org.jfree.data.jdbc.JDBCPieDataset Maven / Gradle / Ivy
/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-present, by David Gilbert and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* -------------------
* JDBCPieDataset.java
* -------------------
* (C) Copyright 2002-present, by Bryan Scott and Contributors.
*
* Original Author: Bryan Scott; Andy
* Contributor(s): David Gilbert;
* Thomas Morgner;
*
*/
package org.jfree.data.jdbc;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.sql.Types;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.general.PieDataset;
/**
* A {@link PieDataset} that reads data from a database via JDBC.
*
* A query should be supplied that returns data in two columns, the first
* containing VARCHAR data, and the second containing numerical data. The
* data is cached in-memory and can be refreshed at any time.
*/
public class JDBCPieDataset extends DefaultPieDataset {
/** For serialization. */
static final long serialVersionUID = -8753216855496746108L;
/** The database connection. */
private transient Connection connection;
/**
* Creates a new JDBCPieDataset and establishes a new database connection.
*
* @param url the URL of the database connection.
* @param driverName the database driver class name.
* @param user the database user.
* @param password the database users password.
*
* @throws ClassNotFoundException if the driver cannot be found.
* @throws SQLException if there is a problem obtaining a database
* connection.
*/
public JDBCPieDataset(String url,
String driverName,
String user,
String password)
throws SQLException, ClassNotFoundException {
Class.forName(driverName);
this.connection = DriverManager.getConnection(url, user, password);
}
/**
* Creates a new JDBCPieDataset using a pre-existing database connection.
*
* The dataset is initially empty, since no query has been supplied yet.
*
* @param con the database connection.
*/
public JDBCPieDataset(Connection con) {
if (con == null) {
throw new NullPointerException("A connection must be supplied.");
}
this.connection = con;
}
/**
* Creates a new JDBCPieDataset using a pre-existing database connection.
*
* The dataset is initialised with the supplied query.
*
* @param con the database connection.
* @param query the database connection.
*
* @throws SQLException if there is a problem executing the query.
*/
public JDBCPieDataset(Connection con, String query) throws SQLException {
this(con);
executeQuery(query);
}
/**
* ExecuteQuery will attempt execute the query passed to it against the
* existing database connection. If no connection exists then no action
* is taken.
* The results from the query are extracted and cached locally, thus
* applying an upper limit on how many rows can be retrieved successfully.
*
* @param query the query to be executed.
*
* @throws SQLException if there is a problem executing the query.
*/
public void executeQuery(String query) throws SQLException {
executeQuery(this.connection, query);
}
/**
* ExecuteQuery will attempt execute the query passed to it against the
* existing database connection. If no connection exists then no action
* is taken.
* The results from the query are extracted and cached locally, thus
* applying an upper limit on how many rows can be retrieved successfully.
*
* @param query the query to be executed
* @param con the connection the query is to be executed against
*
* @throws SQLException if there is a problem executing the query.
*/
public void executeQuery(Connection con, String query) throws SQLException {
Statement statement = null;
ResultSet resultSet = null;
try {
statement = con.createStatement();
resultSet = statement.executeQuery(query);
ResultSetMetaData metaData = resultSet.getMetaData();
int columnCount = metaData.getColumnCount();
if (columnCount != 2) {
throw new SQLException(
"Invalid sql generated. PieDataSet requires 2 columns only"
);
}
int columnType = metaData.getColumnType(2);
double value;
while (resultSet.next()) {
Comparable key = resultSet.getString(1);
switch (columnType) {
case Types.NUMERIC:
case Types.REAL:
case Types.INTEGER:
case Types.DOUBLE:
case Types.FLOAT:
case Types.DECIMAL:
case Types.BIGINT:
value = resultSet.getDouble(2);
setValue(key, value);
break;
case Types.DATE:
case Types.TIME:
case Types.TIMESTAMP:
Timestamp date = resultSet.getTimestamp(2);
value = date.getTime();
setValue(key, value);
break;
default:
System.err.println(
"JDBCPieDataset - unknown data type");
break;
}
}
fireDatasetChanged();
}
finally {
if (resultSet != null) {
try {
resultSet.close();
}
catch (Exception e) {
System.err.println("JDBCPieDataset: swallowing exception.");
}
}
if (statement != null) {
try {
statement.close();
}
catch (Exception e) {
System.err.println("JDBCPieDataset: swallowing exception.");
}
}
}
}
/**
* Close the database connection
*/
public void close() {
try {
this.connection.close();
}
catch (Exception e) {
System.err.println("JdbcXYDataset: swallowing exception.");
}
}
}