package de.uhilger.baselink;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author Ulrich Hilger
 */
public class Updater extends DBActor {
  private static final Logger logger = Logger.getLogger(Updater.class.getName());
  
  public Updater(PersistenceManager pm) {
    this.pm = pm;
  }

  /**
   * update an object in the database
   *
   * <p>Use this method for single updates. In cases where
   * several subsequent updates for objects of the same class
   * are required the use of method <code>update(Object, Record)</code>
   * is recommended instead to minimise instantiation
   * overhead.</p>
   *
   * @param o  object to update
   * @return  the object that was updated
   */
  public Object update(Object o) {
    return update(o, new GenericRecord(o.getClass()));
  }

  /**
   * update an object in the database
   *
   * <p>Use this method for single updates. In cases where
   * several subsequent updates for objects of the same class
   * are required the use of method <code>update(Connection, Object, Record)</code>
   * is recommended instead to minimise instantiation
   * overhead.</p>
   *
   * @param c the connection to use, expected to be open and established
   * @param o object to update
   * @return  the object that was updated
   */
  public Object update(Connection c, Object o) {
    return update(c, o, new GenericRecord(o.getClass()));
  }

  /**
   * update an object in the database
   * @param o object to update
   * @param record reference to object to use to map between object and database
   * @return  the object that was updated
   */
  public Object update(Object o, Record record) {
    Connection c = null;
    try {
      c = pm.getConnection();
      o = update(c, o, record);
      c.close();
      c = null;
    } catch (SQLException ex) {
      logger.log(Level.SEVERE, ex.getLocalizedMessage(), ex);
    } finally {
      pm.closeConnectionFinally(c);
    }
    return o;
  }

  /**
   * update an object in the database
   * @param c the connection to use, expected to be open and established
   * @param o object to update
   * @param record reference to object to use to map between object and database
   * @return  the object that was updated
   */
  public Object update(Connection c, Object o, Record record) {
    Object updatedObject = null;
    PreparedStatement ps = null;
    try {
      ps = record.getUpdateStatment(c, o);
      ps.executeUpdate();
      ps.close();
      ps = null;
      updatedObject = o;
    } catch (Exception ex) {
      logger.log(Level.SEVERE, ex.getLocalizedMessage(), ex);
    } finally {
      pm.closeStatementFinally(ps);
    }
    return updatedObject;
  }
    
}