package ejava.examples.ejbsessionbank.jpa;
   
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.HashMap;
   import java.util.List;
   import java.util.Map;
   
   import javax.persistence.EntityManager;
  import javax.persistence.Query;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import ejava.examples.ejbsessionbank.bo.Account;
  import ejava.examples.ejbsessionbank.bo.Owner;
  import ejava.examples.ejbsessionbank.dao.DAOException;
  import ejava.examples.ejbsessionbank.dao.OwnerDAO;
  
  public class JPAOwnerDAO implements OwnerDAO {
      static final Log log = LogFactory.getLog(JPAOwnerDAO.class);
      
      static final String COUNT_ACCOUNT_REFERENCES_QUERY = 
          "countAccountReferences";
      
      private EntityManager em;
  
      public void setEntityManager(EntityManager em) {
          this.em = em;
      }
  
      public Owner createOwner(Owner owner) throws DAOException {
          em.persist(owner);
          return owner;
      }
  
      @SuppressWarnings("unchecked")
      public List<Owner> findOwners(String queryName, Map<String, Object> params,
              int index, int count) throws DAOException {
          Query query = em.createNamedQuery(queryName);
          if (params != null && params.size() > 0) {
              for (String key : params.keySet()) {
                  Object value = params.get(key);
                  query.setParameter(key, value);
              }
          }
          return query.setFirstResult(index)
                       .setMaxResults(count)
                       .getResultList();
      }
  
      public Owner getOwnerById(long id) throws DAOException {
          return em.find(Owner.class, id);
      }
  
      public Owner removeOwner(Owner owner) throws DAOException {
          if (!em.contains(owner)) {
              owner = em.find(Owner.class, owner.getId());
          }
          if (owner != null) {
              Collection<Account> accounts = new ArrayList<Account>();
              accounts.addAll(owner.getAccounts());
              for (Account a: accounts) {
                  owner.getAccounts().remove(a);
      
                  //don't delete account if referenced by other owners
                  if (((Long)em.createNamedQuery(COUNT_ACCOUNT_REFERENCES_QUERY)
                        .setParameter("account", a)
                        .getSingleResult()) == 0) {
                      em.remove(a);
                  }
              }
              em.remove(owner);
          }
          return owner;
      }
  
  	public List<Owner> getAccountOwners(Account account) throws DAOException {
          Map<String, Object> params = new HashMap<String, Object>();
          params.put("account", account);
          List<Owner> owners = 
          	findOwners("getAccountOwner", params, 0, 100);
          return owners;
  	}
  }