uk.os.vt.mbtiles.Util.java Source code

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Here is the source code for uk.os.vt.mbtiles.Util.java

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/*
 * Copyright (C) 2016 Ordnance Survey
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package uk.os.vt.mbtiles;

import com.google.common.base.Charsets;
import com.google.common.io.Resources;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

final class Util {

    private static final Logger LOG = LoggerFactory.getLogger(Util.class.getSimpleName());
    private static final int STATEMENT_QUERY_TIMEOUT_IN_SECONDS = 30;

    private Util() {
    }

    /**
     * Provide a freshly initialized mbtiles file.
     *
     * @param file to create and apply mbtiles SQL
     * @throws IOException thrown on IO error
     */
    protected static void initialise(File file) throws IOException {
        LOG.info("initializing: " + file.getAbsolutePath());
        if (file.exists() && !file.delete()) {
            throw new IOException("initialization failure - cannot delete file " + file);
        }
        legacyMaker(file);
    }

    private static Connection getConnection(File file) throws SQLException {
        return getConnection(file.getAbsolutePath());
    }

    private static Connection getConnection(String fileLocation) throws SQLException {
        LOG.info("DB file location " + fileLocation);
        return printMetadata(DriverManager.getConnection("jdbc:sqlite:" + fileLocation));
    }

    /**
     * Legacy from file.
     *
     * <p>Note: please see RxJDBC DatabaseCreator:62 with:
     * public static void createDatabase(Connection c) {
     *
     * @param file the file
     * @throws IOException thrown on IO error
     */
    private static void legacyMaker(File file) throws IOException {
        Connection connection = null;
        try {
            connection = getConnection(file);
            final URL url = Resources.getResource("mbtiles_schema.sql");
            final String sql = Resources.toString(url, Charsets.UTF_8);

            final Statement statement = connection.createStatement();
            statement.setQueryTimeout(STATEMENT_QUERY_TIMEOUT_IN_SECONDS);
            statement.executeUpdate(sql); // replaced statement.execute(text); because multi statement SQL
            statement.close();
        } catch (IOException | SQLException ex) {
            throw new IOException("cannot produce a valid MBTiles file", ex);
        } finally {
            try {
                if (connection != null) {
                    connection.close();
                }
            } catch (final SQLException ex) {
                // connection close failed.
                LOG.error("cannot close connection", ex);
            }
        }
    }

    // TODO remove when issues ironed out
    private static Connection printMetadata(Connection connection) throws SQLException {
        final DatabaseMetaData meta = connection.getMetaData();
        LOG.info("Using driver: " + meta.getDriverName());
        return connection;
    }
}