001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * -------------------
028 * JDBCPieDataset.java
029 * -------------------
030 * (C) Copyright 2002-2008, by Bryan Scott and Contributors.
031 *
032 * Original Author: Bryan Scott; Andy
033 * Contributor(s): David Gilbert (for Object Refinery Limited);
034 * Thomas Morgner;
035 *
036 * Changes
037 * -------
038 * 26-Apr-2002 : Creation based on JdbcXYDataSet, but extending
039 * DefaultPieDataset (BS);
040 * 24-Jun-2002 : Removed unnecessary import and local variable (DG);
041 * 13-Aug-2002 : Updated Javadoc comments and imports, removed default
042 * constructor (DG);
043 * 18-Sep-2002 : Updated to support BIGINT (BS);
044 * 21-Jan-2003 : Renamed JdbcPieDataset --> JDBCPieDataset (DG);
045 * 03-Feb-2003 : Added Types.DECIMAL (see bug report 677814) (DG);
046 * 05-Jun-2003 : Updated to support TIME, optimised executeQuery method (BS);
047 * 30-Jul-2003 : Added empty contructor and executeQuery(connection,string)
048 * method (BS);
049 * 02-Dec-2003 : Throwing exceptions allows to handle errors, removed default
050 * constructor, as without a connection, a query can never be
051 * executed (TM);
052 * 04-Dec-2003 : Added missing Javadocs (DG);
053 * ------------- JFREECHART 1.0.x ---------------------------------------------
054 * 02-Feb-2007 : Removed author tags all over JFreeChart sources (DG);
055 *
056 */
057
058 package org.jfree.data.jdbc;
059
060 import java.sql.Connection;
061 import java.sql.DriverManager;
062 import java.sql.ResultSet;
063 import java.sql.ResultSetMetaData;
064 import java.sql.SQLException;
065 import java.sql.Statement;
066 import java.sql.Timestamp;
067 import java.sql.Types;
068
069 import org.jfree.data.general.DefaultPieDataset;
070 import org.jfree.data.general.PieDataset;
071
072 /**
073 * A {@link PieDataset} that reads data from a database via JDBC.
074 * <P>
075 * A query should be supplied that returns data in two columns, the first
076 * containing VARCHAR data, and the second containing numerical data. The
077 * data is cached in-memory and can be refreshed at any time.
078 */
079 public class JDBCPieDataset extends DefaultPieDataset {
080
081 /** For serialization. */
082 static final long serialVersionUID = -8753216855496746108L;
083
084 /** The database connection. */
085 private transient Connection connection;
086
087 /**
088 * Creates a new JDBCPieDataset and establishes a new database connection.
089 *
090 * @param url the URL of the database connection.
091 * @param driverName the database driver class name.
092 * @param user the database user.
093 * @param password the database users password.
094 *
095 * @throws ClassNotFoundException if the driver cannot be found.
096 * @throws SQLException if there is a problem obtaining a database
097 * connection.
098 */
099 public JDBCPieDataset(String url,
100 String driverName,
101 String user,
102 String password)
103 throws SQLException, ClassNotFoundException {
104
105 Class.forName(driverName);
106 this.connection = DriverManager.getConnection(url, user, password);
107 }
108
109 /**
110 * Creates a new JDBCPieDataset using a pre-existing database connection.
111 * <P>
112 * The dataset is initially empty, since no query has been supplied yet.
113 *
114 * @param con the database connection.
115 */
116 public JDBCPieDataset(Connection con) {
117 if (con == null) {
118 throw new NullPointerException("A connection must be supplied.");
119 }
120 this.connection = con;
121 }
122
123
124 /**
125 * Creates a new JDBCPieDataset using a pre-existing database connection.
126 * <P>
127 * The dataset is initialised with the supplied query.
128 *
129 * @param con the database connection.
130 * @param query the database connection.
131 *
132 * @throws SQLException if there is a problem executing the query.
133 */
134 public JDBCPieDataset(Connection con, String query) throws SQLException {
135 this(con);
136 executeQuery(query);
137 }
138
139 /**
140 * ExecuteQuery will attempt execute the query passed to it against the
141 * existing database connection. If no connection exists then no action
142 * is taken.
143 * The results from the query are extracted and cached locally, thus
144 * applying an upper limit on how many rows can be retrieved successfully.
145 *
146 * @param query the query to be executed.
147 *
148 * @throws SQLException if there is a problem executing the query.
149 */
150 public void executeQuery(String query) throws SQLException {
151 executeQuery(this.connection, query);
152 }
153
154 /**
155 * ExecuteQuery will attempt execute the query passed to it against the
156 * existing database connection. If no connection exists then no action
157 * is taken.
158 * The results from the query are extracted and cached locally, thus
159 * applying an upper limit on how many rows can be retrieved successfully.
160 *
161 * @param query the query to be executed
162 * @param con the connection the query is to be executed against
163 *
164 * @throws SQLException if there is a problem executing the query.
165 */
166 public void executeQuery(Connection con, String query) throws SQLException {
167
168 Statement statement = null;
169 ResultSet resultSet = null;
170
171 try {
172 statement = con.createStatement();
173 resultSet = statement.executeQuery(query);
174 ResultSetMetaData metaData = resultSet.getMetaData();
175
176 int columnCount = metaData.getColumnCount();
177 if (columnCount != 2) {
178 throw new SQLException(
179 "Invalid sql generated. PieDataSet requires 2 columns only"
180 );
181 }
182
183 int columnType = metaData.getColumnType(2);
184 double value = Double.NaN;
185 while (resultSet.next()) {
186 Comparable key = resultSet.getString(1);
187 switch (columnType) {
188 case Types.NUMERIC:
189 case Types.REAL:
190 case Types.INTEGER:
191 case Types.DOUBLE:
192 case Types.FLOAT:
193 case Types.DECIMAL:
194 case Types.BIGINT:
195 value = resultSet.getDouble(2);
196 setValue(key, value);
197 break;
198
199 case Types.DATE:
200 case Types.TIME:
201 case Types.TIMESTAMP:
202 Timestamp date = resultSet.getTimestamp(2);
203 value = date.getTime();
204 setValue(key, value);
205 break;
206
207 default:
208 System.err.println(
209 "JDBCPieDataset - unknown data type"
210 );
211 break;
212 }
213 }
214
215 fireDatasetChanged();
216
217 }
218 finally {
219 if (resultSet != null) {
220 try {
221 resultSet.close();
222 }
223 catch (Exception e) {
224 System.err.println("JDBCPieDataset: swallowing exception.");
225 }
226 }
227 if (statement != null) {
228 try {
229 statement.close();
230 }
231 catch (Exception e) {
232 System.err.println("JDBCPieDataset: swallowing exception.");
233 }
234 }
235 }
236 }
237
238
239 /**
240 * Close the database connection
241 */
242 public void close() {
243 try {
244 this.connection.close();
245 }
246 catch (Exception e) {
247 System.err.println("JdbcXYDataset: swallowing exception.");
248 }
249 }
250 }