/**
	An example illustrating the implementation of a <I>server</I> in the
	<A HREF="http://www.speech.kth.se/proj/broker/>Broker architecture</A>.
	
	This server implements one function: add with a variable number of 
	integer arguments.
	*/

import SE.kth.speech.broker.*;
import java.util.StringTokenizer;
import java.util.Vector;
import java.net.UnknownHostException;
import java.io.IOException;


public class Adder implements ServiceProvider
{
	// This is a stand-alone Java program
	// It takes as arguments the host and port that the broker is running on.
	// it never terminates.
	public static void main( String[] args )
	{
		if( args.length != 2 )
			System.err.println("Two arguments: <brokerHost> <brokerPort>");
		else
			try	
			{	
				new Adder( args[0], Integer.parseInt( args[1] ) ); 
			}
		  catch( UnknownHostException exception )
			{ 
				System.err.println("The broker host is unknown ('" + 
													 exception.getMessage() + "'");
				System.exit(-1);
			}
			catch( ServerDownException e )
			{
				System.err.println("Either the network is down, or there is no " +
													 "broker running on the specified host and port" );
				System.exit(-1);
			}
			catch( IOException e )
			{
				System.err.println("An I/O error occurred: " + e.getMessage() );
				System.exit(-1);
				
			}
			
		// The Adder will create a BrokerClient with a thread of its own, therefore
		// the Java program will not terminate after the new Adder
	}
	
	private Adder( String host, int port ) 
		throws UnknownHostException, ServerDownException, IOException
	{
		BrokerClient brokerClient;
		
		brokerClient = new BrokerClient( "Adder", host, port, this, true );
		brokerClient.connect();
	}
	
	// implementation of the ServiceProvider interface
	public Object brokerCall( BrokerClient brokerClient, String data ) throws BrokerException
	{
		StringTokenizer tokenizer;
		String method;
		int sum = 0;
		String numberName = null;
		
		tokenizer = new StringTokenizer( data );
		
		if( !tokenizer.hasMoreTokens() )
			throw new BrokerException( "No method specified" );
		
		method = tokenizer.nextToken();
		if( !method.equalsIgnoreCase( "add" ) )
			throw new BrokerException( "Function '" + method + "' not supported." );
		
		// now read the numbers
		try
		{
			while( tokenizer.hasMoreTokens() )
			{
				int number;
				
				numberName = tokenizer.nextToken();
				
				number = Integer.parseInt( numberName );
				sum += number;
			}
		}
		catch( NumberFormatException e )
		{ 
			// error message with empathy are strongly supported by the Broker 
			// architecture
			throw new BrokerException( "The Adder deeply regrets that '" + 
																 numberName + "' is not a number." );
		}
		
		// this method must return either a String or a Vector of Strings
		return String.valueOf( sum );
	}
	
	public Object brokerCall( BrokerClient brokerClient, Vector data ) throws BrokerException 
	{
		throw new BrokerException( "This server doesn't support multiline calls");
	}
}