[jboss-user] [JBoss Seam] - Right approach using EntityManager and MDB
Hi
I have not much experience with MDBs.
I need to use EntityManager in combination with a MDB. As I have seen here in forum an
other user have used this in the same way as follow:
MDB
package de.oats.business.mdb;
|
| import javax.annotation.Resource;
| import javax.ejb.ActivationConfigProperty;
| import javax.ejb.MessageDriven;
| import javax.ejb.MessageDrivenContext;
| import javax.jms.Message;
| import javax.jms.MessageListener;
| import javax.jms.ObjectMessage;
|
| import org.jboss.annotation.ejb.PoolClass;
| import org.jboss.seam.annotations.In;
|
|
| @MessageDriven(name="QueryMessageBean", activationConfig = {
| @ActivationConfigProperty(propertyName="destinationType",
propertyValue="javax.jms.Queue"),
| @ActivationConfigProperty(propertyName="destination",
propertyValue="queue/oatsMessageQueue")
|
| })
| @PoolClass(value=org.jboss.ejb3.StrictMaxPool.class, maxSize=1)
| public class QueryMessageBean implements MessageListener {
|
| @Resource
| private MessageDrivenContext context;
| @In(create=true)
| private UserQuery userquery;
|
| public void onMessage(Message message) {
| QueryTest name = null;
|
| try {
| if (message instanceof ObjectMessage) {
| ObjectMessage objMessage = (ObjectMessage) message;
| Object obj = objMessage.getObject();
| if (obj instanceof QueryTest) {
| name = (QueryTest) obj;
| userquery.setSqlQuery(name.getSqlQuery());
| userquery.query();
| } else {
| System.err.println("Expecting ProcessDTO in Message");
| }
| } else {
| System.err.println("Expecting Object Message");
| }
| } catch (Throwable t) {
| t.printStackTrace();
| context.setRollbackOnly();
| }
| }
| }
|
|
SLSB
package de.oats.business.mdb;
|
| import java.io.Serializable;
| import java.sql.Connection;
| import java.sql.ResultSet;
| import java.sql.Statement;
| import java.util.Date;
|
| import javax.ejb.Stateless;
| import javax.persistence.EntityManager;
| import javax.persistence.PersistenceContext;
|
| import org.jboss.seam.annotations.In;
| import org.jboss.seam.annotations.Name;
|
| import de.oats.model.QueryResult;
|
| @Stateless
| @Name("userQuery")
| public class UserQueryBean implements UserQuery{
|
| private String sqlQuery;
|
| private static Connection con = null;
| @PersistenceContext
| private EntityManager entityManager;
|
| public UserQueryBean() {
| super();
| }
|
| public String query(){
| ResultSet rs;
| Statement stmt;
| try {
| con = MysqlCon.getConnection();
| stmt = con.createStatement();
|
| rs = stmt.executeQuery(sqlQuery);
| QueryResult qrslt = null;
| while(rs.next()){
| qrslt = new QueryResult();
| qrslt.setAnzahl(rs.getLong("anzahl"));
| qrslt.setY20gpnum(rs.getString("y20gpnum"));
| qrslt.setLat(rs.getDouble("lat"));
| qrslt.setLon(rs.getDouble("lon"));
|
| entityManager.persist(qrslt);
| }
| entityManager.flush();
| } catch (Exception e) {
| // TODO Auto-generated catch block
| e.printStackTrace();
| }
| return "5 seconds for " +kindOfQuery;
| }
| public void setSqlQuery(String sqlQuery) {
| this.sqlQuery = sqlQuery;
| }
|
| }
|
But userquery is always null in spite of @In(create=true)
An other try was to put EntityManager in the ObjectMessage(UserTest) - here is null value
on entityManager.
Use Seam 2.0 (seam generatet project) and jboss-4.2.1.GA
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