Client Server

importjava.net.ServerSocket;
/**
 * -- Main Server Class; Listening on a port for client; If there is a client,
 * starts a new Thread and goes back to listening for further clients. --
 */
publicclass ComServer
{
staticbooleanGL_listening=true;
/**
 * -- Main program to start the Server --
 */
publicstaticvoidmain(String[]args)throwsIOException
{
ComServersrv=newComServer();
srv.listen();
}// --- End of Main Method ---
/**
 * -- Server method; Listen for client --
 */
publicintlisten()throwsIOException
{
ServerSocketserverSocket=null;
intiPortNumber=9090;
// --- Open the Server Socket where this should listen ---
try{
System.out.println("*** Open the listening socket; at:"+iPortNumber+" ***");
serverSocket=newServerSocket(iPortNumber);
}catch(IOExceptione){
System.err.println("Could not listen on port:"+iPortNumber);
System.exit(1);
}
while(GL_listening)
{
ComServerThreadclientServ;
// --- Listening for client; If there is a client start a Thread -
System.out.println("*** Listen for a Client; at:"+iPortNumber+" ***");
clientServ=newComServerThread(serverSocket.accept());
// --- Service a Client ---
System.out.println("*** A Client came; Service it ***");
clientServ.start();/* --- Use for multy Threaded --- */
// clientServ.run(); /* --- Use for Single Threaded --- */
}
// --- Close the Server socket; Server exiting ---
serverSocket.close();
return0;
}// --- End of listen Method --- 
}// --- End of ComServer Class ---

/**
 * -- A class extended from a Thread; Responsible to service one client --
 */
class '''ComServerThread'''extendsThread
{
privateSocketclientSocket=null;
COM_DATAtDataFromClient;
COM_DATAtDataToClient;
ObjectInputStreamoIn;
ObjectOutputStreamoOut;
/**
 * -- Constructor --
 */
publicComServerThread(Socketsocket)
{
super("ComServerThread");
this.clientSocket=socket;
}// -- End of ComServerThread() constructor --
/**
 * -- Overrun from the Thread (super) class --
 */
publicvoidrun()
{
try{
// --- Create the Writer; will be used to send data to client ---
oOut=newObjectOutputStream(clientSocket.getOutputStream());
// --- Create the Reader; will be used to get data from client ---
oIn=newObjectInputStream(clientSocket.getInputStream());
// --- Create a new protocol object ---
ComProtocolcomp=newComProtocol();
// --- Send something to client to indicate that server is ready ---
tDataToClient='''comp.processInput(null);'''
'''sendDataToClient'''(tDataToClient,oOut);
// --- Get the data from the client ---
while(true)
{
try{
tDataFromClient='''getDataFromClient(oIn)''';
// --- Parse the request and get the reply ---
tDataToClient='''comp.processInput(tDataFromClient);'''
// --- Send data to the Client ---
'''sendDataToClient'''(tDataToClient,oOut);
}
catch(EOFExceptione){
System.out.println("Client Disconnected, Bye, Bye");
break;
}
// --- See if the Client wanted to terminate the connection ---
if(tDataToClient.bExit)
{
System.out.println("Client said Bye. Bye");
break;
}
}
// --- Close resources; This client is gone ---
comp.Final();
oOut.close();
oIn.close();
clientSocket.close();
}catch(IOExceptione){
e.printStackTrace();
}
}// -- End of run() Method --
/**
 * Get data from Client 
 */
privatestaticCOM_DATA'''getDataFromClient'''(ObjectInputStreamoIn)throwsIOException
{
COM_DATAtDataFromClient=null;
// --- Initialize variables ---
// tDataFromClient = new COM_DATA();
while(tDataFromClient==null)
{
try{
// --- Read Line Number first --
tDataFromClient=(COM_DATA)oIn.readObject();
}catch(ClassNotFoundExceptione){
System.out.println("ClassNotFound");
}
}
System.out.println("Get: "+tDataFromClient.comData);
returntDataFromClient;
}// --- getDataFromClient() Method --- 
/**
 * Send data to Client 
 */
privatestaticvoid'''sendDataToClient'''(COM_DATAtDataToClient,
ObjectOutputStreamoOut)throwsIOException
{
System.out.println("Sent: "+tDataToClient.comData);
oOut.writeObject(tDataToClient);
return;
}// -- End of sendDataToClient() Method --
}// --- End of ComServerThread class ---

class '''ComProtocol'''
{
privatestaticfinalintCOM_STATUS_WAITING=0;
privatestaticfinalintCOM_STATUS_READY_SENT=1;
privatestaticfinalintCOM_STATUS_DATA_SENT=2;
privatestaticfinalintCOM_STATUS_WAITING_FOR_TERMINALID=3;
privateintstate=COM_STATUS_WAITING;

// --- Reference to 'BACK-END' module --- 
privateMqTeAccessmqTe;
...
/**
 * Create a protokol object; CAll MQ INI function
 */
publicComProtocol()
{
intiRet=0;
// --- Initialize 'BACK-END' modules ---
mqTe....
...
}
/**
 * --- Process the Input and Create the output to the Client ---
 */
publicCOM_DATAprocessInput(COM_DATAtheInput)
{
COM_DATAtheOutput;
// --- Initialize Variables ---
theOutput=newCOM_DATA();
// --- Check if the Clients want to disconnect ---
if(theInput!=null)
{
if(theInput.comData.equals('''"!BYE.@"'''))
{
// --- The Client wants to terminate; Echo data back to client
theOutput.comData="BYE.";
// --- Mark the communication to be terminated ---
theOutput.bExit=true;
// --- Set the internal state to wait for a new client ---
state=COM_STATUS_WAITING;
// --- Return Data object to be sent to the client ---
returntheOutput;
}
if(theInput.comData.equals('''"!SHUTDOWN.@"'''))
{
// --- The Client wants to terminate; Echo data back to client
theOutput.comData="BYE.";
// --- Mark the communication to be terminated ---
theOutput.bExit=true;
// --- Tell the server to stop listening for new clients ---
ComServer.GL_listening=false;
// --- Set the internal state to wait for a new client ---
state=COM_STATUS_WAITING;
// --- Return Data object to be sent to the client ---
returntheOutput;
}
}
if(state==COM_STATUS_WAITING)
{
// --- Send ready Message to the Client ---
theOutput.comData="Ready:";
// --- Set the internal state ready; and wait for TerminalId ---
state=COM_STATUS_WAITING_FOR_TERMINALID;
}
elseif(state==COM_STATUS_WAITING_FOR_TERMINALID)
{
intiRet;
// --- Get the Terminal ID ---
sTermId=theInput.comData;
// --- Call 'BACK-END' modules ... ---
mqTe....
...
// --- Send ready Message with the Server Version to the Client ---
theOutput.comData="Ready;Server Version 1.0:";
// --- Set the internal state raedy; and wait for TerminalId ---
state=COM_STATUS_READY_SENT;
}
elseif(state==COM_STATUS_READY_SENT)
{
intiRet;
StringsCommand=theInput.comData;
// --- Call 'BACK-END' modules ...
...
/*
 ** --- Check if we should get Response data ---
 */
if(theInput.iRet==COM_DATA.NOWAIT_FOR_RESPONSE){
// -- Set the Output Value ---
theOutput.iRet=iRet;
theOutput.comData="";
}
else{
// --- Call 'BACK-END' modules ---
mqTe....
// --- Set the Output Value ---
theOutput.comData=mqTe.sResponseBuffer;
theOutput.iRet=iRet;
}
}
returntheOutput;
}// --- End of Method processInput() ---
}// --- End of ComProtocol Class Definition ---
----

/**
 * COM_DATA data structure 
 */
publicclass COM_DATAimplementsSerializable
{
publicStringcomData;
publicbooleanbExit;
publicintiRet;
/**
 * --- Constants values can be passed in in iRet to the Server ---
 */
staticfinalintWAIT_FOR_RESPONSE=0;
staticfinalintNOWAIT_FOR_RESPONSE=1;
/**
 * Initialize the data structure
 */
publicCOM_DATA()
{
comData="";
bExit=false;
iRet=0;
}// -- End of COM_DATA() Constructor -- 
/**
 * Copy over it contents 
 */
publicvoidcopy(COM_DATAtSrc)
{
this.comData=tSrc.comData;
this.bExit=tSrc.bExit;
this.iRet=tSrc.iRet;
return;
}
}// -- End of COM_DATA class --

publicclass ComClient
{
privateSocketcomSocket;
privateObjectOutputStreamoOut;
privateObjectInputStreamoIn;
privatebooleanIsItOpen=false;
/**
 * --- Open Socket ---
 */
publicvoidopenCom(StringsServerName,
intiPortNumber)throwsUnknownHostException,
IOException
{
try{
// --- Open Socket for communication ---
comSocket=newSocket(sServerName,iPortNumber);
// --- Get Stream to write request to the Server ---
oOut=newObjectOutputStream(comSocket.getOutputStream());
// --- Get Stream// to read from the Server
oIn=newObjectInputStream(comSocket.getInputStream());
// --- Set internal Member variable that the Communication opened ---
IsItOpen=true;
}catch(java.net.UnknownHostExceptione){
System.err.println("(openCom:)Don't know about host: "+sServerName);
IsItOpen=false;
throw(e);
}catch(java.io.IOExceptione){
System.err.println("(openCom:)Couldn't get I/O for the connection to: "+sServerName);
IsItOpen=false;
throw(e);
}
}
/**
 * --- Check if Socket is open ---
 */
publicbooleanisItOpen()
{
returnIsItOpen;
}
/**
 * --- Get data string from the Server ---
 */
publicvoidgetServerData(COM_DATAtServData)throwsIOException
{
// --- Initialize Variables ---
tServData.comData="";
// --- Get the Response from the Server --- 
try{
tServData.copy((COM_DATA)oIn.readObject());
}
catch(ClassNotFoundExceptione){
System.out.println("Class Not Found");
}
System.out.println("Server: "+tServData.comData);
if(tServData.comData.equals("BYE."))
{
tServData.bExit=true;
}
return;
}
/**
 * --- Send data to the Server ---
 */
publicvoidsendDataToServer(COM_DATAtServData)throwsIOException
{
// --- Send the data string ---
System.out.println("Send: "+tServData.comData);
oOut.writeObject(tServData);
return;
}
/**
 * --- Close Socket --- 
 */
publicvoidcloseCom()throwsIOException
{
oOut.close();
oIn.close();
comSocket.close();
IsItOpen=false;
}
}