Java tutorial
/* * Copyright 2002-2018 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.jdbc.core; import java.sql.Connection; import java.sql.SQLException; import org.springframework.dao.DataAccessException; import org.springframework.lang.Nullable; /** * Generic callback interface for code that operates on a JDBC Connection. * Allows to execute any number of operations on a single Connection, * using any type and number of Statements. * * <p>This is particularly useful for delegating to existing data access code * that expects a Connection to work on and throws SQLException. For newly * written code, it is strongly recommended to use JdbcTemplate's more specific * operations, for example a {@code query} or {@code update} variant. * * @author Juergen Hoeller * @since 1.1.3 * @param <T> the result type * @see JdbcTemplate#execute(ConnectionCallback) * @see JdbcTemplate#query * @see JdbcTemplate#update */ @FunctionalInterface public interface ConnectionCallback<T> { /** * Gets called by {@code JdbcTemplate.execute} with an active JDBC * Connection. Does not need to care about activating or closing the * Connection, or handling transactions. * <p>If called without a thread-bound JDBC transaction (initiated by * DataSourceTransactionManager), the code will simply get executed on the * JDBC connection with its transactional semantics. If JdbcTemplate is * configured to use a JTA-aware DataSource, the JDBC Connection and thus * the callback code will be transactional if a JTA transaction is active. * <p>Allows for returning a result object created within the callback, i.e. * a domain object or a collection of domain objects. Note that there's special * support for single step actions: see {@code JdbcTemplate.queryForObject} * etc. A thrown RuntimeException is treated as application exception: * it gets propagated to the caller of the template. * @param con active JDBC Connection * @return a result object, or {@code null} if none * @throws SQLException if thrown by a JDBC method, to be auto-converted * to a DataAccessException by a SQLExceptionTranslator * @throws DataAccessException in case of custom exceptions * @see JdbcTemplate#queryForObject(String, Class) * @see JdbcTemplate#queryForRowSet(String) */ @Nullable T doInConnection(Connection con) throws SQLException, DataAccessException; }