Implementing Java RMI with Apache Thrift

14 Sep 2023

Java RMI (Remote Method Invocation) is a popular framework used for implementing distributed systems in Java. It allows Java objects to invoke methods on remote objects, making it easier to build distributed applications. On the other hand, Apache Thrift is a framework that provides cross-language support for building scalable and efficient services. In this blog post, we will explore how to incorporate Java RMI with Apache Thrift to leverage the benefits of both frameworks.

Getting Started

Before we dive into the implementation details, let’s make sure we have the necessary tools and libraries installed:

Java Development Kit (JDK)
Apache Thrift

Step 1: Define the Service Interface

First, we need to define the service interface that will be used by both the client and server. The service interface should include the methods that the client can invoke remotely. Here’s an example:

public interface MyService {
    String getMessage() throws RemoteException;
    int addNumbers(int num1, int num2) throws RemoteException;
}

Step 2: Implement the Service

Next, we need to implement the service interface. This implementation will be used by the server to handle the remote method invocations from the client. Here’s a sample implementation:

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;

public class MyServiceImpl extends UnicastRemoteObject implements MyService {
    
    protected MyServiceImpl() throws RemoteException {
        super();
    }

    @Override
    public String getMessage() throws RemoteException {
        return "Hello from the server!";
    }

    @Override
    public int addNumbers(int num1, int num2) throws RemoteException {
        return num1 + num2;
    }
}

Step 3: Generate the Thrift IDL

Now we need to define the Thrift IDL (Interface Definition Language) file. This file specifies the service, methods, and data structures that will be used by the Thrift compiler to generate the necessary code. Here’s an example:

namespace java com.example.service

service MyThriftService {
    string getMessage()
    i32 addNumbers(1: i32 num1, 2: i32 num2)
}

Step 4: Generate the Java Code

Using the Thrift compiler, we can generate the Java code from the Thrift IDL file. Run the following command in the terminal:

thrift --gen java myservice.thrift

This command will generate the necessary Java files that will be used by the client and server.

Step 5: Modify the Server and Client

Now, we need to modify the server and client code to use the generated Thrift code. Here’s an example of how to do it:

Server:

import com.example.service.*;

public class Server {
    public static void main(String[] args) {
        try {
            MyServiceImpl serviceImpl = new MyServiceImpl();
            MyThriftService.Processor<MyServiceImpl> processor = new MyThriftService.Processor<>(serviceImpl);
    
            TServerTransport serverTransport = new TServerSocket(9090);
            TServer server = new TSimpleServer(new TServer.Args(serverTransport).processor(processor));
    
            System.out.println("Starting the server...");
            server.serve();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

Client:

import com.example.service.*;

public class Client {
    public static void main(String[] args) {
        try {
            TTransport transport = new TSocket("localhost", 9090);
            transport.open();

            TProtocol protocol = new TBinaryProtocol(transport);
            MyThriftService.Client client = new MyThriftService.Client(protocol);

            String message = client.getMessage();
            System.out.println("Message from server: " + message);

            int result = client.addNumbers(5, 3);
            System.out.println("Addition result: " + result);

            transport.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

Conclusion

By combining Java RMI with Apache Thrift, we can take advantage of the simplicity and ease of use of Java RMI alongside the scalability and cross-language support provided by Apache Thrift. This allows us to build distributed systems that are both efficient and flexible. Experiment with this integration and explore the full potential of utilizing these frameworks together.

#JavaRMI #ApacheThrift