shared
Class HibernateHelper

java.lang.Object
  shared.HibernateHelper

public class HibernateHelper
extends java.lang.Object

Helper methods for accessing Hibernate.

Field Summary

protected static java.lang.Exception	lastError The last error that was generated by Hibernate.
protected static java.util.List<java.lang.Class>	listClasses The list of classes that are known to Hibernate.
protected static org.apache.log4j.Logger	log Logger for reporting errors.
protected static org.hibernate.SessionFactory	sessionFactory The session factory that is used by Hibernate for all access.

Constructor Summary

HibernateHelper()

Method Summary

protected static boolean	addMappings(java.util.List<java.lang.Class> list, java.lang.Class... mappings) Test if the class being added is already known by Hibernate.
protected static org.hibernate.SessionFactory	buildFactory(org.hibernate.cfg.Configuration cfg) Build the factory.
static void	closeFactory() Close the factory.
static void	closeFactory(org.hibernate.SessionFactory factory) Close the factory.
protected static void	configureFromFile(org.hibernate.cfg.Configuration cfg) Read from the hibernate.cfg.xml file.
protected static org.hibernate.SessionFactory	createFactory(java.util.Properties props, java.util.List<java.lang.Class> list) Create the session factory.
static void	createTable(java.lang.Class... mappings) Overloaded for no properties.
static void	createTable(java.util.Properties props, java.lang.Class... mappings) Create a temporary session factory to create the tables.
static java.lang.Object	getFirstMatch(java.lang.Class classBean, java.lang.String strKey, java.lang.Object value) Retreives the first record that has a field that matches the specified value.
static java.lang.Object	getFirstMatch(java.lang.Object data, java.lang.String strKey, java.lang.Object value) Overload of getFirstMatch that accepts a bean object instead of a bean class.
static java.lang.Object	getKeyData(java.lang.Class beanClass, long itemId) Retrieves the bean with the specified value for the key field
static java.lang.Exception	getLastError() Retrieve the last error generated by Hibernate.
static java.util.List	getListData(java.lang.Class classBean) Retrieve all the records from the database.
static java.util.List	getListData(java.lang.Class classBean, java.lang.String strKey, java.lang.Object value) Use a criteria object to retrieve records from the database.
static void	initSessionFactory(java.lang.Class... mappings) Overloaded initSessionFactory for not sending props.
static void	initSessionFactory(java.util.Properties props, java.lang.Class... mappings) Initialise the session factory that Hibernate uses for all access.
static boolean	isSessionOpen() Tests if the sessionFactory exists.
static void	removeDB(java.lang.Object obj) Call the Hibernate method delete.
static void	saveDB(java.lang.Object obj) Call the Hibernate method save.
protected static void	someDatabaseProcess() A dummy method, used to test if the database is open.
protected static void	testConnection(org.hibernate.SessionFactory factory) Test if the connection to the database works.
static boolean	testDB(javax.servlet.http.HttpServletResponse response) Tests if a database operation will succeed on the sessionFactory.
static void	updateDB(java.util.List list) Call the Hibernate method saveOrUpdate.
static void	updateDB(java.lang.Object obj) Call the Hibernate method saveOrUpdate.
static void	writeError(javax.servlet.http.HttpServletResponse response) Writes an error page for the last generated error
static void	writeError(javax.servlet.http.HttpServletResponse response, java.lang.String title, java.lang.Exception ex) Writes an error message to the response.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

log

protected static org.apache.log4j.Logger log

Logger for reporting errors.

listClasses

protected static java.util.List<java.lang.Class> listClasses

The list of classes that are known to Hibernate.

sessionFactory

protected static org.hibernate.SessionFactory sessionFactory

The session factory that is used by Hibernate for all access.

lastError

protected static java.lang.Exception lastError

The last error that was generated by Hibernate.

Constructor Detail

HibernateHelper

public HibernateHelper()

Method Detail

initSessionFactory

public static void initSessionFactory(java.util.Properties props,
                                      java.lang.Class... mappings)

Initialise the session factory that Hibernate uses for all access.

Parameters:

props - Properties for initalising Hibernate

mappings - The classes that are to be mapped by Hibernate

initSessionFactory

public static void initSessionFactory(java.lang.Class... mappings)

Overloaded initSessionFactory for not sending props.

Parameters:

mappings - The list of classes that are to be mapped.

createTable

public static void createTable(java.util.Properties props,
                               java.lang.Class... mappings)

Create a temporary session factory to create the tables.

Parameters:

props - The properties to initialise Hibernate

mappings - The classes to be mapped in Hibernate

createTable

public static void createTable(java.lang.Class... mappings)

Overloaded for no properties.

Parameters:

mappings - The classes to be mapped in Hibernate

addMappings

protected static boolean addMappings(java.util.List<java.lang.Class> list,
                                     java.lang.Class... mappings)

Test if the class being added is already known by Hibernate.

Parameters:

list - The list of known classes

mappings - The new mappings being added

Returns:

true if there is a new class in the mappings

createFactory

protected static org.hibernate.SessionFactory createFactory(java.util.Properties props,
                                                            java.util.List<java.lang.Class> list)

Create the session factory.

Parameters:

props - The properties to initialise Hibernate

list - The list of classes to be mapped in Hibernate

Returns:

the session factory

configureFromFile

protected static void configureFromFile(org.hibernate.cfg.Configuration cfg)
                                 throws java.lang.Exception

Read from the hibernate.cfg.xml file.

Parameters:

cfg - The configuration for initialising Hibernate

Throws:

java.lang.Exception

buildFactory

protected static org.hibernate.SessionFactory buildFactory(org.hibernate.cfg.Configuration cfg)
                                                    throws java.lang.Exception

Build the factory. Log errors.

Parameters:

cfg - The configuration for initialising Hibernate

Returns:

Throws:

java.lang.Exception

testConnection

protected static void testConnection(org.hibernate.SessionFactory factory)
                              throws java.lang.Exception

Test if the connection to the database works.

Parameters:

factory - The initialised session factory

Throws:

java.lang.Exception

someDatabaseProcess

protected static void someDatabaseProcess()

A dummy method, used to test if the database is open.

closeFactory

public static void closeFactory(org.hibernate.SessionFactory factory)

Close the factory.

Parameters:

factory - The initialise session factory

closeFactory

public static void closeFactory()

Close the factory.

getLastError

public static java.lang.Exception getLastError()

Retrieve the last error generated by Hibernate.

Returns:

last error

updateDB

public static void updateDB(java.lang.Object obj)

Call the Hibernate method saveOrUpdate. Hibernate uses transactions and sessions to access the database. If the object is already in the database, then an update will occur; otherwise, a save of a new record occurs.

Parameters:

obj - The object to save to the database

updateDB

public static void updateDB(java.util.List list)

Call the Hibernate method saveOrUpdate. Hibernate uses transactions and sessions to access the database. If the object is already in the database, then an update will occur; otherwise, a save of a new record occurs.

Parameters:

list - The list of obejcts to save or update

saveDB

public static void saveDB(java.lang.Object obj)

Call the Hibernate method save. Hibernate uses transactions and sessions to access the database. A new row will always be added to the database.

Parameters:

obj - The object to save to the database

removeDB

public static void removeDB(java.lang.Object obj)

Call the Hibernate method delete. Hibernate uses transactions and sessions to access the database. The associated row will be deleted from the database.

Parameters:

obj - The object to delete from the database

getListData

public static java.util.List getListData(java.lang.Class classBean,
                                         java.lang.String strKey,
                                         java.lang.Object value)

Use a criteria object to retrieve records from the database.

Hibernate uses transactions and sessions to access the database. Retrieves a list of beans whose field matches the given value.

Parameters:

classBean - The bean class

strKey - The field name

value - The value of the field

Returns:

The list of beans whose key matches the value

getListData

public static java.util.List getListData(java.lang.Class classBean)

Retrieve all the records from the database.

Hibernate uses transactions and sessions to access the database. Retrieves all the records from the database in a list.

Parameters:

classBean -

Returns:

getFirstMatch

public static java.lang.Object getFirstMatch(java.lang.Class classBean,
                                             java.lang.String strKey,
                                             java.lang.Object value)

Retreives the first record that has a field that matches the specified value.

Parameters:

classBean - The bean class for the database table

strKey - The field to search

value - The value to match

Returns:

The first bean that whose field matches the value

getFirstMatch

public static java.lang.Object getFirstMatch(java.lang.Object data,
                                             java.lang.String strKey,
                                             java.lang.Object value)

Overload of getFirstMatch that accepts a bean object instead of a bean class. Retreives the first record that has a field that matches the specified value.

Parameters:

data - A bean object that matches the bean class for the database

strKey - The field to search

value - The value to match

Returns:

The first bean that whose field matches the value

getKeyData

public static java.lang.Object getKeyData(java.lang.Class beanClass,
                                          long itemId)

Retrieves the bean with the specified value for the key field

Parameters:

beanClass - The class for the database

itemId - The id for the bean

Returns:

The bean whose key field matches the value

isSessionOpen

public static boolean isSessionOpen()

Tests if the sessionFactory exists.

Returns:

true/false if session is open/closed

testDB

public static boolean testDB(javax.servlet.http.HttpServletResponse response)
                      throws java.io.IOException,
                             javax.servlet.ServletException

Tests if a database operation will succeed on the sessionFactory.

Parameters:

response - Response information encapsulated in a Java object

Returns:

true if the sessionFactory performs the operation

Throws:

java.io.IOException

javax.servlet.ServletException

writeError

public static void writeError(javax.servlet.http.HttpServletResponse response,
                              java.lang.String title,
                              java.lang.Exception ex)
                       throws java.io.IOException,
                              javax.servlet.ServletException

Writes an error message to the response.

Parameters:

response - Response information encapsulated in a Java object

title - Title for the page

ex - Exception that caused the error

Throws:

java.io.IOException

javax.servlet.ServletException

writeError

public static void writeError(javax.servlet.http.HttpServletResponse response)
                       throws java.io.IOException,
                              javax.servlet.ServletException

Writes an error page for the last generated error

Parameters:

response - Response information encapsulated in a Java object

Throws:

java.io.IOException

javax.servlet.ServletException