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1: /* =========================================================== 2: * JFreeChart : a free chart library for the Java(tm) platform 3: * =========================================================== 4: * 5: * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors. 6: * 7: * Project Info: http://www.jfree.org/jfreechart/index.html 8: * 9: * This library is free software; you can redistribute it and/or modify it 10: * under the terms of the GNU Lesser General Public License as published by 11: * the Free Software Foundation; either version 2.1 of the License, or 12: * (at your option) any later version. 13: * 14: * This library is distributed in the hope that it will be useful, but 15: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 16: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 17: * License for more details. 18: * 19: * You should have received a copy of the GNU Lesser General Public 20: * License along with this library; if not, write to the Free Software 21: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 22: * USA. 23: * 24: * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 25: * in the United States and other countries.] 26: * 27: * ------------------- 28: * JDBCPieDataset.java 29: * ------------------- 30: * (C) Copyright 2002-2004, by Bryan Scott and Contributors. 31: * 32: * Original Author: Bryan Scott; Andy 33: * Contributor(s): David Gilbert (for Object Refinery Limited); 34: * Thomas Morgner; 35: * 36: * $ Id: $ 37: * 38: * Changes 39: * ------- 40: * 26-Apr-2002 : Creation based on JdbcXYDataSet, but extending 41: * DefaultPieDataset (BS); 42: * 24-Jun-2002 : Removed unnecessary import and local variable (DG); 43: * 13-Aug-2002 : Updated Javadoc comments and imports, removed default 44: * constructor (DG); 45: * 18-Sep-2002 : Updated to support BIGINT (BS); 46: * 21-Jan-2003 : Renamed JdbcPieDataset --> JDBCPieDataset (DG); 47: * 03-Feb-2003 : Added Types.DECIMAL (see bug report 677814) (DG); 48: * 05-Jun-2003 : Updated to support TIME, optimised executeQuery method (BS); 49: * 30-Jul-2003 : Added empty contructor and executeQuery(connection,string) 50: * method (BS); 51: * 02-Dec-2003 : Throwing exceptions allows to handle errors, removed default 52: * constructor, as without a connection, a query can never be 53: * executed (TM); 54: * 04-Dec-2003 : Added missing Javadocs (DG); 55: */ 56: 57: package org.jfree.data.jdbc; 58: 59: import java.sql.Connection; 60: import java.sql.DriverManager; 61: import java.sql.SQLException; 62: import java.sql.Timestamp; 63: import java.sql.Types; 64: import java.sql.ResultSet; 65: import java.sql.ResultSetMetaData; 66: import java.sql.Statement; 67: 68: import org.jfree.data.general.DefaultPieDataset; 69: import org.jfree.data.general.PieDataset; 70: 71: /** 72: * A {@link PieDataset} that reads data from a database via JDBC. 73: * <P> 74: * A query should be supplied that returns data in two columns, the first 75: * containing VARCHAR data, and the second containing numerical data. The 76: * data is cached in-memory and can be refreshed at any time. 77: * 78: * @author Bryan Scott. 79: */ 80: public class JDBCPieDataset extends DefaultPieDataset { 81: 82: /** The database connection. */ 83: private transient Connection connection; 84: 85: /** 86: * Creates a new JDBCPieDataset and establishes a new database connection. 87: * 88: * @param url the URL of the database connection. 89: * @param driverName the database driver class name. 90: * @param user the database user. 91: * @param password the database users password. 92: * 93: * @throws ClassNotFoundException if the driver cannot be found. 94: * @throws SQLException if there is a problem obtaining a database 95: * connection. 96: */ 97: public JDBCPieDataset(String url, 98: String driverName, 99: String user, 100: String password) 101: throws SQLException, ClassNotFoundException { 102: 103: Class.forName(driverName); 104: this.connection = DriverManager.getConnection(url, user, password); 105: } 106: 107: /** 108: * Creates a new JDBCPieDataset using a pre-existing database connection. 109: * <P> 110: * The dataset is initially empty, since no query has been supplied yet. 111: * 112: * @param con the database connection. 113: */ 114: public JDBCPieDataset(Connection con) { 115: if (con == null) { 116: throw new NullPointerException("A connection must be supplied."); 117: } 118: this.connection = con; 119: } 120: 121: 122: /** 123: * Creates a new JDBCPieDataset using a pre-existing database connection. 124: * <P> 125: * The dataset is initialised with the supplied query. 126: * 127: * @param con the database connection. 128: * @param query the database connection. 129: * 130: * @throws SQLException if there is a problem executing the query. 131: */ 132: public JDBCPieDataset(Connection con, String query) throws SQLException { 133: this(con); 134: executeQuery(query); 135: } 136: 137: /** 138: * ExecuteQuery will attempt execute the query passed to it against the 139: * existing database connection. If no connection exists then no action 140: * is taken. 141: * The results from the query are extracted and cached locally, thus 142: * applying an upper limit on how many rows can be retrieved successfully. 143: * 144: * @param query the query to be executed. 145: * 146: * @throws SQLException if there is a problem executing the query. 147: */ 148: public void executeQuery(String query) throws SQLException { 149: executeQuery(this.connection, query); 150: } 151: 152: /** 153: * ExecuteQuery will attempt execute the query passed to it against the 154: * existing database connection. If no connection exists then no action 155: * is taken. 156: * The results from the query are extracted and cached locally, thus 157: * applying an upper limit on how many rows can be retrieved successfully. 158: * 159: * @param query the query to be executed 160: * @param con the connection the query is to be executed against 161: * 162: * @throws SQLException if there is a problem executing the query. 163: */ 164: public void executeQuery(Connection con, String query) throws SQLException { 165: 166: Statement statement = null; 167: ResultSet resultSet = null; 168: 169: try { 170: statement = con.createStatement(); 171: resultSet = statement.executeQuery(query); 172: ResultSetMetaData metaData = resultSet.getMetaData(); 173: 174: int columnCount = metaData.getColumnCount(); 175: if (columnCount != 2) { 176: throw new SQLException( 177: "Invalid sql generated. PieDataSet requires 2 columns only" 178: ); 179: } 180: 181: int columnType = metaData.getColumnType(2); 182: double value = Double.NaN; 183: while (resultSet.next()) { 184: Comparable key = resultSet.getString(1); 185: switch (columnType) { 186: case Types.NUMERIC: 187: case Types.REAL: 188: case Types.INTEGER: 189: case Types.DOUBLE: 190: case Types.FLOAT: 191: case Types.DECIMAL: 192: case Types.BIGINT: 193: value = resultSet.getDouble(2); 194: setValue(key, value); 195: break; 196: 197: case Types.DATE: 198: case Types.TIME: 199: case Types.TIMESTAMP: 200: Timestamp date = resultSet.getTimestamp(2); 201: value = date.getTime(); 202: setValue(key, value); 203: break; 204: 205: default: 206: System.err.println( 207: "JDBCPieDataset - unknown data type" 208: ); 209: break; 210: } 211: } 212: 213: fireDatasetChanged(); 214: 215: } 216: finally { 217: if (resultSet != null) { 218: try { 219: resultSet.close(); 220: } 221: catch (Exception e) { 222: System.err.println("JDBCPieDataset: swallowing exception."); 223: } 224: } 225: if (statement != null) { 226: try { 227: statement.close(); 228: } 229: catch (Exception e) { 230: System.err.println("JDBCPieDataset: swallowing exception."); 231: } 232: } 233: } 234: } 235: 236: 237: /** 238: * Close the database connection 239: */ 240: public void close() { 241: try { 242: this.connection.close(); 243: } 244: catch (Exception e) { 245: System.err.println("JdbcXYDataset: swallowing exception."); 246: } 247: } 248: }