In today’s fast-paced digital world, real-time data synchronization has become a critical requirement for many applications. Whether it’s syncing data between different databases or ensuring data consistency across multiple systems, real-time synchronization is a powerful tool for keeping data up to date in distributed environments.

In this blog post, we will explore how to implement real-time data synchronization using GlassFish, a popular Java application server, and Change Data Capture (CDC) technology. CDC captures and records every change made to a database, allowing applications to react and synchronize data in real time.

Prerequisites

Before we begin, make sure you have the following prerequisites installed:

1. GlassFish application server
2. Java Development Kit (JDK)
3. A database (e.g., Oracle, MySQL, PostgreSQL)

Setting up CDC

First, let’s set up CDC to capture and track data changes in the source database. CDC technology varies depending on the database vendor, so make sure to consult your database documentation for specific instructions.

Once CDC is enabled and configured, it will start recording all changes made to the source database.

Implementing Real-Time Synchronization in Java

Now, let’s dive into the implementation of real-time synchronization using GlassFish and CDC in Java.

Step 1: Creating a Java Web Application

First, create a new Java web application using your preferred IDE. This application will act as the real-time synchronization engine.

Step 2: Configuring GlassFish Connection Pool

Configure a connection pool in GlassFish to connect to both the source and destination databases. This connection pool will be used to retrieve data from the source and update the destination database.

Step 3: Polling CDC Changes through Java

Write a Java class that polls for CDC changes in the source database at regular intervals. This class will use JDBC to connect to the source database and query the CDC logs.

Here is an example code snippet that polls for CDC changes:

import java.sql.*;

public class CDCPoller {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        // Connect to the source database
        Connection sourceConnection = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ORCL", "username", "password");

        // Poll CDC changes
        CallableStatement cdcStatement = sourceConnection.prepareCall("BEGIN DBMS_CDC_SUBSCRIBE.GET_SUBSCRIBED_TABLES(?, ?, ?, ?, ?); END;");
        cdcStatement.setString(1, "username");
        cdcStatement.setString(2, "password");
        cdcStatement.setString(3, "CDC_SCHEMA");
        cdcStatement.setString(4, "TABLE_NAME");
        cdcStatement.registerOutParameter(5, oracle.jdbc.OracleTypes.CURSOR);
        cdcStatement.execute();

        // Process CDC changes
        ResultSet cdcResultSet = (ResultSet) cdcStatement.getObject(5);
        while (cdcResultSet.next()) {
            // Process each CDC change
            // Update destination database with the changes
        }

        // Cleanup
        cdcResultSet.close();
        cdcStatement.close();
        sourceConnection.close();
    }
}

Step 4: Updating the Destination Database

Once CDC changes are retrieved, you can update the destination database with the changes. This step involves inserting, updating, or deleting records in the destination database based on the CDC logs.

Make sure to handle any conflicts or data integrity issues that may arise during the synchronization process.

Conclusion

Implementing real-time data synchronization using GlassFish and Change Data Capture (CDC) in Java can greatly improve the efficiency and accuracy of data synchronization in distributed environments. By leveraging CDC technology and the powerful features of GlassFish, you can ensure that your data remains consistent and up to date across multiple systems.

Remember to adjust the code snippets according to your specific requirements and database configurations. Happy coding!

#realtime #datasync