net.derquinse.common.orm.hib.HibernateGenericDAO.java Source code

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Here is the source code for net.derquinse.common.orm.hib.HibernateGenericDAO.java

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/*
 * Copyright (C) the original author or authors.
 *
 * 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 net.derquinse.common.orm.hib;

import static com.google.common.base.Preconditions.checkNotNull;

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

import net.derquinse.common.orm.Entity;
import net.derquinse.common.orm.GenericDAO;

import org.hibernate.Criteria;
import org.hibernate.LockOptions;
import org.hibernate.NonUniqueResultException;
import org.hibernate.Query;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.Criterion;

import com.google.common.base.Preconditions;

/**
 * Implementation of the Generic DAO.
 * @author Andres Rodriguez
 */
public abstract class HibernateGenericDAO<T extends Entity<ID>, ID extends Serializable>
        extends AbstractHibernateDAO implements GenericDAO<T, ID> {
    /** Persistent class. */
    private Class<T> persistentClass;

    /**
     * Constructs the DAO
     * @param sessionFactory Hibernate Session factory.
     */
    public HibernateGenericDAO(final SessionFactory sessionFactory) {
        super(sessionFactory);
        @SuppressWarnings("unchecked")
        final Class<T> type = (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass())
                .getActualTypeArguments()[0];
        this.persistentClass = type;
    }

    /**
     * Constructs the DAO.
     * @param persistentClass Persistent class.
     * @param sessionFactory Hibernate Session factory.
     */
    public HibernateGenericDAO(final Class<T> persistentClass, final SessionFactory sessionFactory) {
        super(sessionFactory);
        this.persistentClass = checkNotNull(persistentClass);
    }

    /**
     * Constructs the DAO
     */
    public HibernateGenericDAO() {
        @SuppressWarnings("unchecked")
        final Class<T> type = (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass())
                .getActualTypeArguments()[0];
        this.persistentClass = type;
    }

    /**
     * Constructs the DAO.
     * @param persistentClass Persistent class.
     */
    public HibernateGenericDAO(final Class<T> persistentClass) {
        this.persistentClass = checkNotNull(persistentClass);
    }

    /**
     * Returns the persistent class.
     * @return The persistent class.
     */
    protected final Class<T> getPersistentClass() {
        return persistentClass;
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.orm.GenericDAO#delete(java.lang.Object)
     */
    public void delete(T entity) {
        checkNotNull(entity);
        getSession().delete(entity);
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.orm.GenericDAO#deleteById(java.io.Serializable)
     */
    public void deleteById(ID id) {
        checkNotNull(id);
        T entity = findById(id, true);
        if (entity != null) {
            delete(entity);
        }
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.orm.GenericDAO#findAll()
     */
    public List<T> findAll() {
        return findByCriteria();
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.orm.GenericDAO#findById(java.io.Serializable, boolean)
     */
    @SuppressWarnings("unchecked")
    public T findById(ID id, boolean lock) {
        if (lock) {
            return (T) getSession().get(persistentClass, id, LockOptions.UPGRADE);
        }
        return (T) getSession().get(persistentClass, id);
    }

    @Override
    public Map<ID, T> findByIds(Iterable<? extends ID> ids) {
        return findByIds(newCriteria(), ids);
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.orm.GenericDAO#save(java.lang.Object)
     */
    public T save(T entity) {
        Preconditions.checkNotNull(entity);
        getSession().save(entity);
        return entity;
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.orm.GenericDAO#saveOrUpdate(java.lang.Object)
     */
    public T saveOrUpdate(T entity) {
        Preconditions.checkNotNull(entity);
        getSession().saveOrUpdate(entity);
        return entity;
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.orm.GenericDAO#update(java.lang.Object)
     */
    public T update(T entity) {
        Preconditions.checkNotNull(entity);
        getSession().update(entity);
        return entity;
    }

    /**
     * Returns a new criteria object.
     * @return A new criteria object.
     */
    protected final Criteria newCriteria() {
        return getSession().createCriteria(persistentClass);
    }

    /**
     * Returns the list of entity instances that matches the provided crtieria.
     * @param criterion Search criteria.
     * @return The results.
     */
    protected final List<T> findByCriteria(Criterion... criterion) {
        final Criteria criteria = newCriteria();
        for (Criterion c : criterion) {
            criteria.add(c);
        }
        @SuppressWarnings("unchecked")
        final List<T> list = criteria.list();
        return list;
    }

    /**
     * Returns the results of a query as a list of the persisted class.
     * @param query Query to execute.
     * @return The results.
     */
    protected final List<T> list(Query query) {
        return list(persistentClass, query);
    }

    /**
     * Returns the first result of a query returning instances of the persisted class.
     * @param query Query to execute.
     * @return The first result or {@code null} if there are no results.
     */
    protected final T first(Query query) {
        return first(persistentClass, query);
    }

    /**
     * Returns the unique result of a query returning instances of the persisted class.
     * @param query Query to execute.
     * @return The unique result or {@code null} if there are no results.
     * @throws NonUniqueResultException if there are more than one result.
     */
    protected final T unique(Query query) {
        return unique(persistentClass, query);
    }

}