source: gs3-extensions/maori-lang-detection/src/org/greenstone/atea/MongoDBAccess.java@ 33623

package org.greenstone.atea;


import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

import org.bson.Document;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.Properties;

import org.apache.log4j.Logger;


/** 
 * https://www.tutorialspoint.com/mongodb/mongodb_java.htm
 *
 * TO COMPILE:
 *    maori-lang-detection/src$
 *       javac -cp ".:../conf:../lib/*" org/greenstone/atea/MongoDBAccess.java
 *
 * TO RUN:
 *       java -cp ".:../conf:../lib/*" org.greenstone.atea.MongoDBAccess
 *
 * Manually connecting to mongodb from client:
 *    mongo 'mongodb://mongodb.cms.waikato.ac.nz:27017' -u USERNAME -p
 * Then after connecting with pwd, type:
 *    use DBNAME
 *
 * Or connect to mongodb and specify db in one statement:
 *    mongo 'mongodb://mongodb.cms.waikato.ac.nz:27017/DBNAME?authSource=admin' -u USERNAME -p
 *
 * Some links:
 *   - https://stackoverflow.com/questions/19938153/do-i-need-to-explicitly-close-connection
 *   - https://docs.mongodb.com/manual/reference/glossary/ (particularly "collection")
 *   - https://tecadmin.net/tutorial/mongodb/drop-collection/
 * IMPORTANT LINK:
 *   - https://www.mongodb.com/blog/post/6-rules-of-thumb-for-mongodb-schema-design-part-1
 *
 */
public class MongoDBAccess {

    private static Logger logger = Logger.getLogger(org.greenstone.atea.MongoDBAccess.class.getName());
    
    String HOST = "localhost";
    int PORT = 27017; // mongodb port
    String PROPS_FILENAME = "config.properties";
    String DB_NAME = "ateacrawldata";
    
    private String USERNAME;
    private String PASSWORD;


    private MongoClient mongo = null;
    private MongoDatabase database = null;
    
    public MongoDBAccess() throws Exception {
    boolean success = false;
    
    // Read in the username and password from our props file
    Properties props = new Properties();

    //File propsFile = new File(PROPS_FILENAME);
    //logger.debug("*** Conf props filename: " + propsFile.getAbsolutePath());
    try {
        props.load(getClass().getClassLoader().getResourceAsStream(PROPS_FILENAME));        
    } catch(Exception e) {
        logger.error(e);
    }
    
    
    USERNAME = props.getProperty("mongodb.user", "");
    if(USERNAME.equals("")) {
        USERNAME = "root";
        logger.warn("WARNING: No sensible value for mongodb.user specified in " + PROPS_FILENAME + ". Attempting to use: " + USERNAME);
            }
    PASSWORD = props.getProperty("mongodb.pwd");

    logger.debug("Got pwd: " + PASSWORD);
    
    if(PASSWORD != null && PASSWORD.equals("CHANGEME")) {
        
        success = false;
        throw new Exception("************ FATAL ERROR: Change DB password in properties file " + PROPS_FILENAME);       
    }

    HOST = props.getProperty("mongodb.host", HOST);
    String port = props.getProperty("mongodb.port", Integer.toString(PORT));
    PORT = Integer.parseInt(port);
    DB_NAME = props.getProperty("mongodb.dbname", DB_NAME);

    logger.info("Connecting to mongodb with:");
    logger.info(" - host:    " + HOST);
    logger.info(" - port:    " + PORT);
    logger.info(" - user:    " + USERNAME);
    logger.info(" - db name: " + DB_NAME);  
    }

    /** 
     * Since we have only a single MongoClient, don't need to call close/disconnect on it as per
     * https://stackoverflow.com/questions/19938153/do-i-need-to-explicitly-close-connection
     */
    public void connectToDB() throws Exception {
    // Creating a Mongo client 
    mongo = new MongoClient( HOST, PORT ); 
    
    // Creating Credentials 
    MongoCredential credential; 
    credential = MongoCredential.createCredential(USERNAME, DB_NAME, PASSWORD.toCharArray()); 
    System.out.println("Connected to the database successfully");  
    
    // Accessing the database 
    database = mongo.getDatabase(DB_NAME); 
    logger.info("Credentials: "+ credential);
    }
    

    /*
    public void insertDocument() {
    MongoCollection<Document> collection = this.database.getCollection("sampleCollection");
    }
    */

    // create collection (table in RDBMS) websites, create collection webpages
    // webpages collection will have sentences embedded
    
    public static void main(String args[]) {
    try {
        MongoDBAccess mongodbCon = new MongoDBAccess();
        mongodbCon.connectToDB();
        //mongodbCon.insertDocument();
    }catch(Exception e) {
        e.printStackTrace();
    }
    }
}