Package nl.b3p.commons.jpa

Class JpaUtilServlet

java.lang.Object

nl.b3p.commons.jpa.JpaUtilServlet

All Implemented Interfaces:

javax.servlet.Servlet

public class JpaUtilServlet
extends Object
implements javax.servlet.Servlet

Servlet die persistence units kan initialiaseren bij het opstarten van de webapp en waaraan de code mbv een static methode een EntityManager kan opvragen. Init parameters: initialize-persistence-units: welke persistence units bij het initialiseren van de webapp moeten worden aangemaakt. Indien er een fout optreedt zal de webapp niet succesvol geinitialiseerd worden, dus komen fouten in de persistence unit meteen boven water. Meerdere persistence units scheiden door ',' default-persistence-unit: van welke persistence unit de entity manager moet worden teruggegeven bij aanroep van getThreadEntityManager() (dus zonder persistenceUnit parameter). Indien bij initialize-persistence-unit een enkele persistence unit wordt genoemd wordt dit automatisch de default persistence unit. Voorbeeld web.xml: JpaUtilServlet nl.b3p.commons.jpa.JpaUtilServlet initialize-persistence-units mijnPU 1

Author:

Matthijs

Constructor Summary

Constructors

Constructor	Description
JpaUtilServlet()

Method Summary

Modifier and Type	Method	Description
static void	closeThreadEntityManager()
static void	closeThreadEntityManager(String persistenceUnit)
void	destroy()
static javax.persistence.EntityManagerFactory	getEntityManagerFactory()
static javax.persistence.EntityManagerFactory	getEntityManagerFactory(String persistenceUnit)
javax.servlet.ServletConfig	getServletConfig()
String	getServletInfo()
static javax.persistence.EntityManager	getThreadEntityManager()	Returns an EntityManager for the default persistence unit.
static javax.persistence.EntityManager	getThreadEntityManager(String persistenceUnit)	Returns an EntityManager unique for the current thread for the specified persistence unit.
void	init(javax.servlet.ServletConfig config)
void	service(javax.servlet.ServletRequest req, javax.servlet.ServletResponse res)
static void	setDefaultPersistenceUnit(String pu)

Methods inherited from class java.lang.Object

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

Constructor Detail

JpaUtilServlet

public JpaUtilServlet()

Method Detail

getServletInfo

public String getServletInfo()

Specified by:

getServletInfo in interface javax.servlet.Servlet

setDefaultPersistenceUnit

public static void setDefaultPersistenceUnit(String pu)

init

public void init(javax.servlet.ServletConfig config)
          throws javax.servlet.ServletException

Specified by:

init in interface javax.servlet.Servlet

Throws:

javax.servlet.ServletException

getThreadEntityManager

public static javax.persistence.EntityManager getThreadEntityManager()
                                                              throws IllegalArgumentException

Returns an EntityManager for the default persistence unit. The default persistence unit name is configured using the "default-persistence-unit" init parameter or automatically if there is only one persistence unit configured to initialize to that unit. If there is no default persistence unit configured, this method throws an IllegalArgumentException. It's important that when the unit-of-work of the current thread is completed, the entity manager is closed using closeThreadEntityManager()!

Returns:

an EntityManager for the default persistence unit

Throws:

IllegalArgumentException

See Also:

getThreadEntityManager(java.lang.String)

getThreadEntityManager

public static javax.persistence.EntityManager getThreadEntityManager(String persistenceUnit)

Returns an EntityManager unique for the current thread for the specified persistence unit. If the EntityManagerFactory for the persistence unit hasn't been created, it is created first. This may cause an exception only at the stage the EntityManager is first requested. To see exceptions at application start, use the "initialize-persistence-units" init parameter. If the method is called for the first time in the current thread (or a previously created EntityManager was closed), a new EntityManger will be created. If an EntityManager was already created, that instance is returned. It's important that when the unit-of-work of the current thread is completed, the entity manager is closed using closeThreadEntityManager()!

Returns:

an EntityManager for the specified persistence unit

getEntityManagerFactory

public static javax.persistence.EntityManagerFactory getEntityManagerFactory()

getEntityManagerFactory

public static javax.persistence.EntityManagerFactory getEntityManagerFactory(String persistenceUnit)

closeThreadEntityManager

public static void closeThreadEntityManager()

closeThreadEntityManager

public static void closeThreadEntityManager(String persistenceUnit)

getServletConfig

public javax.servlet.ServletConfig getServletConfig()

Specified by:

getServletConfig in interface javax.servlet.Servlet

service

public void service(javax.servlet.ServletRequest req,
                    javax.servlet.ServletResponse res)
             throws javax.servlet.ServletException,
                    IOException

Specified by:

service in interface javax.servlet.Servlet

Throws:

javax.servlet.ServletException

IOException

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Servlet