Enterprise Java Beans

1
???? ? Enterprise Java Beans

• ?????????? ?? ??????? ??????

• ??????? ?
• ???????? ??????????? ??. ??????? ????????
• ???
• ??????????? ???????????
• 4 ???? 6 ????
• ???. ?????. 42452
• ?? ???? ?????????? ????????? ??????????

2
??????????

• ???? ? EJB ?????????????.
• ???? ??? ?????????????? ?? EJB-??.
• ?????????????? ?? ????????????.
• Session Beans ??????????????. Statefull ?
  Stateless Session Beans.
• Entity Beans ??????????????. Container-managed
  ? Bean-managed Entity Beans.
• ??????? ?? Session ? Entity Beans. ???????.
  ???????????? ?? Home Inteface - lookup ?? ??????.
• ???????? ?? ?????????? ??? Session ? Entity
  Beans.
• EJB environment.
• Security management.
• EJB deployment descriptor.
• EJB jar file.
• Application Servers.
• ???????.

3
???? ? EJB ?????????????.

• ???????????? ??????????? ? ??????? ?????????.

4
???? ? ?????????????? ?? EJB-??.

• ????????????? ?? EJB-?? (EJB developer)
• ????, ????? ????????? ???????????? (EJB deployer)
• ????????????? ?? ????????? (EJB container vendor)
• ????????????? ?? ?????? (EJB server vendor)
• ????????????? ?? ?????????? ??????? (application
  developer)

5
?????????????? ?? ????????????.

• ???? ??????????????
• ?????? ??????????? ?????
• Home Interface
• Remote Interface
• Session ?????? ?????????? ?? ?? ??????
  ?????? ????? ?? ????????? ?????????? ?? ??
  ????????? ? ?????? ?? ???? ????? ?? ????? ??
  ?????????? ???? ????? ?????? ???????????
  ?????? ??? ? ?????????? ??????? crash ??
  ????????? ? ?????? ?? ?? ???????? ???? ????? ??
  ???????
• Entity ?????? ??????????? ???????? ?????? ??
  ?????? ????? ??????????? ??????? ?????? ?? ?????
  ??????? ????? ?? ?????? ????? ????? ??
  ?????????? crash ?? ??????????
• CORBA

6
Session Beans. Statefull ? Stateless Session
Beans.

• ?????????? ?? dewelopera. ?? ??????????
  SessionBean ?????, Home ? Remote
  ????????????
• Home ????????? ?????????? ?????????? ?? ?????????
  ?? ??? ????? ?????????? ?? Sessio
  ????? ??????? ?? javax.ejbEJBMetaData ?????????
  ??? session bean-? ?????????? ?? handle ???
  ??????????.
• Stateless Session Beans ????????? stateless
  service.
• Statefull Session Beans ?????????? statefull
  service.
• Activation and passivation (secodary storage).

7
Entity Beans. Container-managed ? Bean-managed
Entity Beans.

• Create ??????
• Finder ??????
• Remove ??????
• Bean-managed persistence ???????????? ??
  ejbCreate(), ejbRemove(), ejbLoad(), ejbStore(),
  ejbFind()
• Container-managed persistemce

8
??????? ?? Session ? Entity Beans. ???????.
???????????? ?? Home Interface lookup ?? ??????.

• ?????????? ?? RMI.
• ?????????? ?? CORBA ?? ??-java ???????.

9
Home interface
10
Remote interface
11
Bean class
12
JSP client
13
????????? ?? ??????????.

• ???? ?????????.
• ?? ????????????? ??????????.
• Bean-managed ??????????.
• Container-managed ??????????.
• ?????????? ? deployment descriptor.
• ???????? ?? ??????????.
• Isolation levels.

14
????????? ?? ??????????

• ?????????? ?? ???? ?????? ? update ?? 3 ???? ?
  ??????????
• ?????????? ?? ????????? ??????? ? update ?? 2
  ???? ? ??????????

15
???????? ?? ??????????

• NotSupported
• Required
• Supports
• RequiresNew
• Mandatory
• Never

16
EJB environment.

• ??????? ??? ??????????? ?? enwironment ????????.
• ?????? ?? ??????? ? ?????????? ?.

17
Security management

• Security Roles.

18
EJB deployment descriptor

• ???? ?????????.
• ??? ??????????, ????? ?? ??????? ?????
  (?????????? - ??????? ? ?????????? ?? ??????
  ??????????).
• ???????????? ????????, ????? bean-developera
  ?????? ?? ?????????.

19
EJB deployment descriptor ????????????
??????????

• Enterprise beans name.
• Enterprise beans class.
• Enterprise beans home interfaces.
• Enterprise beans remote interfaces.
• Enterprise beans type.
• Re-entrancy indication.
• Session beans state management type.
• Session beans transaction demarcation type.
• Entity beans persistence management.
• Entity beans primary key class.
• Container-managed fields.
• Environment entries.
• Resource manager connection factory references.
• EJB references.
• Security role references.

20
EJB deployment descriptor ... ? ????????
21
EJB deployment descriptor ... ? ????????
22
EJB jar file.

• Meta-inf/ejb-jar.xml.
• ???????.
• ???????????? ???????.

23
Application servers.

• ProSyst Application Server http//www.prosyst.bg
• InQMy Application Server http//www.inqmy.com
• Inprise Application Server http//www.borland.com
  
• Orion Application Server http//www.orionserver.c
  om
• JRun Application Server http//www.alaire.com
• ? ????? ????? ?????? ? ???????? ???????...

24
???????

• ?????? ???????? ?? SUN-Micrsystems ?? EJB-??.
  http//java.sun.com/products/ejb
• Enterprise JavaBeans ???????????? ? ?????
  ???????????? http//java.sun.com/products/ejb/doc
  s.html
• JNDI - Java Naming and Directory Interface
  http//java.sun.com/products/jndi
• JTS - Java Transaction Service
  http//java.sun.com/products/jts
• OTS CORBAservices Object Transaction Service
  http//www.omg.org/docs/formal/97-12-17.pdf
• ?????? ?? Enterprise JavaBeans (presentation)
  http//www.persistence.com