/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2017, Open Source Geospatial Foundation (OSGeo)
 *    
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.geotools.jdbc;

import java.sql.ResultSet;
import java.sql.Statement;

/**
 * Callback for {@link JDBCFeatureReader}.
 */
public interface JDBCReaderCallback {

  /**
   * Null callback. 
   */
  JDBCReaderCallback NULL = new JDBCReaderCallback() {};

  /**
   * Called when the reader is created.
   * 
   * @param reader The feature reader.
   */
  default void init(JDBCFeatureReader reader) {}

  /**
   * Called directly before the reader makes it's initial query to the database.
   * 
   * @param st The query statement being executed. 
   */
  default void beforeQuery(Statement st) {}

  /**
   * Called directly after the reader makes it's initial query to the database.
   * 
   * @param st The query statement that was executed.
   */
  default void afterQuery(Statement st) {}

  /**
   * Called when an error occurs making the initial query to the database.
   */
  default void queryError(Exception e) {}

  /**
   * Called before the reader makes a call to {@link java.sql.ResultSet#next()}.
   * 
   * @param rs The result set.
   */
  default void beforeNext(ResultSet rs) {}

  /**
   * Called after the reader makes a call to {@link java.sql.ResultSet#next()}.
   *
   * @param rs The result set.
   * @param hasMore Whether or not any more rows exist in the {@link java.sql.ResultSet}
   */
  default void afterNext(ResultSet rs, boolean hasMore) {}

  /**
   * Called when an error occurs fetching the next row in the result set.
   * 
   * @param e The error thrown.
   */
  default void rowError(Exception e) {}

  /**
   * Called after the last row from the reader {@link java.sql.ResultSet} is read.
   * 
   * @param reader The feature reader.
   */
  default void finish(JDBCFeatureReader reader) {}
}