Java Tutorial/EJB3/Transaction

Bean Managed Transaction

File: EmployeeBean.java

import javax.annotation.Resource;
import javax.ejb.EJBException;
import javax.ejb.Stateless;
import javax.ejb.TransactionManagement;
import javax.ejb.TransactionManagementType;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.transaction.UserTransaction;
@Stateless
@TransactionManagement(TransactionManagementType.BEAN)
public class EmployeeBean implements EmployeeServiceLocal, EmployeeServiceRemote {
  @PersistenceContext(unitName = "EmployeeService")
  private EntityManager manager;
  @Resource UserTransaction tx;
  public void doAction() {
    try {
      try {
          tx.begin();
          // do the work...
          System.out.println("Processing...");
      } finally {
          tx.rumit();
      }
  } catch (Exception e) {
      // handle all the tx.begin()/commit() exceptions
      throw new EJBException(e);
  }
  }
}

Container Managed Transaction Attribute Type: REQUIRED

File: EmployeeBean.java

import javax.ejb.Stateless;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
@Stateless
public class EmployeeBean implements EmployeeServiceLocal, EmployeeServiceRemote {
  @PersistenceContext(unitName = "EmployeeService")
  private EntityManager manager;

  @TransactionAttribute(TransactionAttributeType.REQUIRED)
  public void doAction() {
    Customer cust = new Customer();
    cust.setFirstName("Joe");
    manager.persist(cust);
    
    System.out.println("Saved");
    
    cust = manager.find(Customer.class,cust.getSsn());
    
    System.out.println(cust.getFirstName());
    cust.setFirstName("new Name");
    
    manager.merge(cust);
    cust = manager.find(Customer.class,cust.getSsn());
    
    System.out.println(cust.getFirstName());
  }
}

Transaction Attribute Type: REQUIRES_NEW

File: Customer.java

import javax.persistence.Entity;
import javax.persistence.EntityListeners;
import javax.persistence.Id;
import javax.persistence.PostRemove;
@Entity
public class Customer implements java.io.Serializable {
  private String firstName;
  private String lastName;
  @Id
  private long ssn;
  public String getFirstName() {
    return firstName;
  }
  public void setFirstName(String firstName) {
    this.firstName = firstName;
  }

  public String getLastName() {
    return lastName;
  }
  public void setLastName(String lastName) {
    this.lastName = lastName;
  }

  public long getSsn() {
    return ssn;
  }
  public void setSsn(long ssn) {
    this.ssn = ssn;
  }
}