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.ResultSet;
020import java.sql.ResultSetMetaData;
021import java.sql.SQLException;
022import java.util.Map;
023
024import org.springframework.jdbc.support.JdbcUtils;
025import org.springframework.util.LinkedCaseInsensitiveMap;
026
027/**
028 * {@link RowMapper} implementation that creates a {@code java.util.Map}
029 * for each row, representing all columns as key-value pairs: one
030 * entry for each column, with the column name as key.
031 *
032 * <p>The Map implementation to use and the key to use for each column
033 * in the column Map can be customized through overriding
034 * {@link #createColumnMap} and {@link #getColumnKey}, respectively.
035 *
036 * <p><b>Note:</b> By default, ColumnMapRowMapper will try to build a linked Map
037 * with case-insensitive keys, to preserve column order as well as allow any
038 * casing to be used for column names. This requires Commons Collections on the
039 * classpath (which will be autodetected). Else, the fallback is a standard linked
040 * HashMap, which will still preserve column order but requires the application
041 * to specify the column names in the same casing as exposed by the driver.
042 *
043 * @author Juergen Hoeller
044 * @since 1.2
045 * @see JdbcTemplate#queryForList(String)
046 * @see JdbcTemplate#queryForMap(String)
047 */
048public class ColumnMapRowMapper implements RowMapper<Map<String, Object>> {
049
050        @Override
051        public Map<String, Object> mapRow(ResultSet rs, int rowNum) throws SQLException {
052                ResultSetMetaData rsmd = rs.getMetaData();
053                int columnCount = rsmd.getColumnCount();
054                Map<String, Object> mapOfColumnValues = createColumnMap(columnCount);
055                for (int i = 1; i <= columnCount; i++) {
056                        String column = JdbcUtils.lookupColumnName(rsmd, i);
057                        mapOfColumnValues.put(getColumnKey(column), getColumnValue(rs, i));
058                }
059                return mapOfColumnValues;
060        }
061
062        /**
063         * Create a Map instance to be used as column map.
064         * <p>By default, a linked case-insensitive Map will be created.
065         * @param columnCount the column count, to be used as initial
066         * capacity for the Map
067         * @return the new Map instance
068         * @see org.springframework.util.LinkedCaseInsensitiveMap
069         */
070        protected Map<String, Object> createColumnMap(int columnCount) {
071                return new LinkedCaseInsensitiveMap<Object>(columnCount);
072        }
073
074        /**
075         * Determine the key to use for the given column in the column Map.
076         * @param columnName the column name as returned by the ResultSet
077         * @return the column key to use
078         * @see java.sql.ResultSetMetaData#getColumnName
079         */
080        protected String getColumnKey(String columnName) {
081                return columnName;
082        }
083
084        /**
085         * Retrieve a JDBC object value for the specified column.
086         * <p>The default implementation uses the {@code getObject} method.
087         * Additionally, this implementation includes a "hack" to get around Oracle
088         * returning a non standard object for their TIMESTAMP datatype.
089         * @param rs is the ResultSet holding the data
090         * @param index is the column index
091         * @return the Object returned
092         * @see org.springframework.jdbc.support.JdbcUtils#getResultSetValue
093         */
094        protected Object getColumnValue(ResultSet rs, int index) throws SQLException {
095                return JdbcUtils.getResultSetValue(rs, index);
096        }
097
098}