D Copyright © 2005, Oracle. All rights reserved. BMP Entity EJBs J2EE Connector Architecture

DCopyright © 2005, Oracle. All rights reserved.

BMP Entity EJBsJ2EE Connector Architecture

D-2 Copyright © 2005, Oracle. All rights reserved.

BMP Bean: Example

• The example in this lesson creates a BMP entity bean with the following components:

– Remote interface: JobsBMP– Home interface: JobsBMPHome– Bean class: JobsBMPBean– Primary key class: JobsBMPPK– Exception class: JobSalException– Deployment descriptor: ejb-jar.xml

• Client for the JobsBMP bean: JobsBMPClient


Remote Interface: JobsBMP

...public interface JobsBMP extends EJBObject { void incrMinSal(double amt) throws JobSalException, RemoteException; void incrMaxSal(double amt) throws RemoteException; String getJobTitle()throws RemoteException; void setJobTitle(String title)throws RemoteException; double getMinSal()throws RemoteException; void setMinSal(double amt)throws RemoteException; double getMaxSal()throws RemoteException; void setMaxSal(double amt)throws RemoteException; }


Home Interface: JobsBMPHome

...

public interface JobsBMPHome extends EJBHome

{

JobsBMP create() throws RemoteException, CreateException;

JobsBMP create(String id, String title, double minSal, double maxSal) throws CreateException,RemoteException;JobsBMP findByPrimaryKey(JobsBMPPK primKey) throws FinderException, RemoteException;Collection findByMaxSalLimit (double salLimit) throws FinderException, RemoteException;double getAvgMaxSal() throws JobSalException, RemoteException;

}


Primary Key Class: JobsBMPPK

import java.io.Serializable;

public class JobsBMPPK implements Serializable

{ public String jobId;public JobsBMPPK(String id) { this.jobId = id; }public boolean equals(Object job) {...}public int hashCode() { return super.hashCode(); }public String toString()

{ return jobId; }

}


User-Defined Exception: JobSalException

public class JobSalException extends Exception

{

public JobSalException(){ super(); }

public JobSalException(Exception e)

{ super(e.toString()); }

public JobSalException(String s) { super(s); }

}


Bean Class: JobsBMPBean

...

public class JobsBMPBean implements EntityBean { public String id; public String jobTitle; public double maxSal; public double minSal; private Connection conn = null; private EntityContext context; private PreparedStatement ps = null; private ResultSet rset = null; public JobsBMPBean()

{ System.out.println("New bean instance created"); }

...



...public JobsBMPPK ejbCreate(String id, String title, double minSal, double maxSal) { try {

this.id = id; this.jobTitle = title; this.minSal = minSal; this.maxSal = maxSal; conn = getConnection(); ps = conn.prepareStatement("INSERT INTO jobs VALUES(?,?,?,?)"); ps.setString(1, id); ps.setString(2, jobTitle); ps.setDouble(3, minSal); ps.setDouble(4, maxSal); ps.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { closeConnection(); } return new JobsBMPPK(id);

}...


create() and ejbCreate()

Client

Home object

EJBobject

Entity Beaninstance

Table in database

create()

EJB Object

ejbCreate()

primary key

EJB Container

1 2

345



public void ejbPostCreate(String id, String title, double minSal, double maxSal)

{ } public JobsBMPPK ejbFindByPrimaryKey(JobsBMPPK primKey)

{ try { conn = getConnection(); ps = conn.prepareStatement( "SELECT job_id FROM jobs WHERE job_id = ?"); ps.setString(1, primKey.toString()); rset = ps.executeQuery(); if (!rset.next()) { throw new ObjectNotFoundException("no job with job ID " + primKey); } ps.close(); } catch (Exception e) { ... } finally { closeConnection(); }

return primKey; }



public void ejbActivate() { }public void ejbPassivate() { }public void setEntityContext(EntityContext ctx)

{ this.context = ctx; }public void unsetEntityContext()

{ this.context = null; }public void ejbRemove(){

JobsBMPPK jobId = (JobsBMPPK)context.getPrimaryKey();try { conn = getConnection(); ps = conn.prepareStatement("DELETE FROM jobs WHERE job_id = ?"); ps.setString(1, jobId.toString()); ps.executeUpdate();

} catch (Exception e1) {...}finally { closeConnection(); } }



public void ejbLoad() { JobsBMPPK key=(JobsBMPPK)context.getPrimaryKey();

this.id = key.jobId;try { conn = getConnection(); ps = conn.prepareStatement( "SELECT job_title,min_salary, max_salary " + "FROM jobs WHERE job_id = ? "); ps.setString(1, id); rset = ps.executeQuery(); rset.next();

jobTitle = rset.getString("job_title"); minSal = rset.getDouble("min_salary"); maxSal = rset.getDouble("max_salary"); } ...

}



public void ejbStore() {JobsBMPPK key= (JobsBMPPK)context.getPrimaryKey();String id = key.jobId; try {

conn = getConnection(); ps = conn.prepareStatement( "UPDATE jobs SET job_title=?, min_salary=?, max_salary=? WHERE job_id = ?"); ps.setString(1, jobTitle); ps.setDouble(2, minSal); ps.setDouble(3, maxSal); ps.setString(4, id); ps.executeUpdate();

} ... }



public void incrMinSal(double amt) throws JobSalException {

if ((minSal + amt) > maxSal) { throw new JobSalException ("You cannot

increase min salary to be more than " + maxSal);}

else { minSal += amt; } } public void incrMaxSal(double amt)

{ maxSal += amt; } public String getJobTitle()

{ return jobTitle; } public void setJobTitle(String title)

{ this.jobTitle = title; } public double getMinSal()

{ return minSal; }



public void setMinSal(double amt) { this.minSal = minSal; }public double getMaxSal() { return maxSal; }public void setMaxSal(double amt) { this.maxSal = maxSal; }private Connection getConnection() throws SQLException { DataSource ds=null; try { Context ctx = new InitialContext(); ds=(DataSource)ctx.lookup("java:comp/env/jdbc/hrDS"); } catch (NamingException e) { System.out.println("Could not get connection"); e.printStackTrace(); throw new SQLException(e.getMessage()); } return ds.getConnection(); }



private void closeConnection () { try { if (rset != null) rset.close();} catch (Exception e) {...} try { if (ps != null) ps.close();} catch (Exception e) {...} try { if (conn != null) conn.close(); } catch (Exception e) {...} }



public double ejbHomeGetAvgMaxSal()throws JobSalException { try {

conn = getConnection(); ps = conn.prepareStatement

("SELECT AVG(max_salary) as AvgMax FROM jobs"); rset = ps.executeQuery(); if (rset.next()) return rset.getDouble("AvgMax");

} catch (Exception e) { e.printStackTrace(); throw new JobSalException(); } finally { closeConnection(); } throw new JobSalException ("Error in the method"); }



public Collection ejbFindByMaxSalLimit(double salLimit) { Vector v = null;

try {v = new Vector();conn = getConnection();

ps = conn.prepareStatement ("SELECT job_id FROM jobs WHERE max_salary > ? "); ps.setDouble(1,salLimit); rset = ps.executeQuery();

while (rset.next()) { String id = rset.getString("job_id"); v.addElement(new JobsBMPPK(id));

} } catch (Exception e) {...} finally { closeConnection(); }

return v; }}


Deployment Descriptor

... <ejb-jar> <enterprise-beans> <entity>

<ejb-name>JobsBMP</ejb-name> <home> demos.JobsBMPHome</home> <remote>demos.JobsBMP</remote> <ejb-class>demos.JobsBMPBean</ejb-class> <persistence-type>Bean</persistence-type> <prim-key-class>demos.JobsBMPPK

</prim-key-class> <reentrant>False</reentrant><resource-ref> <res-ref-name>jdbc/hrDS</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Application</res-auth></resource-ref> </entity> ...


... </enterprise-beans> <assembly-descriptor><container-transaction><method>

<ejb-name>JobsBMP</ejb-name> <method-name>*</method-name>

</method> <trans-attribute>Required</trans-attribute>

</container-transaction> </assembly-descriptor></ejb-jar>

Deployment Descriptor


<?xml version="1.0" standalone='yes'?> ... <data-sources>

<data-source class="com.evermind.sql.DriverManagerDataSource" name="OracleDS" location="jdbc/OracleCoreDS" xa-location="jdbc/xa/OracleXADS" ejb-location="jdbc/hrDS"

connection-driver="oracle.jdbc.driver.OracleDriver"

url="jdbc:oracle:thin:@localhost:1521:orcl" username="hr" password="hr" inactivity-timeout="30" /> </data-sources>

Creating Data Source data-sources.xml


Client Class: JobsBMPClient

import javax.ejb.*;import java.rmi.RemoteException;import java.sql.*;import java.util.*;import javax.naming.*;public class JobsBMPClient { public static void main(String[] args) {

JobsBMP jobs = null; try {

Context context = getInitialContext(); JobsBMPHome jobsBMPHome = (JobsBMPHome) PortableRemoteObject.narrow

(context.lookup("JobsBMP"),JobsBMPHome.class); JobsBMP jobsBMP; jobsBMP = jobsBMPHome.create("job_dev", "Bean Developer", 3000, 5000);

...


Client Class: JobsBMPClient... jobsBMP.incrMinSal( 200.0 );System.out.println ("min_salary after incrementing

" + jobsBMP.getMinSal( ));jobsBMP.incrMaxSal( 600.0 );System.out.println ("max_salary after incrementing

" + jobsBMP.getMaxSal( ));System.out.println("printing job_title "+

jobsBMP.getJobTitle( ));Collection

col=jobsBMPHome.findByMaxSalLimit(15000); Iterator it = col.iterator(); while (it.hasNext()) {

JobsBMP jobSals = (JobsBMP)it.next();System.out.println(jobSals.getMaxSal());

} }catch(Throwable ex) {...} }

...


Overview of J2EE Connector Architecture

• The J2EE Connector Architecture (JCA) enables J2EE components to interact with Enterprise Information Systems (EISs) such as:– Enterprise resource planning (ERP)– Mainframe transaction processing– Databases and nonrelational systems, and so on

• JCA simplifies the integration of diverse EISs. Adherence to the JCA specification makes an EIS implementation portable across compliant J2EE servers.


OC4J J2EE Connector Architecture

Basic J2EE Connector Architecture:

OC4J

J2EE ApplicationComponent

ResourceAdapter

Enterprise Information

System

ApplicationContract

SystemContracts

(Quality ofService)


What Is a Resource Adapter?

It is a driver used by a client application to connect to a specific EIS.

• OC4J provides support for two J2EE 1.3 types:– A stand-alone resource adapter, which is found in a

Resource Adapter Archive (RAR) file for use by all deployed applications

– An embedded resource adapter, which is bundled in an EAR file for a specific enterprise application

• Examples of resource adapters:– JDBC or SQL for Java (SQLJ) drivers for database

connections– ERP adapter to connector a specific ERP


Resource Adapter Deployment Descriptors

OC4J provides the following deployment descriptors for resource adapters:

• ra.xml: A standard J2EE deployment descriptor for developing an adapter

• oc4j-ra.xml: Contains deployment configurations for deploying an adapter to OC4J

• oc4j-connectors.xml

• One oc4j-connectors.xml file: Contains a list of stand-alone resource adapters deployed. It is located in the ORACLEAS_HOME/j2ee/home/config directory.


Deploying Stand-Alone Resource Adapters

When deploying stand-alone adapters:

• Give the resource adapter a unique name, to simplify future operations such as removal of a deployed resource adapter

• Deploy in one of the following two ways:– Using the Admin command-line tool (admin.jar)– Manually through directory manipulation, by

expanding the .rar file contents into a user-specified directory name <connector-name> below the ORACLEAS_HOME/j2ee/home/<connector directory> (which defaults to ORACLEAS_HOME/j2ee/home/connectors)


Deploying Embedded Resource Adapters

• Embedded resource adapters are packaged and deployed inside an Enterprise Application Archive (EAR) file.

• Each application (from an EAR file) has one oc4j-connectors.xml file.

• The application oc4j-connectors.xml file lists all the resource adapters deployed in the EAR file.

• The oc4j-connectors.xml file is automatically generated if not already included in the EAR file.


Common Client Interface (CCI) API

CCI is defined by the J2EE Connector Architecture specification as:

• A set of interfaces and classes to allow a J2EE component to perform data access operations with an EIS

• Main interfaces and classes are:– ConnectionFactory– Connection– Interaction– RecordFactory– Record

(Use Sun’s Java J2EE Tutorial for more information.)

Documents

D Copyright © 2005, Oracle. All rights reserved. BMP Entity EJBs J2EE Connector Architecture