001/* 002 * Copyright 2002-2012 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.jdbc.core; 018 019import java.sql.ResultSet; 020import java.sql.SQLException; 021 022import org.springframework.dao.DataAccessException; 023 024/** 025 * Callback interface used by {@link JdbcTemplate}'s query methods. 026 * Implementations of this interface perform the actual work of extracting 027 * results from a {@link java.sql.ResultSet}, but don't need to worry 028 * about exception handling. {@link java.sql.SQLException SQLExceptions} 029 * will be caught and handled by the calling JdbcTemplate. 030 * 031 * <p>This interface is mainly used within the JDBC framework itself. 032 * A {@link RowMapper} is usually a simpler choice for ResultSet processing, 033 * mapping one result object per row instead of one result object for 034 * the entire ResultSet. 035 * 036 * <p>Note: In contrast to a {@link RowCallbackHandler}, a ResultSetExtractor 037 * object is typically stateless and thus reusable, as long as it doesn't 038 * access stateful resources (such as output streams when streaming LOB 039 * contents) or keep result state within the object. 040 * 041 * @author Rod Johnson 042 * @author Juergen Hoeller 043 * @since April 24, 2003 044 * @see JdbcTemplate 045 * @see RowCallbackHandler 046 * @see RowMapper 047 * @see org.springframework.jdbc.core.support.AbstractLobStreamingResultSetExtractor 048 */ 049public interface ResultSetExtractor<T> { 050 051 /** 052 * Implementations must implement this method to process the entire ResultSet. 053 * @param rs ResultSet to extract data from. Implementations should 054 * not close this: it will be closed by the calling JdbcTemplate. 055 * @return an arbitrary result object, or {@code null} if none 056 * (the extractor will typically be stateful in the latter case). 057 * @throws SQLException if a SQLException is encountered getting column 058 * values or navigating (that is, there's no need to catch SQLException) 059 * @throws DataAccessException in case of custom exceptions 060 */ 061 T extractData(ResultSet rs) throws SQLException, DataAccessException; 062 063}