Documentation Examples Tutorials JAR files Leaks Errata

/shared/HibernateHelper.java package shared; import java.io.IOException; import java.util.ArrayList; import java.util.List; import java.util.Properties; import javax.servlet.ServletException; import javax.servlet.http.HttpServletResponse; import org.apache.log4j.Logger; import org.hibernate.Criteria; import org.hibernate.HibernateException; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.cfg.AnnotationConfiguration; import org.hibernate.cfg.Configuration; import org.hibernate.cfg.Environment; import org.hibernate.criterion.Restrictions; public class HibernateHelper { static protected Logger log = Logger.getLogger("bytesizebook.webdev"); static protected List<Class> listClasses = new ArrayList<Class>(); static protected SessionFactory sessionFactory; static protected Exception lastError; static public void initSessionFactory(Properties props, Class... mappings) { //if there is a new mapping class, then restart the factory. if (addMappings(listClasses, mappings)) { closeFactory(sessionFactory); sessionFactory = createFactory(props, listClasses); } } static public void initSessionFactory(Class... mappings) { initSessionFactory(null, mappings); } static public void createTable(Properties props, Class... mappings) { List<Class> tempList = new ArrayList<Class>(); SessionFactory tempFactory = null; addMappings(tempList, mappings); if (props == null) props = new Properties(); props.setProperty(Environment.HBM2DDL_AUTO, "create"); //the temp factory is only needed to create the tables. tempFactory = createFactory(props, tempList); closeFactory(tempFactory); } static public void createTable(Class... mappings) { createTable(null, mappings); } static protected boolean addMappings(List<Class> list, Class... mappings) { boolean bNewClass = false; for (Class mapping : mappings) { if (!list.contains(mapping)) { list.add(mapping); bNewClass = true; } } return bNewClass; } static protected SessionFactory createFactory( Properties props, List<Class> list) { SessionFactory factory = null; //Config will interpret annotations AnnotationConfiguration cfg = new AnnotationConfiguration(); try { //add the properties to the config if (props != null) cfg.addProperties(props); //read from the hibernate.cfg.xml file. Notice that the xml file //overwrites properties from the prop list. Switch the order of the //above statement with this one, if you prefer to have the props //overwrite the config file. configureFromFile(cfg); //Add the annotated bean classes for this app for (Class mapping : list) { cfg.addAnnotatedClass(mapping); } factory = buildFactory(cfg); testConnection(factory); } catch (Exception ex) { //Make sure to log the exception, //as it might be swallowed. log.error("SessionFactory creation failed.", ex); lastError = ex; closeFactory(factory); factory = null; } return factory; } static protected void configureFromFile(Configuration cfg) throws Exception { try { cfg.configure(); } catch (HibernateException ex) { if (ex.getMessage().equals( "/hibernate.cfg.xml not found")) { log.warn(ex.getMessage()); } else { log.error("Error in hibernate " + "configuration file.", ex); throw ex; } } } static protected SessionFactory buildFactory(Configuration cfg) throws Exception { SessionFactory factory = null; try { factory = cfg.buildSessionFactory(); } catch (Exception ex) { log.error("Could not build the factory", ex); closeFactory(factory); factory = null; throw ex; } return factory; } static protected void testConnection(SessionFactory factory) throws Exception { Session session = null; try { session = factory.openSession(); Transaction tran = session.beginTransaction(); someDatabaseProcess(); tran.commit(); session.close(); } catch (Exception ex) { log.error("Database transaction failed.", ex); if (session != null) session.close(); throw ex; } } static protected void someDatabaseProcess() {} static public void closeFactory(SessionFactory factory) { if (factory != null) { factory.close(); } } static public void closeFactory() { closeFactory(sessionFactory); } static public Exception getLastError() { return lastError; } static public void updateDB(Object obj) { Session session = null; try { session = sessionFactory.openSession(); Transaction tx = session.beginTransaction(); session.saveOrUpdate(obj); tx.commit(); } finally { if (session != null) session.close(); } } static public void updateDB(java.util.List list) { Session session = sessionFactory.openSession(); Transaction tx = session.beginTransaction(); for(Object obj : list) { session.saveOrUpdate(obj); } tx.commit(); session.close(); } static public void saveDB(Object obj) { Session session = null; try { session = sessionFactory.openSession(); Transaction tx = session.beginTransaction(); session.save(obj); tx.commit(); } finally { if (session != null) session.close(); } } static public void removeDB(Object obj) { Session session = null; try { session = sessionFactory.openSession(); Transaction tx = session.beginTransaction(); session.delete(obj); tx.commit(); } finally { if (session != null) session.close(); } } static public java.util.List getListData( Class classBean, String strKey, Object value) { java.util.List result = new java.util.ArrayList(); Session session = sessionFactory.openSession(); Transaction tx = session.beginTransaction(); Criteria criteria = session.createCriteria(classBean); if (strKey != null) { criteria.add(Restrictions.like(strKey, value)); } result = criteria.list(); tx.commit(); session.close(); return result; } static public java.util.List getListData( Class classBean) { return getListData(classBean, null, null); } static public Object getFirstMatch( Class classBean, String strKey, Object value) { java.util.List records = getListData(classBean, strKey, value); if (records != null && records.size() > 0) { return records.get(0); } return null; } static public Object getFirstMatch( Object data, String strKey, Object value) { return getFirstMatch(data.getClass(), strKey, value); } static public Object getKeyData(Class beanClass, long itemId) { Object data = null; Session session = sessionFactory.openSession(); data = session.get(beanClass, itemId); session.close(); return data; } static public boolean isSessionOpen() { return sessionFactory != null; } static public boolean testDB(HttpServletResponse response) throws IOException, ServletException { if (!isSessionOpen()) { writeError(response); } return isSessionOpen(); } static public void writeError(HttpServletResponse response, String title, Exception ex) throws java.io.IOException, ServletException { java.io.PrintWriter out = response.getWriter(); response.setContentType("text/html"); out.println("<html>"); out.println(" <head>"); out.println(" <title>" + title + "</title>"); out.println(" </head>"); out.println(" <body>"); out.println("<h2>" + title + "</h2>"); if (ex != null) { if (ex.getMessage() != null) { out.println( " <h3>" + ex.getMessage() + "</h3>"); } if (ex.getCause() != null) { out.println( " <h4>" + ex.getCause() + "</h4>"); } StackTraceElement[] trace = ex.getStackTrace(); if (trace != null && trace.length > 0) { out.print("<pre>"); ex.printStackTrace(out); out.println("</pre>"); } } else { out.println("Hibernate must be initialized"); } out.println(" </body>"); out.println("</html>"); out.close(); } static public void writeError(HttpServletResponse response) throws java.io.IOException, ServletException { writeError(response, "Hibernate Initialization Error", lastError); } }

Contact the author