AbstractDBHelper.java

/*
 *
 *  Copyright 2014 http://Bither.net
 *
 *  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 net.bither.db;

import java.io.File;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public abstract class AbstractDBHelper {

    private Connection conn;

    private String dbFileFullName;
    protected String connectionString;

    public AbstractDBHelper(String dbDir) {
        this.dbFileFullName = dbDir + File.separator + getDBName();
        this.connectionString = "jdbc:sqlite:" + dbFileFullName;
    }


    protected abstract String getDBName();

    protected abstract int currentVersion();

    protected abstract int dbVersion();

    protected abstract void onCreate(Connection conn) throws SQLException;

    protected abstract void onUpgrade(Connection conn, int newVersion, int oldVerion) throws SQLException;

    public Connection getConn() {
        return conn;
    }

    public void initDb() {
        try {
            Class.forName("org.sqlite.JDBC");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
        try {
            conn = DriverManager.getConnection(this.connectionString, null, null);
            conn.setAutoCommit(false);
            int dbVersion = dbVersion();
            int cuerrentVersion = currentVersion();
            if (dbVersion == 0) {
                onCreate(conn);
            } else if (dbVersion() < cuerrentVersion) {
                onUpgrade(conn, cuerrentVersion, dbVersion);
            }
        } catch (SQLException e) {
            File file = new File(dbFileFullName);
            if (file.exists()) {
                file.delete();
            }
            e.printStackTrace();
        }
    }


    public PreparedStatement getPreparedStatement(String sql, String[] arg) throws SQLException {
        PreparedStatement stmt = conn.prepareStatement(sql);
        if (arg != null) {
            for (int i = 0; i < arg.length; i++) {
                stmt.setString(i + 1, arg[i]);
            }
        }
        return stmt;

    }

    public boolean executeUpdate(String sql, String[] arg) {

        try {
            PreparedStatement stmt = conn.prepareStatement(sql);
            if (arg != null) {
                for (int i = 0; i < arg.length; i++) {
                    stmt.setString(i + 1, arg[i]);
                }
            }
            stmt.executeUpdate();
            conn.commit();
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
        return true;
    }


    public void close() {
        try {
            if (conn != null) {
                conn.close();
                conn = null;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}