EJB3 + JPA on OC4J with Client

Let’s use the previous JPA sample in an EJB. We start creating a datasource on the OC4J container. Then we create the entities again. After this we use the entities in a Stateless EJB which we will deploy to OC4J 11g. Finally we create a stand-alone client which calls the EJB.

We start with the creation of the datasource. We need a ConnectionPool.

java -jar $OC4J_ADMIN/j2ee/home/admin_client.jar deployer:oc4j:localhost oc4jadmin welcome -CreateJDBCConnectionPool -applicationName default -name HrConnectionPool -factoryClass oracle.jdbc.pool.OracleDataSource -user hr -password hr -url jdbc:oracle:thin:@localhost:1521:orcl

Test the connectionpool:

java -jar $OC4J_ADMIN/j2ee/home/admin_client.jar deployer:oc4j:localhost oc4jadmin welcome
-testConnectionPool -connectionPoolName HrConnectionPool -sqlStatement “select
* from dual” And the datasource:

java -jar $OC4J_ADMIN/j2ee/home/admin_client.jar deployer:oc4j:localhost oc4jadmin welcome -createManagedDataSource -applicationName default -dataSourceName HrDataSource -jndiLocation jdbc/HrDataSource -connectionPoolName HrConnectionPool

After this we create the entities:

/home/broersa/work/CountryApp/CountryJPAEJB/src/com/bekijkhet/entity/Country.java:

package com.bekijkhet.entity;

import java.io.Serializable;
import javax.persistence.*;

@Entity
@Table(name="COUNTRIES")
public class Country implements Serializable {
        private String id;
        private String name;
        private Region region;

        @Id
        @Column(name="COUNTRY_ID")
        public String getId() {
                return id;
        }

        public void setId(String id) {
                this.id = id;
        }

        @Column(name="COUNTRY_NAME")
        public String getName() {
                return name;
        }

        public void setName(String name) {
                this.name = name;
        }

        @ManyToOne(cascade={CascadeType.ALL})
        @JoinColumn(name="REGION_ID",nullable=false)
        public Region getRegion() {
                return region;
        }

        public void setRegion(Region region) {
                this.region = region;
        }
}

/home/broersa/work/CountryApp/CountryJPAEJB/src/com/bekijkhet/entity/Region.java

package com.bekijkhet.entity;

import java.io.Serializable;
import javax.persistence.*;
import static javax.persistence.CascadeType.*;
import static javax.persistence.FetchType.*;

import java.util.List;
import java.util.ArrayList;

@Entity
@Table(name="REGIONS")
public class Region implements Serializable {
        private int id;
        private String name;
        private List<Country> countries = new ArrayList<Country>();;

        @Id
        @Column(name="REGION_ID")
        public int getId() {
                return id;
        }

        public void setId(int id) {
                this.id = id;
        }

        @Column(name="REGION_NAME")
        public String getName() {
                return name;
        }

        public void setName(String name) {
                this.name = name;
        }

        @OneToMany(fetch=FetchType.EAGER, cascade={CascadeType.ALL}, mappedBy="region")
        public List<Country> getCountries() {
                return countries;
        }

        public void setCountries(List<Country> newValue) {
                this.countries = newValue;
        }
}

The EJB:/home/broersa/work/CountryApp/CountryJPAEJB/src/com/bekijkhet/country/CountryEJBLocal.java:

package com.bekijkhet.country;

import com.bekijkhet.entity.*;
import java.util.List;

public interface CountryEJBLocal {
  public List<Country> getCountriesByRegion(String region);
  public Region getRegionByCountry(String country);
}

/home/broersa/work/CountryApp/CountryJPAEJB/src/com/bekijkhet/country/CountryEJB.java:

package com.bekijkhet.country;
import java.util.List;
import com.bekijkhet.entity.*;
public interface CountryEJB {
  public List<Country> getCountriesByRegion(String region);
  public Region getRegionByCountry(String country);
  public void addorchangeCountry(Country country) ;
  public void addorchangeRegion(Region region) ;
  public void removeCountry(Country country) ;
  public void removeRegion(Region region) ;
  public List<Region> getAllRegions() ;
  public List<Country> getAllCountries();
}

/home/broersa/work/CountryApp/CountryJPAEJB/src/com/bekijkhet/country/CountryEJBBean.java

package com.bekijkhet.country;
import javax.ejb.Stateless;
import javax.ejb.Remote;
import javax.ejb.Local;

import java.util.List;
import com.bekijkhet.entity.*;
import javax.persistence.*;

@Stateless
@Remote(CountryEJB.class)
@Local(CountryEJBLocal.class)
public class CountryEJBBean implements CountryEJB,CountryEJBLocal {
  @PersistenceContext
  EntityManager em;

  public List<Country> getCountriesByRegion(String region) {
    Query q = em.createQuery("select r from Region r where r.name = :name");
    q.setParameter("name",region);
    Region r = (Region) q.getSingleResult();
//    r.getCountries().size();  // get the LAZY relation
    return r.getCountries();
  }

  public Region getRegionByCountry(String country) {
    Query q = em.createQuery("select c from Country c where c.name = :name");
    q.setParameter("name",country);
    Country c = (Country) q.getSingleResult();
    return c.getRegion();
  }

  public void addorchangeCountry(Country country) {
    em.persist(country);
  }

  public void addorchangeRegion(Region region) {
    em.persist(region);
  }

  public void removeCountry(Country country) {
    Country c = em.merge(country);
    em.remove(c);
  }

  public void removeRegion(Region region) {
    Region r = em.merge(region);
    em.remove(r);
  }

  public List<Region> getAllRegions() {
    Query q = em.createQuery("select r from Region r");
    List<Region> l = q.getResultList();
    return l;
  }

  public List<Country> getAllCountries() {
    Query q = em.createQuery("select c from Country c");
    List<Country> l = q.getResultList();
    return l;
  }
}

We need a persistence descriptor : /home/broersa/work/CountryApp/CountryJPAEJB/src/META-INF/persistence.xml:

<persistence>
  <persistence-unit name="MyPU">
    <jta-data-source>jdbc/HrDataSource</jta-data-source>
  </persistence-unit>
</persistence>

We need the build file:/home/broersa/work/CountryApp/CountryJPAEJB/build.xml:

<project name="CountryJPAEJB" default="dist" basedir=".">
    <description>
        simple example build file
    </description>
  <!-- set global properties for this build -->
  <property name="src" location="src"/>
  <property name="build" location="build"/>
  <property name="dist"  location="dist"/>

 <path id="files-classpath">
     <!--fileset dir="$HOME/oc4j_client_11110_preview/j2ee/home/lib" >
         <include name="persistence.jar"/>
     </fileset-->
     <pathelement location="/home/broersa/oc4j_client_11110_preview/j2ee/home/lib/persistence.jar"/>
     <pathelement location="/home/broersa/oc4j_client_11110_preview/j2ee/home/lib/ejb.jar"/>
 </path>

  <target name="init">
    <!-- Create the time stamp -->
    <tstamp/>
    <!-- Create the build directory structure used by compile -->
    <mkdir dir="${build}"/>
  </target>

  <target name="compile" depends="init"
        description="compile the source " >
    <!-- Compile the java code from ${src} into ${build} -->
    <javac srcdir="${src}" destdir="${build}">
      <classpath refid="files-classpath" />
    </javac>
  </target>

  <target name="dist" depends="compile"
        description="generate the distribution" >
    <!-- Create the distribution directory -->
    <mkdir dir="${dist}"/>
    <copy todir="${build}/META-INF">
                        <fileset dir="src/META-INF">
                                <include name="*" />
                        </fileset>
                   </copy>

    <!-- Put everything in ${build} into the MyProject-${DSTAMP}.jar file -->
    <jar jarfile="${dist}/CountryBean.jar" basedir="${build}"/>
  </target>

  <target name="clean"
        description="clean up" >
    <!-- Delete the ${build} and ${dist} directory trees -->
    <delete dir="${build}"/>
    <delete dir="${dist}"/>
  </target>
</project>

We can build and deploy the EJB:type “ant” to build the EJB.use the next command to deploy the ejb:

java -jar $OC4J_ADMIN/j2ee/home/admin_client.jar deployer:oc4j:localhost oc4jadmin welcome -deploy -file $HOME/work/CountryApp/CountryJPAEJB/dist/CountryBean.jar -deploymentName CountryBean

Now this is done we can create the client:

/home/broersa/work/CountryApp/CountryClient/com/bekijkhet/CountryClient.java:

package com.bekijkhet;
import javax.naming.*;
import com.bekijkhet.country.CountryEJB;
import com.bekijkhet.entity.*;
import java.util.Properties;
import java.util.List;

public class CountryClient {
  public static void main(String[] args) {
    try {
      Properties props = new Properties();
      props.put("java.naming.factory.initial","com.evermind.server.ApplicationClientInitialContextFactory");
      props.put("java.naming.provider.url","ormi://localhost/CountryBean");
      props.put("java.naming.security.principal","oc4jadmin");
      props.put("java.naming.security.credentials","welcome");
      InitialContext ctx = new InitialContext(props);
      CountryEJB h = (CountryEJB)ctx.lookup("CountryEJBBean");

      System.out.println("The Netherlands has region: " + h.getRegionByCountry("Netherlands").getName());
      List<Country> l1 = h.getCountriesByRegion("Europe");
      System.out.println("Europe has the following countries:");
      for (Country c : l1) {
       System.out.println("  " + c.getName());
      }
      System.out.println("All regions:");
      List<Region> l2 = h.getAllRegions();
      for (Region r : l2) {
       System.out.println("  " + r.getName());
      }
      System.out.println("All countries:");
      List<Country> l3 = h.getAllCountries();
      for (Country c2 : l3) {
       System.out.println("  " + c2.getName() + " - " + c2.getRegion().getName());
      }

      Region r3 = new Region();
      r3.setName("MyRegion1");
      r3.setId(1001);
      Country c3 = new Country();
      c3.setName("MyCountry1");
      c3.setId("31");
      c3.setRegion(r3);
      r3.getCountries().add(c3);
      h.addorchangeCountry(c3);

      Region r4 = new Region();
      r4.setName("MyRegion2");
      r4.setId(1002);
      Country c4 = new Country();
      c4.setName("MyCountry2");
      c4.setId("32");
      c4.setRegion(r4);
      r4.getCountries().add(c4);
      h.addorchangeRegion(r4);

      System.out.println("All regions:");
      List<Region> l5 = h.getAllRegions();
      for (Region r5 : l5) {
       System.out.println("  " + r5.getName());
      }
      System.out.println("All countries:");
      List<Country> l6 = h.getAllCountries();
      for (Country c6 : l6) {
       System.out.println("  " + c6.getName() + " - " + c6.getRegion().getName());
      }
    }
    catch (Exception e) {
      System.out.println(e);
      e.printStackTrace();
    }
  }
}

/home/broersa/work/CountryApp/CountryClient/com/bekijkhet/META-INF/application-client.xml:

<?xml version="1.0" encoding="UTF-8"?>
<application-client version="1.4" xmlns="http://java.sun.com/xml/ns/j2ee"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
                http://java.sun.com/xml/ns/j2ee/application-client_1_4.xsd">
  <display-name>CountryClient</display-name>
  <description>test</description>
</application-client>

Compile the client:javac -cp $OC4J_HOME/j2ee/home/oc4jclient.jar:/home/broersa/work/CountryApp/CountryJPAEJB/dist/CountryBean.jar:. -d . CountryClient.javaAnd test the client:java -cp $OC4J_HOME/j2ee/home/oc4jclient.jar:/home/broersa/work/CountryApp/CountryJPAEJB/dist/CountryBean.jar:. com.bekijkhet.CountryClient

The Netherlands has region: Europe
Europe has the following countries:
Belgium
Switzerland
Germany
Denmark
France
Italy
Netherlands
United Kingdom
All regions:
Europe
Americas
Asia
Middle East and Africa
All countries:
Argentina – Americas
Australia – Asia
Belgium – Europe
Brazil – Americas
Canada – Americas
Switzerland – Europe
China – Asia
Germany – Europe
Denmark – Europe
Egypt – Middle East and Africa
France – Europe
HongKong – Asia
Israel – Middle East and Africa
India – Asia
Italy – Europe
Japan – Asia
Kuwait – Middle East and Africa
Mexico – Americas
Nigeria – Middle East and Africa
Netherlands – Europe
Singapore – Asia
United Kingdom – Europe
United States of America – Americas
Zambia – Middle East and Africa
Zimbabwe – Middle East and Africa
All regions:
Europe
Americas
Asia
Middle East and Africa
MyRegion1
MyRegion2
All countries:
MyCountry1 – MyRegion1
MyCountry2 – MyRegion2
Argentina – Americas
Australia – Asia
Belgium – Europe
Brazil – Americas
Canada – Americas
Switzerland – Europe
China – Asia
Germany – Europe
Denmark – Europe
Egypt – Middle East and Africa
France – Europe
HongKong – Asia
Israel – Middle East and Africa
India – Asia
Italy – Europe
Japan – Asia
Kuwait – Middle East and Africa
Mexico – Americas
Nigeria – Middle East and Africa
Netherlands – Europe
Singapore – Asia
United Kingdom – Europe
United States of America – Americas
Zambia – Middle East and Africa
Zimbabwe – Middle East and Africa

Stand Alone JPA client using Oracle 11g Database HR schema

In this sample we will create a stand alone java app which uses the JPA (Toplink) api to connect to the HR sample schema in a Oracle database.

The hr schema must be unlocked and database must be accessible via the network.

We will start with the persistence.xml file.

/home/broersa/work/CountryApp/CountryJPA/build/META-INF/persistence.xml

<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">
<persistence-unit name="default">
    <provider>
        oracle.toplink.essentials.PersistenceProvider
    </provider>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
        <property name="toplink.logging.level" value="INFO"/>
        <property name="toplink.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
        <property name="toplink.jdbc.url" value="jdbc:oracle:thin:centos.bekijkhet.com:l521:orcl"/>
        <property name="toplink.jdbc.password" value="hr"/>
        <property name="toplink.jdbc.user" value="hr"/>
    </properties>
</persistence-unit>
</persistence>

After this the entities which represent the database objects. I choose the regions and countries tables.

/home/broersa/work/CountryApp/CountryJPA/src/com/bekijkhet/entity/Region.java

package com.bekijkhet.entity;

import java.io.Serializable;
import javax.persistence.*;
import static javax.persistence.CascadeType.*;

import java.util.List;
import java.util.ArrayList;

@Entity
@Table(name="REGIONS")
public class Region implements Serializable {
        private int id;
        private String name;
        private List<Country> countries = new ArrayList<Country>();;

        @Id
        @Column(name="REGION_ID")
        public int getId() {
                return id;
        }

        public void setId(int id) {
                this.id = id;
        }

        @Column(name="REGION_NAME")
        public String getName() {
                return name;
        }

        public void setName(String name) {
                this.name = name;
        }

        @OneToMany(cascade={CascadeType.ALL}, mappedBy="region")
        public List<Country> getCountries() {
                return countries;
        }

        public void setCountries(List<Country> newValue) {
                this.countries = newValue;
        }
}

/home/broersa/work/CountryApp/CountryJPA/src/com/bekijkhet/entity/Country.java

package com.bekijkhet.entity;

import java.io.Serializable;
import javax.persistence.*;

@Entity
@Table(name="COUNTRIES")
public class Country implements Serializable {
        private String id;
        private String name;
        private Region region;

        @Id
        @Column(name="COUNTRY_ID")
        public String getId() {
                return id;
        }

        public void setId(String id) {
                this.id = id;
        }

        @Column(name="COUNTRY_NAME")
        public String getName() {
                return name;
        }

        public void setName(String name) {
                this.name = name;
        }

        @ManyToOne()
        @JoinColumn(name="REGION_ID",nullable=false)
        public Region getRegion() {
                return region;
        }

        public void setRegion(Region region) {
                this.region = region;
        }
}

 Compile the entities:

cd /home/broersa/work/CountryApp/CountryJPA

javac -cp /home/broersa/oc4j_client_11110_preview/j2ee/home/lib/persistence.jar:build -d build src/com/bekijkhet/entity/*.java

After this the client app:

/home/broersa/work/CountryApp/CountryJPA/src/com/bekijkhet/client/Client.java:

package com.bekijkhet.client;

import javax.persistence.EntityManager;
import javax.persistence.Persistence;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Query;

import java.util.List;

import com.bekijkhet.entity.*;

public class Client {
  private static EntityManagerFactory emf;
  private static EntityManager em;

  public static void main(String[] args) {

    emf = Persistence.createEntityManagerFactory("default");
    em = emf.createEntityManager();

    // Find a country with region
    Query q1 = em.createQuery("select c from Country c where c.id = :id");
    q1.setParameter("id","NL");
    Country c1 = (Country) q1.getSingleResult();
    System.out.println(c1.getName() + " - " + c1.getRegion().getName());

    // Find a region with countries
    Query q2 = em.createQuery("select r from Region r where r.id = :id");
    q2.setParameter("id",1);
    Region r2 = (Region) q2.getSingleResult();
    System.out.println(r2.getName());
    List<Country> l2 = r2.getCountries();
    for (Country c2 : l2) {
      System.out.println("  " + c2.getName());
    }

    // Add a region with two countries
    em.getTransaction().begin();
    Region r3 = new Region();
    r3.setId(1001);
    r3.setName("MyRegion1");
    Country c31 = new Country();
    c31.setId("31");
    c31.setName("MyCountry31");
    c31.setRegion(r3);
    r3.getCountries().add(c31);
    Country c32 = new Country();
    c32.setId("32");
    c32.setName("MyCountry32");
    c32.setRegion(r3);
    r3.getCountries().add(c32);

    em.persist(r3);
    em.getTransaction().commit();

    // List the added region with countries
    Query q4 = em.createQuery("select r from Region r where r.id = :id");
    q4.setParameter("id",1001);
    Region r4 = (Region) q4.getSingleResult();
    System.out.println(r4.getName());
    List<Country> l4 = r4.getCountries();
    for (Country c4 : l4) {
      System.out.println("  " + c4.getName());
    }

    // Change the country names
    em.getTransaction().begin();
    Query q5 = em.createQuery("select r from Region r where r.id = :id");
    q5.setParameter("id",1001);
    Region r5 = (Region) q5.getSingleResult();
    List<Country> l5 = r5.getCountries();
    for (Country c5 : l5) {
      c5.setName(c5.getName()+"-changed");
    }
    em.getTransaction().commit();

    // List the added region with countries
    Query q6 = em.createQuery("select r from Region r where r.id = :id");
    q6.setParameter("id",1001);
    Region r6 = (Region) q6.getSingleResult();
    System.out.println(r6.getName());
    List<Country> l6 = r6.getCountries();
    for (Country c6 : l6) {
      System.out.println("  " + c6.getName());
    }

    // Remove samples
    // Remove a single detail
    em.getTransaction().begin();
    Query q7 = em.createQuery("select r from Region r where r.id = :id");
    q7.setParameter("id",1001);
    Region r7 = (Region) q7.getSingleResult();
    System.out.println(r7.getName());
    List<Country> l7 = r7.getCountries();
    em.remove(l7.get(1));
    em.getTransaction().commit();

    // Remove samples
    // Remove the whole region
    em.getTransaction().begin();
    Query q8 = em.createQuery("select r from Region r where r.id = :id");
    q8.setParameter("id",1001);
    Region r8 = (Region) q8.getSingleResult();
    System.out.println(r8.getName());
    em.remove(r8);
    em.getTransaction().commit();

    em.close();

  }
}

compile and run:

cd /home/broersa/work/CountryApp/CountryJPA

javac -cp /home/broersa/oc4j_client_11110_preview/j2ee/home/lib/persistence.jar:build -d build src/com/bekijkhet/client/*.java

java -cp /home/broersa/oc4j_client_11110_preview/j2ee/home/lib/persistence.jar:/home/broersa/toplink_11.1.1.0_071214_preview-3/lib/java/api/toplink.jar:/home/broersa/myclasses/ojdbc6.jar:build -javaagent:/home/broersa/toplink_11.1.1.0_071214_preview-3/lib/java/internal/toplink-essentials-agent.jar com.bekijkhet.client.Client

[TopLink Info]: 2008.01.28 08:09:38.718–ServerSession(9519074)–TopLink, version: Oracle TopLink Essentials – 2.0 (Build SNAPSHOT (06/04/2007))
[TopLink Info]: 2008.01.28 08:09:41.744–ServerSession(9519074)–file:/home/broersa/work/CountryApp/CountryJPA/build/-default login successful
Netherlands – Europe
Europe
Belgium
Switzerland
Germany
Denmark
France
Italy
Netherlands
United Kingdom
MyRegion1
MyCountry31
MyCountry32
MyRegion1
MyCountry31-changed
MyCountry32-changed
MyRegion1
MyRegion1