br.com.arsmachina.dao.hibernate.WriteableDAOImpl.java Source code

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// Copyright 2007-2008 Thiago H. de Paula Figueiredo
//
// 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 br.com.arsmachina.dao.hibernate;

import java.io.Serializable;

import org.hibernate.EntityMode;
import org.hibernate.Query;
import org.hibernate.SessionFactory;
import org.hibernate.classic.Session;
import org.hibernate.metadata.ClassMetadata;

import br.com.arsmachina.dao.WriteableDAO;

/**
 * {@link WriteableDAO} implementation using Hibernate. All methods use {@link #getSession()} to get
 * a {@link Session}.
 * 
 * @author Thiago H. de Paula Figueiredo
 * @param <T> the entity class related to this DAO.
 * @param <K> the type of the field that represents the entity class' primary key.
 */
public abstract class WriteableDAOImpl<T, K extends Serializable> extends BaseHibernateDAO<T, K>
        implements WriteableDAO<T, K> {

    final private String deleteHQL;

    /**
     * Constructor that takes a {@link Class} and a {@link SessionFactory}.
     * 
     * @param clasz a {@link Class}.
     * @param sessionFactory a {@link SessionFactory}. It cannot be null.
     */
    public WriteableDAOImpl(SessionFactory sessionFactory) {
        this(null, sessionFactory);
    }

    /**
     * Constructor that takes a {@link Class} and a {@link SessionFactory}.
     * 
     * @param clasz a {@link Class}.
     * @param sessionFactory a {@link SessionFactory}. It cannot be null.
     */
    @SuppressWarnings("unchecked")
    public WriteableDAOImpl(Class<T> clasz, SessionFactory sessionFactory) {

        super(clasz, sessionFactory);
        deleteHQL = createDeleteHQL();

    }

    /**
     * Creates an HQL query used to delete an object given its primary key value.
     * 
     * @return a {@link String}.
     */
    String createDeleteHQL() {

        return "delete from " + getEntityClass().getName() + " where " + getPrimaryKeyPropertyName() + " = :id";

    }

    public void delete(K id) {

        Query query = getSession().createQuery(deleteHQL);
        query.setParameter("id", id);
        query.executeUpdate();

    }

    public void delete(T object) {
        getSession().delete(object);
    }

    public void evict(T object) {
        getSession().evict(object);
    }

    public void save(T object) {
        getSession().save(object);
    }

    public T update(T object) {

        if (isPersistent(object) == false) {
            throw new IllegalArgumentException("Object not persistent");
        }

        getSession().update(object);
        return object;

    }

    /**
     * Returns <code>true</code> if the primary key field (identifier) of the given object is not
     * null. Its value is obtained via {@link ClassMetadata#getIdentifier(Object, EntityMode)}.
     * 
     * @see br.com.arsmachina.dao.WriteableDAO#isPersistent(java.lang.Object)
     * @throws IllegalArgumentException if <code>object</code> is null.
     */
    public boolean isPersistent(T object) {

        if (object == null) {
            throw new IllegalArgumentException("Parameter object cannot be null");
        }

        return getClassMetadata().getIdentifier(object, EntityMode.POJO) != null;

    }

}