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Java example source code file (JDBCAdapter.java)

This example Java source code file (JDBCAdapter.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, boolean, class, classnotfoundexception, connection, jdbc, jdbcadapter, jtable, list, object, override, sql, sqlexception, statement, string, suppresswarnings, table, this, util

The JDBCAdapter.java Java example source code

/*
 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */



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.Types;
import java.util.ArrayList;
import java.util.List;
import javax.swing.table.AbstractTableModel;


/**
 * An adaptor, transforming the JDBC interface to the TableModel interface.
 *
 * @author Philip Milne
 */
@SuppressWarnings("serial")
public class JDBCAdapter extends AbstractTableModel {

    Connection connection;
    Statement statement;
    ResultSet resultSet;
    String[] columnNames = {};
    List<List rows = new ArrayList>();
    ResultSetMetaData metaData;

    public JDBCAdapter(String url, String driverName,
            String user, String passwd) {
        try {
            Class.forName(driverName);
            System.out.println("Opening db connection");

            connection = DriverManager.getConnection(url, user, passwd);
            statement = connection.createStatement();
        } catch (ClassNotFoundException ex) {
            System.err.println("Cannot find the database driver classes.");
            System.err.println(ex);
        } catch (SQLException ex) {
            System.err.println("Cannot connect to this database.");
            System.err.println(ex);
        }
    }

    public void executeQuery(String query) {
        if (connection == null || statement == null) {
            System.err.println("There is no database to execute the query.");
            return;
        }
        try {
            resultSet = statement.executeQuery(query);
            metaData = resultSet.getMetaData();

            int numberOfColumns = metaData.getColumnCount();
            columnNames = new String[numberOfColumns];
            // Get the column names and cache them.
            // Then we can close the connection.
            for (int column = 0; column < numberOfColumns; column++) {
                columnNames[column] = metaData.getColumnLabel(column + 1);
            }

            // Get all rows.
            rows = new ArrayList<List();
            while (resultSet.next()) {
                List<Object> newRow = new ArrayList();
                for (int i = 1; i <= getColumnCount(); i++) {
                    newRow.add(resultSet.getObject(i));
                }
                rows.add(newRow);
            }
            //  close(); Need to copy the metaData, bug in jdbc:odbc driver.

            // Tell the listeners a new table has arrived.
            fireTableChanged(null);
        } catch (SQLException ex) {
            System.err.println(ex);
        }
    }

    public void close() throws SQLException {
        System.out.println("Closing db connection");
        resultSet.close();
        statement.close();
        connection.close();
    }

    @Override
    protected void finalize() throws Throwable {
        close();
        super.finalize();
    }

    //////////////////////////////////////////////////////////////////////////
    //
    //             Implementation of the TableModel Interface
    //
    //////////////////////////////////////////////////////////////////////////
    // MetaData
    @Override
    public String getColumnName(int column) {
        if (columnNames[column] != null) {
            return columnNames[column];
        } else {
            return "";
        }
    }

    @Override
    public Class<?> getColumnClass(int column) {
        int type;
        try {
            type = metaData.getColumnType(column + 1);
        } catch (SQLException e) {
            return super.getColumnClass(column);
        }

        switch (type) {
            case Types.CHAR:
            case Types.VARCHAR:
            case Types.LONGVARCHAR:
                return String.class;

            case Types.BIT:
                return Boolean.class;

            case Types.TINYINT:
            case Types.SMALLINT:
            case Types.INTEGER:
                return Integer.class;

            case Types.BIGINT:
                return Long.class;

            case Types.FLOAT:
            case Types.DOUBLE:
                return Double.class;

            case Types.DATE:
                return java.sql.Date.class;

            default:
                return Object.class;
        }
    }

    @Override
    public boolean isCellEditable(int row, int column) {
        try {
            return metaData.isWritable(column + 1);
        } catch (SQLException e) {
            return false;
        }
    }

    public int getColumnCount() {
        return columnNames.length;
    }

    // Data methods
    public int getRowCount() {
        return rows.size();
    }

    public Object getValueAt(int aRow, int aColumn) {
        List<Object> row = rows.get(aRow);
        return row.get(aColumn);
    }

    public String dbRepresentation(int column, Object value) {
        int type;

        if (value == null) {
            return "null";
        }

        try {
            type = metaData.getColumnType(column + 1);
        } catch (SQLException e) {
            return value.toString();
        }

        switch (type) {
            case Types.INTEGER:
            case Types.DOUBLE:
            case Types.FLOAT:
                return value.toString();
            case Types.BIT:
                return ((Boolean) value).booleanValue() ? "1" : "0";
            case Types.DATE:
                return value.toString(); // This will need some conversion.
            default:
                return "\"" + value.toString() + "\"";
        }

    }

    @Override
    public void setValueAt(Object value, int row, int column) {
        try {
            String tableName = metaData.getTableName(column + 1);
            // Some of the drivers seem buggy, tableName should not be null.
            if (tableName == null) {
                System.out.println("Table name returned null.");
            }
            String columnName = getColumnName(column);
            String query =
                    "update " + tableName + " set " + columnName + " = "
                    + dbRepresentation(column, value) + " where ";
            // We don't have a model of the schema so we don't know the
            // primary keys or which columns to lock on. To demonstrate
            // that editing is possible, we'll just lock on everything.
            for (int col = 0; col < getColumnCount(); col++) {
                String colName = getColumnName(col);
                if (colName.equals("")) {
                    continue;
                }
                if (col != 0) {
                    query = query + " and ";
                }
                query = query + colName + " = " + dbRepresentation(col,
                        getValueAt(row, col));
            }
            System.out.println(query);
            System.out.println("Not sending update to database");
            // statement.executeQuery(query);
        } catch (SQLException e) {
            //     e.printStackTrace();
            System.err.println("Update failed");
        }
        List<Object> dataRow = rows.get(row);
        dataRow.set(column, value);

    }
}




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