1. /*

  2.  * Copyright 2002-2004 the original author or authors.

  3.  *

  4.  * Licensed under the Apache License, Version 2.0 (the "License");

  5.  * you may not use this file except in compliance with the License.

  6.  * You may obtain a copy of the License at

  7.  *

  8.  *      http://www.apache.org/licenses/LICENSE-2.0

  9.  *

  10.  * Unless required by applicable law or agreed to in writing, software

  11.  * distributed under the License is distributed on an "AS IS" BASIS,

  12.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  13.  * See the License for the specific language governing permissions and

  14.  * limitations under the License.

  15.  */

  16. 

  17. package org.springframework.jdbc.core;

  18. 

  19. import java.sql.ResultSet;

  20. import java.sql.SQLException;

  21. 

  22. /**

  23.  * Callback interface used by JdbcTemplate's query methods.

  24.  * Implementations of this interface perform the actual work of extracting

  25.  * results, but don't need to worry about exception handling. SQLExceptions

  26.  * will be caught and handled correctly by the JdbcTemplate class.

  27.  *

  28.  * <p>In contrast to a ResultSetExtractor, a RowCallbackHandler object is

  29.  * typically stateful: It keeps the result state within the object, to be

  30.  * available for later inspection. See RowCountCallbackHandler's javadoc

  31.  * for a usage example with JdbcTemplate.

  32.  *

  33.  * <p>The ResultReader subinterface allows to make a results list available

  34.  * in a uniform manner. JdbcTemplate's query methods will return the results

  35.  * list in that case, else returning null (-> result state is solely

  36.  * available from RowCallbackHandler object).

  37.  *

  38.  * <p>A convenient out-of-the-box implementation of RowCallbackHandler is the

  39.  * RowMapperResultReader adapter which delegates row mapping to a RowMapper.

  40.  * Note that a RowMapper object is typically stateless and thus reusable;

  41.  * just the RowMapperResultReader adapter is stateful.

  42.  *

  43.  * @author Rod Johnson

  44.  * @see ResultSetExtractor

  45.  * @see RowCountCallbackHandler

  46.  * @see ResultReader

  47.  * @see RowMapperResultReader

  48.  * @see RowMapper

  49.  */

  50. public interface RowCallbackHandler {

  51. 

  52. 	/**

  53. 	 * Implementations must implement this method to process each row of data

  54. 	 * in the ResultSet. This method should not call next() on the ResultSet,

  55. 	 * but extract the current values. Exactly what the implementation chooses

  56. 	 * to do is up to it; a trivial implementation might simply count rows,

  57. 	 * while another implementation might build an XML document.

  58. 	 * @param rs the ResultSet to process

  59. 	 * @throws SQLException if a SQLException is encountered getting

  60. 	 * column values (that is, there's no need to catch SQLException)

  61. 	 */

  62. 	void processRow(ResultSet rs) throws SQLException;

  63. 

  64. }