vaadin-framework/src/com/itmill/toolkit/demo/util/SampleDatabase.java

/* 
@ITMillApache2LicenseForJavaFiles@
 */

package com.itmill.toolkit.demo.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * Creates temporary database named toolkit with sample table named employee and
 * populates it with data. By default we use HSQLDB. Ensure that you have
 * hsqldb.jar under WEB-INF/lib directory. Database is will be created into
 * memory.
 * 
 * @author IT Mill Ltd.
 * 
 */
public class SampleDatabase {

    public static final int ROWCOUNT = 1000;

    private Connection connection = null;

    private static final String[] firstnames = new String[] { "Amanda",
            "Andrew", "Bill", "Frank", "Matt", "Xavier", "John", "Mary", "Joe",
            "Gloria", "Marcus", "Belinda", "David", "Anthony", "Julian",
            "Paul", "Carrie", "Susan", "Gregg", "Michael", "William", "Ethan",
            "Thomas", "Oscar", "Norman", "Roy", "Sarah", "Jeff", "Jane",
            "Peter", "Marc", "Josie", "Linus" };

    private static final String[] lastnames = new String[] { "Torvalds",
            "Smith", "Jones", "Beck", "Burton", "Bell", "Davis", "Burke",
            "Bernard", "Hood", "Scott", "Smith", "Carter", "Roller", "Conrad",
            "Martin", "Fisher", "Martell", "Freeman", "Hackman", "Jones",
            "Harper", "Russek", "Johnson", "Sheridan", "Hill", "Parker",
            "Foster", "Moss", "Fielding" };

    private static final String[] titles = new String[] { "Project Manager",
            "Marketing Manager", "Sales Manager", "Sales", "Trainer",
            "Technical Support", "Account Manager", "Customer Support",
            "Testing Engineer", "Software Designer", "Programmer", "Consultant" };

    private static final String[] units = new String[] { "Tokyo",
            "Mexico City", "Seoul", "New York", "Sao Paulo", "Bombay", "Delhi",
            "Shanghai", "Los Angeles", "London", "Shanghai", "Sydney",
            "Bangalore", "Hong Kong", "Madrid", "Milano", "Beijing", "Paris",
            "Moscow", "Berlin", "Helsinki" };

    /**
     * Create temporary database.
     * 
     */
    public SampleDatabase() {
        // connect to SQL database
        connect();

        // initialize SQL database
        createTables();

        // test by executing sample JDBC query
        testDatabase();
    }

    /**
     * Creates sample table named employee and populates it with data.Use the
     * specified database connection.
     * 
     * @param connection
     */
    public SampleDatabase(Connection connection) {
        // initialize SQL database
        createTables();

        // test by executing sample JDBC query
        testDatabase();
    }

    /**
     * Connect to SQL database. In this sample we use HSQLDB and an toolkit
     * named database in implicitly created into system memory.
     * 
     */
    private void connect() {
        // use memory-Only Database
        final String url = "jdbc:hsqldb:mem:toolkit";
        try {
            Class.forName("org.hsqldb.jdbcDriver").newInstance();
            connection = DriverManager.getConnection(url, "sa", "");
        } catch (final Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * use for SQL commands CREATE, DROP, INSERT and UPDATE
     * 
     * @param expression
     * @throws SQLException
     */
    public void update(String expression) throws SQLException {
        Statement st = null;
        st = connection.createStatement();
        final int i = st.executeUpdate(expression);
        if (i == -1) {
            throw new SQLException("Database error : " + expression);
        }
        st.close();
    }

    /**
     * Create test table and few rows. Issue note: using capitalized column
     * names as HSQLDB returns column names in capitalized form with this demo.
     * 
     */
    private void createTables() {
        try {
            String stmt = null;
            stmt = "CREATE TABLE employee ( ID INTEGER IDENTITY, FIRSTNAME VARCHAR(100), "
                    + "LASTNAME VARCHAR(100), TITLE VARCHAR(100), UNIT VARCHAR(100) )";
            update(stmt);
            for (int j = 0; j < ROWCOUNT; j++) {
                stmt = "INSERT INTO employee(FIRSTNAME, LASTNAME, TITLE, UNIT) VALUES ("
                        + "'"
                        + firstnames[(int) (Math.random() * (firstnames.length - 1))]
                        + "',"
                        + "'"
                        + lastnames[(int) (Math.random() * (lastnames.length - 1))]
                        + "',"
                        + "'"
                        + titles[(int) (Math.random() * (titles.length - 1))]
                        + "',"
                        + "'"
                        + units[(int) (Math.random() * (units.length - 1))]
                        + "'" + ")";
                update(stmt);
            }
        } catch (final SQLException e) {
            if (e.toString().indexOf("Table already exists") == -1) {
                throw new RuntimeException(e);
            }
        }
    }

    /**
     * Test database connection with simple SELECT command.
     * 
     */
    private String testDatabase() {
        String result = null;
        try {
            final Statement stmt = connection.createStatement(
                    ResultSet.TYPE_SCROLL_INSENSITIVE,
                    ResultSet.CONCUR_UPDATABLE);
            final ResultSet rs = stmt
                    .executeQuery("SELECT COUNT(*) FROM employee");
            rs.next();
            result = "rowcount for table test is " + rs.getObject(1).toString();
            stmt.close();
        } catch (final SQLException e) {
            throw new RuntimeException(e);
        }
        return result;
    }

    public Connection getConnection() {
        return connection;
    }

}