001/* 002 * Copyright 2002-2018 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.SQLException; 020import java.sql.Statement; 021 022import org.springframework.dao.DataAccessException; 023import org.springframework.lang.Nullable; 024 025/** 026 * Generic callback interface for code that operates on a JDBC Statement. 027 * Allows to execute any number of operations on a single Statement, 028 * for example a single {@code executeUpdate} call or repeated 029 * {@code executeUpdate} calls with varying SQL. 030 * 031 * <p>Used internally by JdbcTemplate, but also useful for application code. 032 * 033 * @author Juergen Hoeller 034 * @since 16.03.2004 035 * @param <T> the result type 036 * @see JdbcTemplate#execute(StatementCallback) 037 */ 038@FunctionalInterface 039public interface StatementCallback<T> { 040 041 /** 042 * Gets called by {@code JdbcTemplate.execute} with an active JDBC 043 * Statement. Does not need to care about closing the Statement or the 044 * Connection, or about handling transactions: this will all be handled 045 * by Spring's JdbcTemplate. 046 * <p><b>NOTE:</b> Any ResultSets opened should be closed in finally blocks 047 * within the callback implementation. Spring will close the Statement 048 * object after the callback returned, but this does not necessarily imply 049 * that the ResultSet resources will be closed: the Statement objects might 050 * get pooled by the connection pool, with {@code close} calls only 051 * returning the object to the pool but not physically closing the resources. 052 * <p>If called without a thread-bound JDBC transaction (initiated by 053 * DataSourceTransactionManager), the code will simply get executed on the 054 * JDBC connection with its transactional semantics. If JdbcTemplate is 055 * configured to use a JTA-aware DataSource, the JDBC connection and thus 056 * the callback code will be transactional if a JTA transaction is active. 057 * <p>Allows for returning a result object created within the callback, i.e. 058 * a domain object or a collection of domain objects. Note that there's 059 * special support for single step actions: see JdbcTemplate.queryForObject etc. 060 * A thrown RuntimeException is treated as application exception, it gets 061 * propagated to the caller of the template. 062 * @param stmt active JDBC Statement 063 * @return a result object, or {@code null} if none 064 * @throws SQLException if thrown by a JDBC method, to be auto-converted 065 * to a DataAccessException by an SQLExceptionTranslator 066 * @throws DataAccessException in case of custom exceptions 067 * @see JdbcTemplate#queryForObject(String, Class) 068 * @see JdbcTemplate#queryForRowSet(String) 069 */ 070 @Nullable 071 T doInStatement(Statement stmt) throws SQLException, DataAccessException; 072 073}