/*
 * Copyright 2002-2012 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 org.springframework.orm.hibernate4;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException;
import org.hibernate.JDBCException;
import org.hibernate.NonUniqueObjectException;
import org.hibernate.NonUniqueResultException;
import org.hibernate.ObjectDeletedException;
import org.hibernate.PersistentObjectException;
import org.hibernate.PropertyValueException;
import org.hibernate.QueryException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.StaleObjectStateException;
import org.hibernate.StaleStateException;
import org.hibernate.TransientObjectException;
import org.hibernate.UnresolvableObjectException;
import org.hibernate.WrongClassException;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.exception.ConstraintViolationException;
import org.hibernate.exception.DataException;
import org.hibernate.exception.JDBCConnectionException;
import org.hibernate.exception.LockAcquisitionException;
import org.hibernate.exception.SQLGrammarException;
import org.hibernate.service.jdbc.connections.spi.ConnectionProvider;

import org.springframework.dao.CannotAcquireLockException;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.dao.IncorrectResultSizeDataAccessException;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.dao.InvalidDataAccessResourceUsageException;
import org.springframework.jdbc.datasource.DataSourceUtils;

/**
 * Helper class featuring methods for Hibernate Session handling.
 * Also provides support for exception translation.
 *
 * <p>Used internally by {@link HibernateTransactionManager}.
 * Can also be used directly in application code.
 *
 * @author Juergen Hoeller
 * @since 3.1
 * @see HibernateExceptionTranslator
 * @see HibernateTransactionManager
 */
public abstract class SessionFactoryUtils {

	/**
	 * Order value for TransactionSynchronization objects that clean up Hibernate Sessions.
	 * Returns {@code DataSourceUtils.CONNECTION_SYNCHRONIZATION_ORDER - 100}
	 * to execute Session cleanup before JDBC Connection cleanup, if any.
	 * @see org.springframework.jdbc.datasource.DataSourceUtils#CONNECTION_SYNCHRONIZATION_ORDER
	 */
	public static final int SESSION_SYNCHRONIZATION_ORDER =
			DataSourceUtils.CONNECTION_SYNCHRONIZATION_ORDER - 100;

	static final Log logger = LogFactory.getLog(SessionFactoryUtils.class);


	/**
	 * Determine the DataSource of the given SessionFactory.
	 * @param sessionFactory the SessionFactory to check
	 * @return the DataSource, or {@code null} if none found
	 * @see org.hibernate.engine.spi.SessionFactoryImplementor#getConnectionProvider
	 */
	public static DataSource getDataSource(SessionFactory sessionFactory) {
		if (sessionFactory instanceof SessionFactoryImplementor) {
			ConnectionProvider cp = ((SessionFactoryImplementor) sessionFactory).getConnectionProvider();
			return cp.unwrap(DataSource.class);
		}
		return null;
	}

	/**
	 * Perform actual closing of the Hibernate Session,
	 * catching and logging any cleanup exceptions thrown.
	 * @param session the Hibernate Session to close (may be {@code null})
	 * @see org.hibernate.Session#close()
	 */
	public static void closeSession(Session session) {
		if (session != null) {
			try {
				session.close();
			}
			catch (HibernateException ex) {
				logger.debug("Could not close Hibernate Session", ex);
			}
			catch (Throwable ex) {
				logger.debug("Unexpected exception on closing Hibernate Session", ex);
			}
		}
	}

	/**
	 * Convert the given HibernateException to an appropriate exception
	 * from the {@code org.springframework.dao} hierarchy.
	 * @param ex HibernateException that occured
	 * @return the corresponding DataAccessException instance
	 * @see HibernateExceptionTranslator#convertHibernateAccessException
	 * @see HibernateTransactionManager#convertHibernateAccessException
	 */
	public static DataAccessException convertHibernateAccessException(HibernateException ex) {
		if (ex instanceof JDBCConnectionException) {
			return new DataAccessResourceFailureException(ex.getMessage(), ex);
		}
		if (ex instanceof SQLGrammarException) {
			SQLGrammarException jdbcEx = (SQLGrammarException) ex;
			return new InvalidDataAccessResourceUsageException(ex.getMessage() + "; SQL [" + jdbcEx.getSQL() + "]", ex);
		}
		if (ex instanceof LockAcquisitionException) {
			LockAcquisitionException jdbcEx = (LockAcquisitionException) ex;
			return new CannotAcquireLockException(ex.getMessage() + "; SQL [" + jdbcEx.getSQL() + "]", ex);
		}
		if (ex instanceof ConstraintViolationException) {
			ConstraintViolationException jdbcEx = (ConstraintViolationException) ex;
			return new DataIntegrityViolationException(ex.getMessage()  + "; SQL [" + jdbcEx.getSQL() +
					"]; constraint [" + jdbcEx.getConstraintName() + "]", ex);
		}
		if (ex instanceof DataException) {
			DataException jdbcEx = (DataException) ex;
			return new DataIntegrityViolationException(ex.getMessage() + "; SQL [" + jdbcEx.getSQL() + "]", ex);
		}
		if (ex instanceof JDBCException) {
			return new HibernateJdbcException((JDBCException) ex);
		}
		// end of JDBCException (subclass) handling

		if (ex instanceof QueryException) {
			return new HibernateQueryException((QueryException) ex);
		}
		if (ex instanceof NonUniqueResultException) {
			return new IncorrectResultSizeDataAccessException(ex.getMessage(), 1, ex);
		}
		if (ex instanceof NonUniqueObjectException) {
			return new DuplicateKeyException(ex.getMessage(), ex);
		}
		if (ex instanceof PropertyValueException) {
			return new DataIntegrityViolationException(ex.getMessage(), ex);
		}
		if (ex instanceof PersistentObjectException) {
			return new InvalidDataAccessApiUsageException(ex.getMessage(), ex);
		}
		if (ex instanceof TransientObjectException) {
			return new InvalidDataAccessApiUsageException(ex.getMessage(), ex);
		}
		if (ex instanceof ObjectDeletedException) {
			return new InvalidDataAccessApiUsageException(ex.getMessage(), ex);
		}
		if (ex instanceof UnresolvableObjectException) {
			return new HibernateObjectRetrievalFailureException((UnresolvableObjectException) ex);
		}
		if (ex instanceof WrongClassException) {
			return new HibernateObjectRetrievalFailureException((WrongClassException) ex);
		}
		if (ex instanceof StaleObjectStateException) {
			return new HibernateOptimisticLockingFailureException((StaleObjectStateException) ex);
		}
		if (ex instanceof StaleStateException) {
			return new HibernateOptimisticLockingFailureException((StaleStateException) ex);
		}

		// fallback
		return new HibernateSystemException(ex);
	}

}
