001/*
002 * Copyright 2002-2008 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.object;
018
019import java.sql.ResultSet;
020import java.sql.SQLException;
021import java.util.Map;
022import javax.sql.DataSource;
023
024/**
025 * Reusable query in which concrete subclasses must implement the abstract
026 * mapRow(ResultSet, int) method to convert each row of the JDBC ResultSet
027 * into an object.
028 *
029 * <p>Simplifies MappingSqlQueryWithParameters API by dropping parameters and
030 * context. Most subclasses won't care about parameters. If you don't use
031 * contextual information, subclass this instead of MappingSqlQueryWithParameters.
032 *
033 * @author Rod Johnson
034 * @author Thomas Risberg
035 * @author Jean-Pierre Pawlak
036 * @see MappingSqlQueryWithParameters
037 */
038public abstract class MappingSqlQuery<T> extends MappingSqlQueryWithParameters<T> {
039
040        /**
041         * Constructor that allows use as a JavaBean.
042         */
043        public MappingSqlQuery() {
044        }
045
046        /**
047         * Convenient constructor with DataSource and SQL string.
048         * @param ds DataSource to use to obtain connections
049         * @param sql SQL to run
050         */
051        public MappingSqlQuery(DataSource ds, String sql) {
052                super(ds, sql);
053        }
054
055
056        /**
057         * This method is implemented to invoke the simpler mapRow
058         * template method, ignoring parameters.
059         * @see #mapRow(ResultSet, int)
060         */
061        @Override
062        protected final T mapRow(ResultSet rs, int rowNum, Object[] parameters, Map<?, ?> context)
063                        throws SQLException {
064
065                return mapRow(rs, rowNum);
066        }
067
068        /**
069         * Subclasses must implement this method to convert each row of the
070         * ResultSet into an object of the result type.
071         * <p>Subclasses of this class, as opposed to direct subclasses of
072         * MappingSqlQueryWithParameters, don't need to concern themselves
073         * with the parameters to the execute method of the query object.
074         * @param rs ResultSet we're working through
075         * @param rowNum row number (from 0) we're up to
076         * @return an object of the result type
077         * @throws SQLException if there's an error extracting data.
078         * Subclasses can simply not catch SQLExceptions, relying on the
079         * framework to clean up.
080         */
081        protected abstract T mapRow(ResultSet rs, int rowNum) throws SQLException;
082
083}