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Java > Open Source Codes > org > springframework > jdbc > object > UpdatableSqlQuery


1 /*
2  * Copyright 2002-2005 the original author or authors.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.springframework.jdbc.object;
18
19 import java.sql.ResultSet JavaDoc;
20 import java.sql.SQLException JavaDoc;
21 import java.util.Map JavaDoc;
22
23 import javax.sql.DataSource JavaDoc;
24
25 import org.springframework.jdbc.core.RowMapper;
26
27 /**
28  * Reusable RDBMS query in which concrete subclasses must implement
29  * the abstract updateRow(ResultSet, int, context) method to update each
30  * row of the JDBC ResultSet and optionally map contents into an object.
31  *
32  * <p>Subclasses can be constructed providing SQL, parameter types
33  * and a DataSource. SQL will often vary between subclasses.
34  *
35  * @author Thomas Risberg
36  * @see org.springframework.jdbc.object.SqlQuery
37  */
38 public abstract class UpdatableSqlQuery extends SqlQuery {
39
40     /**
41      * Constructor to allow use as a JavaBean
42      */
43     public UpdatableSqlQuery() {
44         setUpdatableResults(true);
45     }
46
47     /**
48      * Convenient constructor with DataSource and SQL string.
49      * @param ds DataSource to use to get connections
50      * @param sql SQL to run
51      */
52     public UpdatableSqlQuery(DataSource JavaDoc ds, String JavaDoc sql) {
53         super(ds, sql);
54         setUpdatableResults(true);
55     }
56
57     /**
58      * Implementation of the superclass template method. This invokes the subclass's
59      * implementation of the <code>updateRow()</code> method.
60      */
61     protected RowMapper newRowMapper(Object JavaDoc[] parameters, Map JavaDoc context) {
62         return new RowMapperImpl(context);
63     }
64
65     /**
66      * Subclasses must implement this method to update each row of the
67      * ResultSet and optionally create object of the result type.
68      * @param rs ResultSet we're working through
69      * @param rowNum row number (from 0) we're up to
70      * @param context passed to the execute() method.
71      * It can be <code>null</code> if no contextual information is need. If you
72      * need to pass in data for each row, you can pass in a HashMap with
73      * the primary key of the row being the key for the HashMap. That way
74      * it is easy to locate the updates for each row
75      * @return an object of the result type
76      * @throws SQLException if there's an error updateing data.
77      * Subclasses can simply not catch SQLExceptions, relying on the
78      * framework to clean up.
79      */
80     protected abstract Object JavaDoc updateRow(ResultSet JavaDoc rs, int rowNum, Map JavaDoc context) throws SQLException JavaDoc;
81
82
83     /**
84      * Implementation of RowMapper that calls the enclosing
85      * class's <code>updateRow()</code> method for each row.
86      */
87     protected class RowMapperImpl implements RowMapper {
88
89         private final Map JavaDoc context;
90
91         public RowMapperImpl(Map JavaDoc context) {
92             this.context = context;
93         }
94
95         public Object JavaDoc mapRow(ResultSet JavaDoc rs, int rowNum) throws SQLException JavaDoc {
96             Object JavaDoc result = updateRow(rs, rowNum, this.context);
97             rs.updateRow();
98             return result;
99         }
100     }
101
102 }
103
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