Network Programming: to maintain sockets or not?

Question

I\'m currently translating an API from C# to Java which has a network component.

The C# version seems to keep the input and output streams and the socket open for th

Answer 1

I am coming a bit late, but I didn't see anyone suggest that.

I think it will be wise to consider pooling your connections(doesn't matter if Socket or TCP), being able to maintain couple connections open and quickly reuse them in your code base would be optimal in case of performance.

In fact, Roslyn compiler extensively use this technique in a lot of places. https://github.com/dotnet/roslyn/search?l=C%23&q=pooled&type=&utf8=%E2%9C%93

Answer 2

I suggest you look at using an existing messaging solution like ActiveMQ or Netty. This will handle lot of the issues you may find with messaging.

Answer 3

You can also look at DatagramSocket and DatagramPacket. The advantage is lower over-head, the disadvantage is the over-head that regular Socket provides.

Answer 4

There is a trade off between the cost of keeping the connections open and the cost of creating those connections.

Creating connections costs time and bandwidth. You have to do the 3-way TCP handshake, launch a new server thread, ...

Keeping connections open costs mainly memory and connections. Network connections are a resource limited by the OS. If you have too many clients connected, you might run out of available connections. It will cost memory as you will have one thread open for each connection, with its associated state.

The right balanced will be different based on the usage you expect. If you have a lot of clients connecting for short period of times, it's probably gonna be more efficient to close the connections. If you have few clients connecting for long period of time, you should probably keep the connections open ...

Answer 5

If you've only got a single socket on the client and the server, you should keep it open for as long as possible.

Answer 6

It depends on how frequent you expect the user to type in commands. If it happens quite infrequently, you could perhaps close the sockets. If frequent, creating sockets repeatedly can be an expensive operation.

Now having said that, how expensive, in terms of machine resources, is it to have a socket connection open for infrequent data? Why exactly do you think that "maintaining a Socket and output stream for outbound comms is not such a good idea" (even though it seems the right thing to do)? On the other hand, this is different for file streams if you expect that other processes might want to use the same file. Closing the file stream quickly in this case would be the way to go.

How likely is it that you are going to run out of the many TCP connections you can create, which other processes making outbound connections might want to use? Or do you expect to have a large number of clients connecting to your server at a time?