HibernateUtil.java

/**
 * The contents of this file are subject to the OpenMRS Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://license.openmrs.org
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * Copyright (C) OpenMRS, LLC.  All Rights Reserved.
 */
package org.openmrs.api.db.hibernate;

import java.sql.SQLException;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException;
import org.hibernate.SessionFactory;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.HSQLDialect;
import org.hibernate.engine.SessionFactoryImplementor;

/**
 * This class holds common methods and utilities that are used across the hibernate related classes
 */
public class HibernateUtil {
	
	private static Log log = LogFactory.getLog(HibernateUtil.class);
	
	private static Dialect dialect = null;
	
	private static Boolean isHSQLDialect = null;
	
	/**
	 * Check and cache whether the currect dialect is HSQL or not. This is needed because some
	 * queries are different if in the hsql world as opposed to the mysql/postgres world
	 * 
	 * @param sessionFactory
	 * @return true/false whether we're in hsql right now or not
	 */
	public static boolean isHSQLDialect(SessionFactory sessionFactory) {
		
		if (isHSQLDialect == null)
			// check and cache the dialect
			isHSQLDialect = HSQLDialect.class.getName().equals(getDialect(sessionFactory).getClass().getName());
		
		return isHSQLDialect;
	}
	
	/**
	 * Fetch the current Dialect of the given SessionFactory
	 * 
	 * @param sessionFactory SessionFactory to pull the dialect from
	 * @return Dialect of sql that this connection/session is using
	 */
	public static Dialect getDialect(SessionFactory sessionFactory) {
		
		// return cached dialect
		if (dialect != null)
			return dialect;
		
		SessionFactoryImplementor implementor = (SessionFactoryImplementor) sessionFactory;
		dialect = implementor.getDialect();
		
		if (log.isDebugEnabled())
			log.debug("Getting dialect for session: " + dialect);
		
		return dialect;
	}
	
	/**
	 * Escapes all sql wildcards in the given string, returns the same string if it doesn't contain
	 * any sql wildcards
	 * 
	 * @param oldString the string in which to escape the sql wildcards
	 * @return the string with sql wildcards escaped if any found otherwise the original string is
	 *         returned
	 */
	public static String escapeSqlWildcards(String oldString, SessionFactory sessionFactory) {
		
		//replace all sql wildcards if any
		if (!StringUtils.isBlank(oldString)) {
			
			String escapeCharacter = "";
			try {
				//get the database specific escape character from the metadata
				escapeCharacter = sessionFactory.getCurrentSession().connection().getMetaData().getSearchStringEscape();
				
			}
			catch (HibernateException e) {
				
				log.warn("Error generated", e);
			}
			catch (SQLException e) {
				
				log.warn("Error generated", e);
			}
			//insert an escape character before each sql wildcard in the search phrase                  
			return StringUtils.replaceEach(oldString, new String[] { "%", "_", "*" }, new String[] { escapeCharacter + "%",
			        escapeCharacter + "_", escapeCharacter + "*" });
		} else
			return oldString;
		
	}
	
}