Getting Memcached Version in Java (Detailed Guide w/ Code Examples)

Use Case(s)

Getting the version of Memcached server can be useful while debugging or for logging purposes. It helps developers ensure that they are using a compatible version, and keep track of the server status.

Code Examples

Java Memcached client libraries like Xmemcached and Spymemcached provide ways to get the Memcached server version. Here are examples for each:

1. Using Xmemcached:

import net.rubyeye.xmemcached.MemcachedClient;
import net.rubyeye.xmemcached.XMemcachedClientBuilder;

public class Main {
    public static void main(String[] args) {
        try {
            XMemcachedClientBuilder builder = new XMemcachedClientBuilder("localhost:11211");
            MemcachedClient client = builder.build();

            Map<SocketAddresses, String> versions = client.getVersions();
            System.out.println(versions);
   
            client.shutdown();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this code, we first create a XMemcachedClientBuilder with the address of the Memcached server. Using the builder, we create a MemcachedClient, which is used to interact with the server. The getVersions() method retrieves the version for all connected Memcached servers.

2. Using Spymemcached:

import net.spy.memcached.MemcachedClient;

public class Main {
    public static void main(String[] args) {
        try {
            MemcachedClient client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
            
            Map<SocketAddress, Map<String, String>> stats = client.getStats();
            for (Map.Entry<SocketAddress, Map<String, String>> entry : stats.entrySet()) {
                System.out.println(entry.getKey() + ": " + entry.getValue().get("version"));
            }
            
            client.shutdown();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this code, we create a MemcachedClient with the server address. The getStats() method retrieves statistics from all connected Memcached servers which includes the version.

Best Practices

• Always ensure to close the MemcachedClient after using it to free up resources.
• Handle exceptions properly when creating the client or retrieving the version. Network or server issues can lead to IOExceptions.

Common Mistakes

• Not handling potential IOExceptions. Networking operations are always prone to exceptions, so always include adequate exception handling.
• Using an incorrect server address or port number. Ensure these details match your Memcached server's configuration.

FAQs

1. How can I connect to a Memcached server running on a different machine?

You can replace 'localhost' in the examples above with the IP address or hostname of the machine where Memcached server is running.

2. What if my application connects to multiple Memcached servers?

The getVersions() and getStats() methods return information for all connected servers. You can iterate over the returned map to get data for each server.