DbTableCommonParameters.java

/**
 * Copyright (C) 2011  JTalks.org Team
 * 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
 */
package org.jtalks.poulpe.util.databasebackup.persistence;

import org.apache.commons.lang.Validate;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;

/**
 * The class is responsible for providing table's common parameters such as database engine, collation etc.
 * 
 * @author Evgeny Surovtsev
 * 
 */
class DbTableCommonParameters {
    /**
     * Constructs a new instance of the class with given DataSource and TableName. These parameters will be used for
     * preparing table's common parameters.
     * 
     * @param dataSource
     *            a DataSource object for accessing the table.
     * @param tableName
     *            a name of the table to be dumped.
     */
    public DbTableCommonParameters(DataSource dataSource, String tableName) {
        Validate.notNull(dataSource, "dataSource parameter must not be null.");
        Validate.notEmpty(tableName, "tableName parameter must not be empty.");
        this.dataSource = dataSource;
        this.tableName = tableName;
    }

    /**
     * Returns common parameters of the table which can be used in the SQL CREATE TABLE statement. A possible list of
     * parameters defined in the OTHER_PARAMETER_MAP.
     * 
     * @return a map of the common table's parameters.
     * @throws SQLException
     *             Is thrown in case any errors during work with database occur.
     */
    public Map<String, String> getParameters() throws SQLException {
        Map<String, String> parameters = new HashMap<String, String>();
        Connection connection = null;
        ResultSet rs = null;
        Statement stmt = null;
        try {
            connection = dataSource.getConnection();
            stmt = connection.createStatement();
            rs = stmt.executeQuery("SHOW TABLE STATUS WHERE Name=" + TableDataUtil.getSqlValueQuotedString(tableName));
            if (rs.next()) {
                for (final String column : OTHER_PARAMETER_MAP.keySet()) {
                    final String value = rs.getString(column);
                    if (value != null) {
                        parameters.put(OTHER_PARAMETER_MAP.get(column), value);
                    }
                }
            }
        } finally {
            if (stmt != null) {
                stmt.close();
            }
            if (rs != null) {
                rs.close();
            }
            if (connection != null) {
                connection.close();
            }
        }

        return parameters;
    }

    private static final Map<String, String> OTHER_PARAMETER_MAP = new HashMap<String, String>();
    static {
        OTHER_PARAMETER_MAP.put("Engine", "ENGINE");
        OTHER_PARAMETER_MAP.put("Collation", "COLLATE");
        OTHER_PARAMETER_MAP.put("Auto_increment", "AUTO_INCREMENT");
    }

    private final String tableName;
    private final DataSource dataSource;
}