armenak / DataDefender

 * Copyright 2014, Armenak Grigoryan, and individual contributors as indicated

 * by the @authors tag. See the copyright.txt in the distribution for a

 * full listing of individual contributors.

 *

 * This 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 software 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.

 */

package com.strider.datadefender.database;

import java.lang.reflect.InvocationTargetException;

import java.sql.Connection;

import java.sql.SQLException;

import com.strider.datadefender.DataDefenderException;

import com.strider.datadefender.DbConfig;

import com.strider.datadefender.DbConfig.Vendor;

import com.strider.datadefender.database.metadata.IMetaData;

import com.strider.datadefender.database.metadata.MetaData;

import com.strider.datadefender.database.metadata.MySqlMetaData;

import com.strider.datadefender.database.sqlbuilder.ISqlBuilder;

import com.strider.datadefender.database.sqlbuilder.SqlBuilder;

import com.strider.datadefender.database.sqlbuilder.MsSqlBuilder;

import com.strider.datadefender.database.sqlbuilder.OracleSqlBuilder;

import com.strider.datadefender.utils.ICloseableNoException;

import lombok.extern.log4j.Log4j2;

/**

 * Aggregate all the various db factories.

 *

 * Will handle the 'pooling' of connections (currently only one).

 *

 * All clients should close the connection by calling the close() method of the

 * AutoCloseable interface.

 *

 * @author Akira Matsuo

 */

public interface IDbFactory extends ICloseableNoException {

    ISqlBuilder createSQLBuilder() throws DataDefenderException;

    IMetaData fetchMetaData() throws DataDefenderException;

    Connection getConnection();

    Connection getUpdateConnection();

    /**

     * Implements the common logic of getting/closing database connections

     */

    @Log4j2

    static abstract class DbFactory implements IDbFactory {

        private final Connection connection;

        protected Connection updateConnection;

        private final Vendor vendor;

        DbFactory(Vendor vendorName) throws DataDefenderException {

            log.info("Connecting to database");

            connection = createConnection();

            updateConnection = connection;

            vendor = vendorName;

        }

        @Override

        public void close() {

            if (connection != null) {

                try {

                    connection.close();

                } catch (SQLException e) {

                    log.error(e.getMessage(), e);

                }

            }

            if (updateConnection != null && updateConnection != connection) {

                try {

                    updateConnection.close();

                } catch (SQLException e) {

                    log.error(e.getMessage(), e);

                }

            }

        }

        public abstract Connection createConnection() throws DataDefenderException;

        @Override

        public Connection getConnection() {

            return connection;

        }

        @Override

        public Connection getUpdateConnection() {

            return updateConnection;

        }

        @Override

        public String getVendorName() {

            return vendor.name();

        }

    }

    /**

     * Generic method handling creation of a DBFactory anonymous instance for

     * supported database vendors.

     *

     * @param <D>

     * @param <M>

     * @param <S>

     * @param config

     * @param connection

     * @param metaData

     * @param builder

     * @return

     * @throws DataDefenderException

     */

    private static <D extends IDbConnection, M extends IMetaData, S extends ISqlBuilder> DbFactory getFactoryWith(

        final DbConfig config,

        Class<D> connection,

        Class<M> metaData,

        Class<S> builder

    ) throws DataDefenderException {

        return new DbFactory(config.getVendor()) {

            @Override

            public Connection createConnection() throws DataDefenderException {

                try {

                    return connection.getConstructor(DbConfig.class).newInstance(config).connect();

                } catch (NoSuchMethodException|InstantiationException|IllegalAccessException|InvocationTargetException e) {

                    throw new DataDefenderException("", e);

                }

            }

            @Override

            public IMetaData fetchMetaData() throws DataDefenderException {

                try {

                    return metaData.getConstructor(DbConfig.class, Connection.class).newInstance(config, getConnection());

                } catch (NoSuchMethodException|InstantiationException|IllegalAccessException|InvocationTargetException e) {

                    throw new DataDefenderException("", e);

                }

            }

            @Override

            public ISqlBuilder createSQLBuilder() throws DataDefenderException {

                try {

                    return builder.getConstructor(DbConfig.class).newInstance(config);

                } catch (NoSuchMethodException|InstantiationException|IllegalAccessException|InvocationTargetException e) {

                    throw new DataDefenderException("", e);

                }

            }

        };

    }

    /**

     * Creates and returns an IDBFactory instance for the given rdbms.

     *

     * @param config

     * @return db factory instance

     * @throws DatabaseAnonymizerException

     */

    public static IDbFactory get(final DbConfig config) throws DataDefenderException {

        if (config.getVendor() == Vendor.MYSQL || config.getVendor() == Vendor.H2) {

            DbFactory factory = getFactoryWith(config, DbConnection.class, MySqlMetaData.class, SqlBuilder.class);

            // create separate connection for updates

            factory.updateConnection = factory.createConnection();

            return factory;

        } else if (config.getVendor() == Vendor.SQLSERVER) {

            return getFactoryWith(config, MsSqlDbConnection.class, MetaData.class, MsSqlBuilder.class);

        } else if (config.getVendor() == Vendor.ORACLE) {

            return getFactoryWith(config, DbConnection.class, MetaData.class, OracleSqlBuilder.class);

        } else if (config.getVendor() == Vendor.POSTGRESQL) {

            return getFactoryWith(config, DbConnection.class, MetaData.class, SqlBuilder.class);

        }

        throw new IllegalArgumentException("Database " + config.getVendor() + " is not supported");

    }

}