How do
i create a stream based Server Service
Firstly, in the same way that publish / subscribe and
message queues use an RNAME,
the p2p api also requires one to connect to the realm.
The code snippet below shows you how this is achieved
:
String[] RNAME=({“nsp://127.0.0.1:9000”});
nSessionAttributes nsa=new nSessionAttributes(RNAME);
nServiceFactory factory = new nServiceFactory( nsa
);
Once the service factory is created, and we are connected
to the realm, we can create the stream server service.
nServerService server = factory.createStreamService(
"example",
"this service is an example" );
while ( true ) {
nStreamService serv = (nStreamService)server.accept();
/**
.your logic goes here....i.e. what does you server
service do with the instance of nStreamService created
once a connection is established?
does it go and query a database, make a connection
send an email? etc etc.
*/
System.out.println("Got connection "+serv.getServiceInfo().getName());
}
When connections are made to the stream service, the
service instance created by the server service contains
both and input and an output stream, which can be written
to and read from.
The input stream represents data coming from the client
service, the output stream represents data going to
the client service. To obtain the input stream of the
server service instance, use the following:
InputStream is = serv.getInputStream();
To obtain the output stream of the server service instance,
use the following:
OutputStream os = serv.getOutputStream();
How do i
create a stream based Client Service
The nServiceFactory object establishes a connection
with the nirvana realm, and is the factory object from
which we can then find our service, or obtain a list
of available services:
nServiceInfo info = factory.findService("example");
nStreamService serv = (nStreamService)factory.connectToService(
info );
Once you have connected to the service, and you have
an instance of the service, you can then begin writing
data to the stream service. To do this you must first
obtain the output stream of the service by using the
following command:
OutputStream os = serv.getOutputStream();
And then write the data you wish to write to the output
stream:
os.write("Hello".getBytes());
os.flush();
To receive responses from the server service, the client
service needs to read from the input stream of the stream
service. To do this you must first obtain the reference
to the input stream:
InputStream is = serv.getInputStream();
And then read from the stream:
byte[] buff = new byte[ 100 ];
try {
InputStream is = serv.getInputStream();
while ( true ) {
is.read( buff );
System.out.println("Read "+new String(buff));
}
}
catch ( Exception ex ) {
}
For more information on Nirvana p2p, please see the
API documentation.
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