[jboss-user] [J2EE Design Patterns] - EJB3.0-Relations one-to-many
dasariprasad
do-not-reply at jboss.com
Sat Sep 2 23:07:43 EDT 2006
Dear colleague,
I had developed one one to many relation(bi-directional) as a part of learning having two entity beans and one Stateful session facade for them. i could able to create entity beans and add a mny bean to the collection of one-side bean.but later when i search for individual beans ,it is showing errors and returning a null.In the server log file ,it is getting the information but not able to return to the client.The code is
one side Entity
package cmp3rels;
import javax.persistence.*;
import javax.ejb.*;
import java.util.Set;
import java.util.HashSet;
@Entity()
@Table(name="AREA")
@NamedQuery(name="plain.areas ", query="select a from Area a ")
public class Area implements java.io.Serializable
{
Integer id;
String areaName;
int population;
Set bazars = new HashSet();
@Id
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
this.id = id;
}
@Column(name="AREA_NAME" ,nullable=false)
public String getAreaName()
{
return areaName;
}
public void setAreaName(String newAreaName)
{
areaName = newAreaName;
}
@Column
public int getPopulation()
{
return population;
}
public void setPopulation(int newPopulation)
{
population = newPopulation;
}
@OneToMany(cascade={CascadeType.ALL}, fetch=FetchType.EAGER, mappedBy="area")
@JoinColumn(name = "AREA_ID")
public Set getBazars()
{
return bazars;
}
public void setBazars(Set newBazars)
{
bazars = newBazars;
}
public String toString()
{
StringBuffer sb = new StringBuffer();
sb.append("Id:"+id);
sb.append("\nArea-Name:"+areaName);
sb.append("\nPopulation:"+population);
sb.append("\nbazars:"+bazars+"\n");
return sb.toString();
}
}
............................................................................................................
many-side entity
package cmp3rels;
import javax.persistence.*;
import javax.ejb.*;
@Entity()
@Table(name="BAZAR")
@NamedQuery(name="plain.bazars", query="select b from Bazar b ")
public class Bazar implements java.io.Serializable
{
Integer id;
String bazarName;
double turnover;
Area area;
@Id
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
this.id = id;
}
@Column(name="BAZAR_NAME" ,nullable=false)
public String getBazarName()
{
return bazarName;
}
public void setBazarName(String newBazarName)
{
bazarName = newBazarName;
}
@Column
public double getTurnover()
{
return turnover;
}
public void setTurnover(double newTurnover)
{
turnover = newTurnover;
}
@ManyToOne(cascade={CascadeType.ALL}, fetch=FetchType.EAGER)
@JoinColumn(name="AREA_ID" )
public Area getArea()
{
return area;
}
public void setArea(Area newArea)
{
area = newArea;
}
public String toString()
{
StringBuffer sb = new StringBuffer();
sb.append("Id: "+id);
sb.append("\nArea-Name: "+bazarName);
sb.append("\nTurnover: "+turnover);
sb.append("\nArea: "+area+"\n");
return sb.toString();
}
}
........................................................................................................
stateful facade is
interface
package cmp3rels;
import java.util.*;
import javax.ejb.Remote;
@Remote
public interface AreaSess
{
public boolean createArea(int id, String areaName, int population);
public boolean addBazarToArea(int areaCode, int bazarCode);
public boolean assignBazars(int areaCode , Set bazars);
public String getAreaInfo(Integer areaCode);
public boolean createBazar(int id, String bazarName, double turnover);
public Bazar getCodeBazar(Integer bazarCode);
public Area getCodeArea(Integer areaCode);
public Area getBazarArea(Bazar bazar);
public Area newArea(int id, String areaName, int population);
public Bazar newBazar(int id, String bazarName, double tover);
}
package cmp3rels;
import javax.ejb.Stateful;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceContextType;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Query;
import org.jboss.ejb3.entity.*;
import java.util.Set;
import java.util.HashSet;
import java.util.List;
@Stateful
public class AreaSessBean implements AreaSess,java.io.Serializable
{
@PersistenceContext(unitName="mydb", type=PersistenceContextType.EXTENDED)
private EntityManager em;
EntityTransaction trans;
private Area area;
private Bazar bazar;
public boolean createArea(int id, String areaName, int population)
{
boolean ret = false;
try
{
Area area = new Area();
area.setId(new Integer(id));
area.setAreaName(areaName);
area.setPopulation(population);
em.persist(area);
ret = true;
}
catch(Exception e)
{
e.printStackTrace(System.out);
}
return ret;
}
public boolean addBazarToArea(int areaCode, int bazarCode)
{
boolean ret = false;
Area area = null;
Bazar bazar = null;
Set bazars = null ;
try
{
area =(Area)em.find(Area.class,new Integer(areaCode));
System.out.println(area);
bazar =(Bazar)em.find(Bazar.class,new Integer(bazarCode));
if(area != null )
{
bazar.setArea(area);
bazars = area.getBazars();
bazars.add(bazar);
em.merge(area);
em.merge(bazar);
ret = true;
}
}
catch(Exception e)
{
e.printStackTrace(System.out);
}
return ret;
}
public Area getCodeArea(Integer areaCode)
{
Area ret = null;
try
{
System.out.println("param is:"+areaCode);
ret = (Area)em.getReference(Area.class, areaCode);
em.flush();
}
catch(Exception e)
{
StackTraceElement[] stck = e.getStackTrace();
System.out.println("1....:"+stck.length);
for(StackTraceElement elem : stck)
{
System.out.println(elem);
}
}
System.out.println("area is:"+ret);
return ret;
}
public Bazar getCodeBazar(Integer bazarCode)
{
Bazar ret = null;
try
{
System.out.println("param is :"+bazarCode);
ret = (Bazar)em.getReference(Bazar.class,bazarCode);
}
catch(Exception e)
{
StackTraceElement[] stck = e.getStackTrace();
System.out.println("1....:"+stck.length);
for(StackTraceElement elem : stck)
{
System.out.println(elem);
}
}
System.out.println("1....:"+ret);
return ret;
}
public boolean assignBazars(int areaCode , Set bazs)
{
boolean ret = false;
Area area = null;
Set bazars = null ;
try
{
area = (Area)em.find(cmp3rels.Area.class,new Integer(areaCode));
if(area != null )
{
bazars = area.getBazars();
bazars.clear();
bazars.addAll(bazs);
for(Bazar bz : bazs)
{
bz.setArea(area);
}
ret = true;
}
}
catch(Exception e)
{
e.printStackTrace(System.out);
}
return ret;
}
/* public String getAreaInfo(Integer areaCode)
{
String ret = "Not Available";
Area area = null;
String qryStr = "select Object(ar) from Area ar where ar.id=:d";
System.out.println("...."+areaCode);
try
{
Query qry = em.createQuery(qryStr);
qry.setParameter("d",areaCode);
System.out.println(qry);
List li = qry.getResultList();
if(li.size()>0 )
{
area = (Area)li.get(0);
ret = area.toString();
}
}
catch(Exception e)
{
StackTraceElement[] stck = e.getStackTrace();
System.out.println("1....:"+stck.length);
for(StackTraceElement elem : stck)
{
System.out.println(elem);
}
}
return ret;
}*/
public String getAreaInfo(Integer areaCode)
{
String ret = "Not Available";
Area area = null;
try
{
area =(Area)em.getReference(Area.class,areaCode);
if(area != null )
{
ret = area.toString();
}
}
catch(Exception e)
{
StackTraceElement[] stck = e.getStackTrace();
System.out.println("1....:"+stck.length);
for(StackTraceElement elem : stck)
{
System.out.println(elem);
}
}
return ret;
}
public boolean createBazar(int id, String bazarName, double turnover)
{
boolean ret = false;
try
{
Bazar bazar = new Bazar();
bazar.setId(new Integer(id));
bazar.setBazarName(bazarName);
bazar.setTurnover(turnover);
em.persist(bazar);
ret = true;
}
catch(Exception e)
{
e.printStackTrace(System.out);
}
return ret;
}
public Area getBazarArea(Bazar bazar1)
{
System.out.println("...."+em.isOpen());
String qryStr = " select ar from Area ar ,in (ar.bazars) brs " +
" where :b1 member of brs ";
Area area = null;
Bazar bazar = null;
try
{
Query qry = em.createQuery(qryStr);
qry.setParameter("b1",bazar1);
List li = qry.getResultList();
area = (Area)li.get(0);
}
catch(Exception e)
{
e.printStackTrace(System.out);
}
return area;
}
public Area newArea(int id, String areaName, int population)
{
Area ret = null;
try
{
Area area = new Area();
area.setId(new Integer(id));
area.setAreaName(areaName);
area.setPopulation(population);
em.persist(area);
ret = area;
}
catch(Exception e)
{
e.printStackTrace(System.out);
}
return ret;
}
public Bazar newBazar(int id, String bazarName, double tover)
{
Bazar ret = null;
try
{
Bazar bazar = new Bazar();
bazar.setId(new Integer(id));
bazar.setBazarName(bazarName);
bazar.setTurnover(tover);
em.persist(bazar);
ret = bazar;
}
catch(Exception e)
{
e.printStackTrace(System.out);
}
return ret;
}
}
...................................................................................................
working client class is
package cmp3rels;
import javax.ejb.*;
import javax.naming.*;
import javax.rmi.*;
import java.util.*;
import org.apache.log4j.*;
public class NewRel3Client
{
static Logger logger;
public static InitialContext getInitialContext()
{
Properties props=new Properties();
InitialContext jndiCtx=null;
try
{
props.put(Context.INITIAL_CONTEXT_FACTORY,"org.jnp.interfaces.NamingContextFactory");
props.put(Context.PROVIDER_URL,"jnp://localhost");
props.put(Context.STATE_FACTORIES,"org.jboss.naming:org.jnp.interfaces");
jndiCtx=new InitialContext(props);
}
catch(Exception ex)
{}
return jndiCtx;
}
public static void main(String args[])throws java.io.IOException
{
int[] areaIds = {1000,1005,1010};
String[] areas = {"Guindy","Tambaram","Mudichur"};
int[] pops = {490000,260000,95000};
int[] bazarIds = {100,105,110};
String bazars[] = {"Super-Special","Variety-Mart","Needs-Market"};
double tovers[] = {239879.30,199234.30,61439.30};
boolean created = false;
logger = Logger.getRootLogger();
logger.addAppender(new FileAppender(new HTMLLayout(),
"mylog1.log",true));
System.out.println("\nBegin New-EJB3-Rels-Client...\n");
try
{
InitialContext ctx=getInitialContext();
AreaSess sess =
(AreaSess)ctx.lookup("AreaSessBean/remote");
System.out.println("\nGot jndi named object..\n");
for(int i=0;i<3;i++)
{
created = sess.createArea(areaIds,areas,pops);
System.out.println("\nStatement Area Created is...:"+created);
created = sess.createBazar(bazarIds,bazars,tovers);
System.out.println("\nStatement Bazar Created is...:"+created);
}
Area area = null;
Bazar bazar = null;
for(int i=0;i<15;i+=5)
{
created = sess.addBazarToArea(1000+i,100+i);
System.out.println("bazar is added "+created);
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
............................................................................................................
not working class is
package cmp3rels;
import javax.ejb.*;
import javax.naming.*;
import javax.rmi.*;
import java.util.*;
import org.apache.log4j.*;
public class Rel3Client
{
static Logger logger;
public static InitialContext getInitialContext()
{
Properties props=new Properties();
InitialContext jndiCtx=null;
try
{
props.put(Context.INITIAL_CONTEXT_FACTORY,"org.jnp.interfaces.NamingContextFactory");
props.put(Context.PROVIDER_URL,"jnp://localhost:1099");
props.put(Context.URL_PKG_PREFIXES,"org.jboss.naming:org.jnp.interfaces");
jndiCtx=new InitialContext(props);
}
catch(Exception ex)
{}
return jndiCtx;
}
public static void main(String args[])throws java.io.IOException
{
boolean created = false;
logger = Logger.getRootLogger();
logger.addAppender(new FileAppender(new HTMLLayout(),
"mylog1.log",true));
System.out.println("\nBegin Rels3-Client...\n");
try
{
InitialContext ctx=getInitialContext();
Object obj = ctx.lookup("AreaSessBean/remote");
AreaSess sess = (AreaSess)PortableRemoteObject.narrow(obj,AreaSess.class);
System.out.println("\nGot jndi named object..\n");
Area area2 = sess.getCodeArea(new Integer(1000));
System.out.println("area...."+area2);
System.out.println("......::"+sess.getAreaInfo(new Integer(1000)));
Bazar bazar = sess.getCodeBazar(new Integer(105));
System.out.println("....:"+bazar);
Area area = sess.getBazarArea(bazar);
System.out.println("Area for bazar id-105 is: "+area);
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
}
}
i made one ant build file as
<?xml version="1.0" ?>
the oracle sql is
drop table bazar;
drop table area;
drop sequence area_seq;
drop sequence bazar_seq;
create sequence bazar_seq;
create sequence area_seq;
create table area(id number Constraint area_PK primary key,
area_name varchar2(20) not null,
population number);
create table bazar(id number Constraint bazar_PK primary key,
bazar_name varchar2(20) not null,
turnover number,
AREA_ID number references area(id));
please look into this and help me to fish out the problem
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