Develop Reference

Can I add additional field (metadata) to thrift message?

I have generated client and server.
I need to add one more field to message in client and read it in server.
I think about to decorate TProtocol on client side and TProcessor on server side. E.g.:
// Client:
TTransport transport = new TSocket("localhost", 8888);
transport.open();
TProtocol protocol = new DecoratedProtocol(new TBinaryProtocol(transport));
// Server:
TServerTransport transport = new TServerSocket(8888);
TServer server = new TSimpleServer(new Args(transport).processor(new DecoratedProcessor(...)));
But I'm not sure what to do inside DecoratedProtocol and DecoratedProcessor?

There is a solution to add message meta data called the THeaderProtocol, but AFAIK right now this is only implemented for C++. That could be a starting point to implement the same for Java.
EDIT: I just noticed that fbthrift seems to implement THeaderProtocol for Java already.

Apache Thrift tutorial client stuck when using 2 clients - how to make the server multitask?

I'm executing Apache Thrift tutorial for Java.
When running 2 client processes at the same time, the server doesn't accept the 2nd client. Only after the first client finishes, the second one is accepted by the server.
Can anyone explain what's going on?
How can I make the server accept several connections in several threads?

Can anyone explain what's going on?
You already found it out: The TSimpleServer allows only for one connection at a time. It will be available again when the first client disconnects.
How can I make the server accept several connections in several threads?
Use one of the threading servers, whichever fits your use case best.
TThreadPoolServer
TThreadedSelectorServer
TNonBlockingServer
The half-sync/half-async server
Please note, that some of the servers require the client to use TFramedTransport.

Based on other answers, below is the code to enable executing multiple clients simultaneously.
Server (simple):
CalculatorHandler handler = new CalculatorHandler();
Calculator.Processor processor = new Calculator.Processor(handler);
TNonblockingServerSocket serverTransport = new TNonblockingServerSocket(9090);
THsHaServer.Args args = new THsHaServer.Args(serverTransport);
args.processor(processor);
args.transportFactory(new TFramedTransport.Factory());
TServer server = new THsHaServer(args);
server.serve();
Client:
transport = new TSocket("localhost", 9090);
transport.open();
TProtocol protocol = new TBinaryProtocol(new TFramedTransport(transport));
Calculator.Client client = new Calculator.Client(protocol);
perform(client);

Multi-threaded connection manager with Jersey Apache Client 4

I have a Jersey client up and running, using the Apache Client 4 library, like this:
private Client createClient() {
ApacheHttpClient4Config cc = new DefaultApacheHttpClient4Config();
// boring stuff here
return ApacheHttpClient4.create(cc);
}
But this by default uses a BasicClientConnManager, which doesn't allow multi-threaded connections.
The ApacheHttpClient4Config Javadoc says that I need to set the PROPERTY_CONNECTION_MANAGER to a ThreadSafeClientConnManager instance if I want multi-threaded operation. I can do this, and it works OK:
private Client createClient() {
ApacheHttpClient4Config cc = new DefaultApacheHttpClient4Config();
cc.getProperties().put(ApacheHttpClient4Config.PROPERTY_CONNECTION_MANAGER,
new ThreadSafeClientConnManager());
// boring stuff here
return ApacheHttpClient4.create(cc);
}
But ThreadSafeClientConnManager is deprecated. This is annoying.
The more modern version is PoolingHttpClientConnectionManager. Unfortunately, though, the ApacheHttpClient4.create() method requires the connection manager to be an implementation of ClientConnectionManager (itself deprecated), and PoolingHttpClientConnectionManager doesn't implement that interface. So if I try to use it, my connection manager gets ignored and we're back to a BasicClientConnManager.
How can I end up with a thread-safe client without using anything that's deprecated?

You can create the client as follows (see https://github.com/phillbarber/connection-leak-test/blob/master/src/test/java/com/github/phillbarber/connectionleak/IntegrationTestThatExaminesConnectionPoolBeforeAndAfterRun.java#L30-L33):
client = new ApacheHttpClient4(new ApacheHttpClient4Handler(HttpClients.custom()
.setConnectionManager(new PoolingHttpClientConnectionManager())
.build(), null, false));

Jetty Websocket: can't find SimpleEchoSocket

Following Jetty documentation and answer to this question creation of websocket client is as simple as
WebSocketClient client = new WebSocketClient();
SimpleEchoSocket socket = new SimpleEchoSocket();
try {
client.start();
URI echoUri = new URI(destUri);
ClientUpgradeRequest request = new ClientUpgradeRequest();
client.connect(socket, echoUri, request);
System.out.printf("Connecting to : %s%n", echoUri);
socket.awaitClose(5, TimeUnit.SECONDS);
}
But I can't find SimpleEchoSocket! I try several versions of org.eclipse.jetty.websocket:websocket-client but had no success. Looks like documentation is outdated, but maybe I am doing something wrong? How can I use this example from Jetty doc?

SimpleEchoSocket is your socket implementation.
In other words, its your code, your class.
Something that implements the on open, on close, on message logic in the ways that the same documentation explains.
You have a few choices here, it can be jetty api specific, or jsr-356 (aka javax.websocket) specific.
Then you choose between a traditional class that implements an interface, or one that is marked up with annotations.

Traditional IO in client side and NIO in Server, how do i get specific msg if client sends multiple message in the same socket?

I am using Apache Mina in the Server side. I've a client which is written in tradition IO. Here's the CLIENT side code that sends data to server.
class SomeClass extends Thread
{
Socket socket;
//Constructor
SomeClass()
{
Socket socket = ...
}
public void run()
{
while (j++ < 10)
{
System.out.println("CLIENT[" + clientNo + "] Send Message =>" + requests[clientNo][j]);
OutputStream oStrm = socket.getOutputStream();
byte[] byteSendBuffer = (requests[clientNo][j]).getBytes();
oStrm.write(byteSendBuffer);
oStrm.flush();
}
}
}
The above thread is run for say 20 times. So 20 sockets are created. And in 1 socket, many messages are send. With a server written using IO socket classes i'm able to retrieve data perfectly.
THe problem comes in the Apache Mina based Server which uses BUFFER! I am not able to get individual messages.
How do i get individual messages (given i'm not able to change anything in client, AND the length of individual messages are not known)
Server Side Code
Socket Creation
public static void main(String[] args) throws IOException, SQLException {
System.out.println(Charset.defaultCharset().name());
IoAcceptor acceptor = new NioSocketAcceptor();
ProtocolCodecFilter(charset.newEncoder(),charset.newDecoder() ));
acceptor.setHandler( new TimeServerHandler() );
acceptor.getSessionConfig().setReadBufferSize(64 );
acceptor.getSessionConfig().setIdleTime( IdleStatus.BOTH_IDLE, 10 );
acceptor.bind( new InetSocketAddress(PORT) );
}
Handler Code
public void messageReceived(IoSession session, Object message) throws Exception {
AbstractIoBuffer bf = (AbstractIoBuffer)message;
Charset charset = Charset.forName("UTF-8");
CharsetDecoder decoder = charset.newDecoder();
String outString = bf.getString(decoder);
}

How do i get individual messages
You don't. There is no such thing as a message in TCP. It is a byte-stream protocol. There are no message boundaries and there is no guarantee that one read equals one write at the other end.
(given i'm not able to change anything in client, AND the length of individual messages are not known)
Your are going to have to parse the messages to find where they stop according to the definition of the application protocol. If that isn't possible because, say, the protocol is ambiguous, the client will have to be junked. However it seems that as you can't change the client, it must already work with an existing system, so the guy before you had the same problem and solved it somehow.

MINA is actually a very elaborate framework to solve your problem in an elegant way. Its basic concept is a filter chain, in which a series of filters are applied on an incoming message.
You should implement a protocol decoder (implementing MessageDecoder) and register it in your MINA filter chain. That decoder should parse byte buffers to the object representation of your choice.
Then, you can register a message handler that handles complete messages.