no.ntnu.idi.freerider.backend.DBConfigurator.java Source code

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Here is the source code for no.ntnu.idi.freerider.backend.DBConfigurator.java

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/*******************************************************************************
 * @contributor(s): Freerider Team (Group 4, IT2901 Fall 2012, NTNU)
 * @contributor(s): Freerider Team 2 (Group 3, IT2901 Spring 2013, NTNU)
 * @version: 2.0
 * 
 * Copyright 2013 Freerider Team 2
 * 
 * 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 no.ntnu.idi.freerider.backend;

import java.io.File;
import java.util.Calendar;
import java.util.GregorianCalendar;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

/** 
 * A configurator for DBConnector, which reads the details of the database connection from an XML file. */
public final class DBConfigurator {
    private static Calendar lastRead = null;
    private static File configFile;
    private static String DB_URL;
    private static String DB_USERNAME;
    private static String DB_PASSWORD;

    private static void update() {
        if (configFile == null || !configFile.exists()) {
            throw new RuntimeException("No database config file found.");
        }
        if (lastRead == null || configFile.lastModified() > lastRead.getTimeInMillis()) {
            reloadFields();
        }
    }

    private static void reloadFields() {
        try {
            Document document = null;
            document = new SAXReader().read(configFile);
            lastRead = new GregorianCalendar();
            Element root = document.getRootElement();
            Element dbUrlElement = root.element("DATABASE_URL");
            DB_URL = dbUrlElement.getTextTrim();
            Element dbUserNameElement = root.element("DATABASE_USERNAME");
            DB_USERNAME = dbUserNameElement.getTextTrim();
            Element dbPasswordElement = root.element("DATABASE_PASSWORD");
            DB_PASSWORD = dbPasswordElement.getTextTrim();
        } catch (Exception e) {
            throw new RuntimeException("Error reading configuration file.", e);
        }
    }

    /** Retrieve database URL. */
    public static String getDatabaseUrl() {
        update();
        return DB_URL;
    }

    /** Retrieve database username. */
    public static String getDatabaseUsername() {
        update();
        return DB_USERNAME;
    }

    /** Retrieve database password. */
    public static String getDatabasePassword() {
        update();
        return DB_PASSWORD;
    }

    /** Identify the config file. */
    public static void init(File configfile) {
        configFile = configfile;
    }

    /** Identify the path to the config file. */
    public static void init(String configPath) {
        configFile = new File(configPath);
    }
}