BMP Entity EJBs J2EE Connector Architecture

BMP Entity EJBsJ2EE Connector Architecture

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"); } ...

Bean Class: JobsBMPBean ... public JobsBMPPKejbCreate(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); } ...

Home object EJBobject create() and ejbCreate() EJB Container 1 2 ejbCreate() create() Entity Beaninstance primary key EJB Object 5 4 3 Client Table in database

Bean Class: JobsBMPBean 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; }

Bean Class: JobsBMPBean public void ejbActivate() { }public void ejbPassivate() { }public void setEntityContext(EntityContext ctx) { this.context = ctx; }public voidunsetEntityContext() { 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(); } }

Bean Class: JobsBMPBean 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"); } ... }

Bean Class: JobsBMPBean 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(); } ... }

Bean Class: JobsBMPBean • 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; }

Bean Class: JobsBMPBean 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(); }

Bean Class: JobsBMPBean 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) {...} }

Bean Class: JobsBMPBean 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"); • }

Bean Class: JobsBMPBean • 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> ...

Deployment Descriptor ... </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>

Creating Data Source data-sources.xml <?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>

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: ApplicationContract OC4J ResourceAdapter SystemContracts (Quality ofService) Enterprise Information System J2EE ApplicationComponent

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.)

BMP Entity EJBs J2EE Connector Architecture