2. Fall 2008 http://www.cis.ksu.edu 1 CIS 764 Database Systems Engineering L7. EJB’s

3. Fall 2008 http://www.cis.ksu.edu 2 CIS 764 Database Systems Engineering

4. Fall 2008 http://www.cis.ksu.edu 3 CIS 764 Database Systems Engineering http://www.zakon.org/robert/internet/timeline/ 1945 … V. Bush, concept of hypertext 1961 … Kleinrock paper on packet switching 1966 … Roberts, plan for ARPA net 1967 … hypertext system, Brown Univ 1969 …. ARPA net, 4 nodes 1972 … email 1974 … Cerf, Kahn … TCP paper 1981 … APRA net down, status virus 1982 … CS net 1986 … NSF net 1987 … 10 K nodes 1987 … Apple Hypercard 1988 … CERT 1989 … 100K nodes 1991 … WWW … CGI scripts (each request is separate process, non-OO)

5. Fall 2008 http://www.cis.ksu.edu 4 CIS 764 Database Systems Engineering http://www.zakon.org/robert/internet/timeline/ 1991 … WWW … CGI scripts 1992 … 1M nodes 1995 … Java 1998 … Google … servlets … JDeveloper 1999 … J2EE, servlets, EJB 1 (RMI remote objects) JSP 1 (embedded code) 2000 … 20 M web sites 2001 … JDev separate from Borland 2003 … SQL Slammer worm … EJB 2 (adds QL ) … JSP 2 (tags ) 2005 … YouTube … Java annotations 2006 … Google buys YouTube … EJB 3 ( annotated POJO’s)

6. Fall 2008 http://www.cis.ksu.edu 5 CIS 764 Database Systems Engineering EJB specification details how an application server provides:application server Persistence Transaction processing Concurrency control Events using Java Message ServiceEventsJava Message Service Java Naming and directory services (JNDI)directory servicesJNDI Security ( Java Cryptography Extension (JCE) and JAAS )SecurityJava Cryptography Extension (JCE)JAAS Deployment of software components in an application serverDeploymentsoftware components Remote procedure calls using RMI-IIOP.Remote procedure callsRMI-IIOP Exposing business methods as Web Services.Web Services defines the roles played by the EJB container vs the EJBs From http://en.wikipedia.org/wiki/Enterprise_JavaBean http://en.wikipedia.org/wiki/Enterprise_JavaBean

7. Fall 2008 http://www.cis.ksu.edu 6 CIS 764 Database Systems Engineering … old EJB 1, 2

8. Fall 2008 http://www.cis.ksu.edu 7 CIS 764 Database Systems Engineering

9. Fall 2008 http://www.cis.ksu.edu 8 CIS 764 Database Systems Engineering EJB3 POJO + Annotations => EJB EJB 3.0 Resources http://www.oracle.com/technology/tech/java/ejb30.html Introduction: http://www.oracle.com/technology/tech/java/newto/introejb.htm or Java World: (has more code examples) http://www.javaworld.com/javaworld/jw-08-2004/jw-0809-ejb.html

10. Fall 2008 http://www.cis.ksu.edu 9 CIS 764 Database Systems Engineering Entity bean … bound to entity data, with unique key value; can contain multiple subitems.  where is the concept of a result set ? Session bean …  “session beans generally represent actions …” << bad OO ! “process entity” vs “data entity” Stateless … do not have internal state (  ) … rather: do not keep track of the callers state ! Stateful …..maintains the conversation state across multiple method invocations (e.g. a shopping cart) Beans have an associated deployment descriptor Beans have own QL … “OO version of sql “

11. Fall 2008 http://www.cis.ksu.edu 10 CIS 764 Database Systems Engineering EJB annotations http://www.fnogol.de/archives/2005/05/13/ejb-30-annotations-cheat-sheet/

12. Fall 2008 http://www.cis.ksu.edu 11 CIS 764 Database Systems Engineering

13. Fall 2008 http://www.cis.ksu.edu 12 CIS 764 Database Systems Engineering import javax.ejb.Stateless.*; @Stateless(name="CalculateEJB") public class CalculateEJBBean implements CalculateEJB { int value = 0; public String incrementValue() { value++; return "value incremented by 1"; } }

14. Fall 2008 http://www.cis.ksu.edu 13 CIS 764 Database Systems Engineering import javax.persistence.*; import java.util.ArrayList; import java.util.Collection; @Entity @Table(name = "EMPLOYEES") public class Employee implements java.io.Serializable { private int empId; private String eName; private double sal; @Id @Column(name="EMPNO", primaryKey=true) /* getters and setters here … see next slide }

15. Fall 2008 http://www.cis.ksu.edu 14 CIS 764 Database Systems Engineering public int getEmpId( ) { return empId; } public void setEmpId(int empId) { this.empId = empId; } public String getEname( ) { return eName; } public void setEname(String eName) { this.eName = eName; } public double getSal( ) { return sal; } public void setSal(double sal) { this.sal = sal; } public String toString() { StringBuffer buf = new StringBuffer(); buf.append("Class:").append(this.getClass(). getName()).append(" :: ").append(" empId:").append(getEmpId()). append(" ename:").append(getEname()).append("sal:").append(getSal()); return buf.toString(); } ??? Why the toString method <<<<<<<<<<<<<<<< ??? Why ArrayList and Collection

16. Fall 2008 http://www.cis.ksu.edu 15 CIS 764 Database Systems Engineering import javax.naming.Context; import javax.naming.InitialContext; public class CalculateejbClient { public static void main(String [] args) { Context context = new InitialContext(); CalculateEJB myejb = (CalculateEJB)context.lookup("java:comp/env/ejb/CalculateEJB"); myejb.incrementValue(); } } ??? Where does this “client” run ??

17. Fall 2008 http://www.cis.ksu.edu 16 CIS 764 Database Systems Engineering An OQL Resources http://www.oracle.com/technology/sample_code/tutorials/fbs/eql/toc.htm http://publib.boulder.ibm.com/infocenter/tivihelp/v8r1/index.jsp?topic=/com.ibm.netc ool_precision.doc/pr35se/xF1118340.html http://publib.boulder.ibm.com/infocenter/tivihelp/v8r1/index.jsp?topic=/com.ibm.netc ool_precision.doc/pr35se/xF1118340.html

18. Fall 2008 http://www.cis.ksu.edu 17 CIS 764 Database Systems Engineering Homework: Oracle “EJB3 Simple Tutorial” http://www.oracle.com/technology/obe/obe1013jdev/10131/10131_ejb_30/ejb_ 30.htm http://www.oracle.com/technology/obe/obe1013jdev/10131/10131_ejb_30/ejb_ 30.htm Do an “in essence” version for the PO DB. (e.g. … not the DB in the tutorial, do not need to implements all of the operations) Note: This is not a web app. The client has remote access to the bean. The client does just text output. Post snapshots in JDev, running the client, link to code

19. Fall 2008 http://www.cis.ksu.edu 18 CIS 764 Database Systems Engineering Note: Begin planning for future requirements: Group project: requirements, design, implementation, doc’s (weekly during 2ed half of semester) Contribute some tutorial content … ** “how to” ( more Oracle tutorials or dotNet, Ruby, Eclipse, etc.) ( expend previous tutorials or add new ones ) Submit some technical paper …. ** concepts … not “how to” ( 2.. 4 pages, w references, related to 764 topics ) Class presentation or either tutorial or paper: ** both require prior approval of topics.

20. Fall 2008 http://www.cis.ksu.edu 19 CIS 764 Database Systems Engineering end.