monq.net

Class TcpServer

java.lang.Object

monq.net.TcpServer

All Implemented Interfaces:

java.lang.Runnable

public class TcpServer
extends java.lang.Object
implements java.lang.Runnable

a simple socket server able to serve multiple client connections in parallel. Using this class make sense, if the service to be provided can be coded as a transformation of data read from an java.io.InputStream and then written to a java.io.OutputStream. To be able to serve several clients in parallel, a new service object is needed for every connection. Therefore the constructor has a ServiceFactory as a parameter rather than a service object.

A typical use of this class involves the following steps:

1. Write a class implementing java.lang.Runnable. Its run() method should read input from an InputStream, transform it and write the result to an OutputStream.
2. Write a class implementing a ServiceFactory to return instances of the above class.
3. Create a TcpServer with the factory.
4. Call the serve() method of the TcpServer.

If you stick your ServiceFactory into a FilterServiceFactory between steps 2 and 3 and pass the result to the TcpServer, you get a pipe filter which can be used in conjunction with other pipe filters and with DistPipeFilter to built a distributed pipe on the network.

As soon as clients contact the server, it will call the factory method to fetch a new service instance. It connects it to the input and output stream from the client, wraps it up in a Thread and starts it. By default 10 such service threads can be running in parallel. When a thread finishes, TcpServer takes care to close the streams.

Author:

© 2004 Harald Kirsch

Constructor Summary

Constructors

Constructor and Description
TcpServer(int port, ServiceFactory fac) creates a server to listen on the given port.
TcpServer(int port, ServiceFactory fac, int slots)
TcpServer(java.net.ServerSocket s, ServiceFactory fac, int slots) creates a server to listen on the given socket.

Method Summary

Modifier and Type	Method and Description
void	run() calls serve() and catches exceptions to write them to the log.
void	serve() starts the server, waiting for connections and serving up to n requests in parallel.
TcpServer	setDebug() given that logging was enabled with setLogging(), we now switch to really verbose logging.
TcpServer	setLogging(java.io.PrintStream log)
void	shutdown() closes the socket on which the server is accepting connections with the effect, that serve() immediately returns.
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

TcpServer

public TcpServer(java.net.ServerSocket s,
                 ServiceFactory fac,
                 int slots)

creates a server to listen on the given socket. Connection request are honoured with whatever service the given ServiceFactory delivers. Up to slots services are run in parallel. If all slots are filled, incoming requests are put on hold by the underlying tcp machinery.

Important: The services created by fac should not close the input and output stream passed to them. If they close one of them, this immediately closes the socket and thereby the other one too. Both streams are close by the server itself after the service thread finishes.

TcpServer

public TcpServer(int port,
                 ServiceFactory fac)
          throws java.io.IOException

creates a server to listen on the given port. Up to 10 connections are serviced in parallel.

Throws:

java.io.IOException - if no server socket can be opened for the given port.

TcpServer

public TcpServer(int port,
                 ServiceFactory fac,
                 int slots)
          throws java.io.IOException

Throws:

java.io.IOException

Method Detail

setLogging

public TcpServer setLogging(java.io.PrintStream log)

Returns:

this

setDebug

public TcpServer setDebug()

given that logging was enabled with setLogging(), we now switch to really verbose logging.

Returns:

this

run

public void run()

calls serve() and catches exceptions to write them to the log. This method is only here so that a TcpServer itself can be put into a Thread. If the server activity is anyway the main operation of your program, just call serve().

Specified by:

run in interface java.lang.Runnable

shutdown

public void shutdown()

closes the socket on which the server is accepting connections with the effect, that serve() immediately returns. Any currently running service threads are not affected.

serve

public void serve()
           throws java.io.IOException

starts the server, waiting for connections and serving up to n requests in parallel. The value n is the number of slots defined in the constructor. This method only returns if the current thread's interrupt() method is called. Note, however, that services not yet finished are just left running. They are not forcibly shut down.

Throws:

java.io.IOException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object