import javax.ejb.SessionContext;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.transaction.*;

public class Transaction {
  UserTransaction txn;

  public void setSessionContext( SessionContext ctx ) {
    ctx.getUserTransaction();
  }
  public Transaction() {
    InitialContext ic = null;
    try {
      ic = new InitialContext();
      txn = (UserTransaction)ic.lookup(
          "java:comp/UserTransaction");
    } catch (NamingException e) {
    }
  }
  public void begin()
      throws SystemException, NotSupportedException {
    txn.begin();
  }

  public void commit()
      throws SystemException, HeuristicRollbackException,
      RollbackException, HeuristicMixedException {
    txn.commit();
  }

  public void rollback() throws SystemException {
    txn.rollback();
  }
}