1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.dbutils;
18
19 import java.sql.ResultSet;
20 import java.sql.SQLException;
21
22 /**
23 * Defines how to process columns when constructing a bean from a {@link ResultSet}. Instances do the work of retrieving data from a {@code ResultSet}.
24 *
25 * @param <T> The return type.
26 */
27 public interface ColumnHandler<T> {
28
29 /**
30 * Retrieves the current row's column value from a {@link ResultSet} and stores it into an instance of {@code propType}. This method is only called if
31 * {@link #match(Class)} returns true.
32 *
33 * @param resultSet The source result set. This must be on the correct row.
34 * @param columnIndex The position of the column to retrieve, a 1-based index.
35 * @return The converted value or the original value if something doesn't work out.
36 * @throws SQLException if the columnIndex is not valid; if a database access error occurs or this method is called on a closed result set
37 */
38 T apply(ResultSet resultSet, int columnIndex) throws SQLException;
39
40 /**
41 * Tests whether to handle a column targeted for a value type matching {@code propType}.
42 *
43 * @param propType The type of the target parameter.
44 * @return true is this property handler handles this {@code propType}; false otherwise.
45 */
46 boolean match(Class<?> propType);
47 }