManager em, final Class<T> clazz) {
        checkNotNull(em, "em");
        checkNotNull(clazz, "clazz");

        this.em = em;
        this.entityClass = clazz;
        this.entityName = clazz.getSimpleName();
    }

    @Override
    public final EntityManager getEntityManager() {
        return em;
    }

    @Override
    public final void flush() {
        em.flush();
    }

    @Override
    public final Class<T> getEntityClass() {
        return entityClass;
    }

    @Override
    public final String getEntityName() {
        return entityName;
    }

    @Override
    public final void persist(final EntityBase entity) {
        LOG.trace("persist: {}", entity);

        checkNotNull(entity, "entity");

        em.persist(entity);
    }

    @Override
    public final void persistAll(final EntityBase... entities) {
        LOG.trace("persistAll: {}", (Object) entities);

        for (final EntityBase entity : entities) {
            persist(entity);
        }
    }

    @Override
    public final void persistAll(final Collection<? extends EntityBase> entities) {
        LOG.trace("persistAll: {}", entities);

        for (final EntityBase entity : entities) {
            persist(entity);
        }
    }

    @Override
    public final void remove(final EntityBase entity) {
        LOG.trace("remove: {}", entity);

        checkNotNull(entity, "entity");

        em.remove(entity);
    }

    @Override
    public void removeById(final long id) {
        LOG.trace("removeById: {}", id);

        final T entity = em.find(entityClass, id);

        if (entity != null) {
            em.remove(entity);
        } else {
            throw new EntityNotFoundException(
                    "Entity of type '" + entityName + "' with id '" + id + "' does not exist");
        }
    }

    @Override
    public List<T> retrieveAll() {
        LOG.trace("retrieveAll:");

        final TypedQuery<T> query = em.createQuery("from " + entityName, entityClass);

        return query.getResultList();
    }

    @Override
    public T retrieveById(final long id) {
        LOG.trace("retrieveById: {}", id);

        final TypedQuery<T> query = em.createQuery("from " + entityName + " where id = :id", entityClass);

        query.setParameter("id", id);

        return query.getSingleResult();
    }

    protected final TypedQuery<T> createQuery(final String query) {
        LOG.trace("createQuery: {}", query);

        checkArgument(isNotEmpty(query), "query must be non-empty");

        return em.createQuery(query, entityClass);
    }

}