My application instance has both client and server.
and now,there are 4 instances running.
Currently in each instance server uses nio multiplexing to accept and broadcast data.
When client writes to channel and if server reply with some data.Client wait for output from server.
Is it possible to use nio at client side ?
If yes can anybody give me some pointers regarding same ?
You can use NIO on client side. I recommend using JBoss Netty for NIO processing, you may see client example in it's docs.
It is possible of course to use NIO on the client side but there is rarely much point unless your client deals with hundreds of connections, which is pretty rare. It might have a point in a Web crawler for example.
Related
Both grpc-java and grpc-c++ have the support for in-process channel, which is used if grpc client and server are in the same process.
So I have a question, is it possible to use java client to call c++ server in the same process using in-process channel?
No. The inprocess channels in each language are language-specific. You would need to use a normal channel and a port of localhost.
While it might be possible to use socketpair() to do something similar, it would require some effort to get working.
I have a requirement where I need to send message from multiple clients and those clients can be C clients or Java clients to server written in java.
Why I need to send over socket? Because there can be any process in any app on a same system who wants my app to capture there alarms and react accordingly.
Now, I can implement multiple Java clients who can connect to single Java server but how to do the same thing irrespective of it is Java client r C client.
If not socket programming, then what could be the other best way to make this communication happen
All low level network programming is written using sockets. you can have server written in any language communicate with client written in any language. To make this happen we have certain protocol which governs the communication like udp, tcp etc.
high level language provides api which will you to connect any server with single line of code without you needing to create socket. But in C you can create socket and connect it to the server. see this. All you need to know connect server and client is server ip and port...
While your requirements are very broad it looks a lot like a prime candidate for protocol buffers.
https://developers.google.com/protocol-buffers/
Language agnostic.
Platform neutral.
Fast.
Running on ZeroMQ (http://zeromq.org/) where you can push and pretty much run on top of everything.
I'm developing a Client application which talks to a Server using WebSockets. The Client is in C++ and the Server is in Java.
Can anyone suggest me any library which I can use on both Client side and Server side for communication using web sockets.
I never had experience with WebSocket, but try library cURL (libcurl). It was easiest for me to write clients for HTTP and FTP, using it. It have to help (but curl is useful just for clients, not for server).
If you are talking about sockets, normal sockets that connect on a port and wait for a connection on the server side and that connect to a given address on the client side, then I would recommend the boost asio socket on the c++ side and the standard java socket on the java side.
Just remind yourself of making sure that you transmit the datatype you expect.
Another cool implementation for both, java and c++, is ZeroMQ. I would recommend to take a look at it because it is easy to use and has implemented some really cool communication patterns.
I would like to have the clients query each other through the server without delay ( = no polling interval ).
Example: Server S, clients A and B
Client A wants to request Client B.
Client A will make a request to the server S, no problem there.
Then Server S needs to be able to request Client B but how to do that without polling?
All the node.js/APE (for PHP) technos are designed for the web, however I don't use a web server for that. Does Java has something close to a push technology/framework that is not web?
I would really prefer a solution that doesn't require each client to use their own reserved port (I don't want to end up with 1 WebService per client for example)
Note: all the clients are on the same machine.
A couple of options...
Plain socket communication. java.net.Socket, java.net.ServerSocket. Maximum flexibility but requires knowledge of low level TCP/IP API/concepts.
The good old RMI. Java based RPC layer on top of TCP/IP. Works good when client and server are both in Java and generally in same subnet. May give problems when client and/or server are natted.
Spring Remoting, it's actually pretty decent.
Bi-Directional Web Services. i.e. clients host their own WSes which the Server calls when it needs to do a callback.
JMS as someone already mentioned.
Distributed Data Structures, Check out http://www.hazelcast.com/
Lots of options to chose from, no need for webserver.
If you really don't want to use a web server then I would check out JMS. That being said, all the cool kids are using web servers these days since the protocols are so ubiquitous.
Your use case requires a messaging protocol. We don't really know the scope of your problem but you already said you want a server to exchange requests between clients, so I would go with an existing solution rather than a roll your own approach.
JMS has been mentioned and is certainly a viable Java based solution, another would be XMPP which is a real time communication protocol commonly used for instant messaging.
It is an open standard that has both server and client support in every major language and platform. This would allow you to have standalone apps, web based ones and apps for mobile devices all being able to communicate with each other. The only potential gotcha for your use case is that it is text based. Since you haven't said what requests you want to pass back and forth, I don't know if this will fit your bill or not.
You can use Smack for client side development in Java and any OS server you want.
I have not worked with HTTP post/get before, my up coming project in my office is based on http post/get in java. Its basically client - server based application. the client will post some info and I need to get that info and process the string and vice-verse. this project has to be developed on J2SE. You can assume this some thing like a JMS queue message processing stuff. I googled for the info but most of the information was for web application, mine should work like a message queue. Can someone explain me how to do this or point me where I can get some useful info.
Thanks
Arun
Well, if you don't need to specifically use strict HTTP, and you need to just use Java SE (and not Java EE, which rules out Servlets, JSPs, JMS, etc), then you need to probably investigate ServerSocket and Socket classes.
Server
Your server would need to listen on a TCP port (say, port 8080) - usually you would pick a port number between 1025 and 65,535, however if you are attempting to use an already defined service that has a default port, then use that. Note however, that on unix, in order to listen on any port below 1024, I believe you need to be root. Traditionally, port 80 is used for HTTP.
To listen on this port, you would need something like this in your code:
ServerSocket srvSocket = new ServerSocket(8080);
Socket socket = srvSocket.accept();
This pretty much the most basic code that would cause your application to wait until something connected to port 8080. Once connected, you could obtain both an InputStream and OutputStream for your connected client, by interrogating the returned socket object, allowing you to read content from the client, and inserting these requests in a queue. This queue could be then processed by some other Thread.
Client
In order for your client to connect to the server, you would need to use something based on the following example:
Socket connection = new Socket("server.domain.com", 8080);
OutputStream output = connection.getOutputStream();
You would then write your request to the server into the OutputStream (and read from the InputStream returned from getInputStream() if you expected a response)
The code supplied is pretty basic, but it should give you a rough idea of how to proceed. You can even use this method if you wanted to use real HTTP, however it might be a better idea to use some premade library if that was the case (although its probable that you're not going to require all functionality defined in the HTTP spec itself).
Anyway, I hope that provides you a good starting point from which to build.
Jetty is a popular web server, designed to easily be embedded in an application.
Its HTTP server component can run inside your application and respond to requests by dispatching to your custom code.
Jetty also features an HTTP client that you can use on the client side to send requests.
This is a rather big topic and I won't be able to post a complete guide, but Jetty's documentation is generally of very high quality and should be a good starting point.
I suggest you start with learning the basics of HTTP protocol. This article is a good starter. After you understood the basics follow the this article on how to programatically communicate (read/write) with HTTP servers. After that Google is your friend.
If you weren't restricted to J2SE, you could use Servlets for managing the POST/GET methods of HTTP. Evaluate if it is possible, otherwise you'd be reinventing the wheel
I also have a mainly SE background. On the client side, writing get/post is pretty easy. Or you can Google to find source code. I found that using REST was straightforward and understandable. On the server side, there are many options and I have very limited experience. I wrote the server using standard JEE6 and it wasn't too painful, but sounds like that is not an option for you.