Re: Class.getMethod in class's static initializer block

From:
Mark Space <markspace@sbc.global.net>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 01 Aug 2007 21:44:39 GMT
Message-ID:
<b97si.54599$5j1.25437@newssvr21.news.prodigy.net>
chucky wrote:

Method m = map.get(str);
if(m != null)
    m.invoke();
else{ /* default code */ }


You seem to have got the info you needed already. I just wanted to add
that I had some similar code for a "command line server" project. You
might find some good ideas in the code below, or I might get criticized
for language abuse. Either way it'll be educational for someone. ^_^

/*
  * ServerTest.java
  *
  * Created on July 13, 2007, 4:28 PM
  *
  * To change this template, choose Tools | Template Manager
  * and open the template in the editor.
  */

package servertest;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.ConsoleHandler;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
  *
  * @author B
  */

/**
  * Copyright 2007 All rights reserved.
  */

public class ServerTest implements Runnable
{
     static private final boolean DEBUG = true;

     public static void main(String[] args)
     {
         // TODO code application logic here
         new Thread( new ServerTest() ).start();
     }

     // DEFAULT CONSTRUCTOR
     /** Creates a new instance of ServerTest */
     public ServerTest()
     {
         if( logger == null )
         {
             logger = Logger.getLogger( ServerTest.class.getName() );
             if( DEBUG )
             {
                 ConsoleHandler ch = new ConsoleHandler();
                 ch.setLevel( Level.ALL );
                 logger.addHandler( ch );
                 logger.setLevel( Level.ALL );
                 logger.setUseParentHandlers( false );
             }
         }
// port = 25; // 25 is telnet port #
         port = 4040;
         runServer = true;
         commandList = new HashMap<String, CommandLine>();
         addCommand( new QuitLineCommand() );
         addCommand( new HelloLineCommand() );
         addCommand( new ErrorLineCommand() );
         addCommand( new TestLineCommand( "test", new CommandRunner()
         { public ReturnCode runCommand( String s )
           { return (ReturnCode) new TestReturnCode( 0, false, "Test
succeded." ); }} ));
     }

     public void addCommand( CommandLine cl )
     {
         commandList.put( cl.getCommand(), cl );
     }

     public void run()
     {
         while( runServer )
         {
             try
             {
                 ServerSocket sock = new ServerSocket( port );
                 logger.info( "Accepting connections on port " + port );
// System.err.println( "Accepting connections on port " +
port );

                 Socket client = sock.accept();

                 InputStream clientInput = client.getInputStream();
                 OutputStream clientOutput = client.getOutputStream();

                 PrintWriter clientPW = new PrintWriter( clientOutput,
true );
                 BufferedReader clientBR = new BufferedReader( new
InputStreamReader( clientInput ) );

                 while( true )
                 {
                     String line = clientBR.readLine();
// System.err.println( line );
                     logger.finer( line );
                     if( line.length() == 0 )
                     {
                         continue;
                     }
                     String commands [] = line.split( ":", 2 );
// System.err.print( commands.length + " commands " );
                     logger.log( Level.FINEST, "Split commands are ",
commands );
// for( int i = 0; i < commands.length; i++ )
// {
// System.err.print( commands[i] + ", " );
// }
// System.err.println();

                     CommandLine exeObj = null;
                     if( commands.length >= 1 )
                     {
                         exeObj = commandList.get( commands[0] );
                     }
                     if( exeObj != null )
                     {
// System.err.println( exeObj );
                         String arguments = null;
                         if( commands.length > 1 )
                         {
                             arguments = commands[1];
                         }
                         ReturnCode rc = exeObj.runCommand( commands[0],
arguments );
                         if( rc == null )
                         {
// System.err.println( "return object was
null!" );
                             logger.warning( "Return object was null!" );
                             continue;
                         }
                         if( rc.isError() )
                         {
                             clientPW.print( '\07' ); // ASCII bell
                         }
                         if( rc.getCode() != 0 )
                         {
                             clientPW.print( "(" + rc.getCode() +")" );

                         }
                         if( rc.getMessage() != null )
                         {
                             clientPW.print( rc.getMessage() );
                         }
                         clientPW.println();
                         if( rc.getCode() == -1 )
                         {
                             runServer = false;
                             break;
                         }
                     }
                     else
                     {
                         clientPW.println( "\07Command not found." );
      // \07 is ASCII bell
// clientPW.flush();
                     }
                 }

             }
             catch (IOException ex)
             {
                 ex.printStackTrace();
             }

         }

     }

     private int port;
     private boolean runServer;
     private Map<String, CommandLine> commandList;
     private static Logger logger;
}

class LineParser
{
     public boolean addCommand( CommandLine c )
     {
         //...
         return true;
     }

     public ReturnCode parseLine( String line )
     {
         ReturnCode rc = null;
         //...
         return rc;
     }
}

interface CommandLine
{
// public CommandLine( String command );
     public String getCommand();
     public ReturnCode runCommand( String command, String args );
}

interface CommandRunner
{
     public ReturnCode runCommand( String args );
}

class TestLineCommand implements CommandLine
{
     public TestLineCommand( String command, CommandRunner exec )
     {
         this.command = command;
         this.exec = exec;
     }

     public String getCommand()
     {
         return command;
     }

     public ReturnCode runCommand(String command, String args)
     {
         return exec.runCommand( args );
     }

     private String command;
     private CommandRunner exec;
}
class QuitLineCommand implements CommandLine
{
     public String getCommand()
     {
         return "quit";
     }

     public ReturnCode runCommand(String command, String args)
     {
         return (ReturnCode) new TestReturnCode( -1, false, "Good-bye" );
     }
}

class ErrorLineCommand implements CommandLine
{
     public String getCommand()
     {
         return "error";
     }

     public ReturnCode runCommand(String command, String args)
     {
         return (ReturnCode) new TestReturnCode( 1, true, args );
     }

}

class HelloLineCommand implements CommandLine
{
     public String getCommand()
     {
         return "hello";
     }

     public ReturnCode runCommand( String command, String args )
     {
         return (ReturnCode) new TestReturnCode( 0, false, "Hello World!
  You typed: " + args );
     }
}

interface ReturnCode
{
     public int getCode();
     public boolean isError();
     public String getMessage();
// public String getExtendedMesage();
}

class TestReturnCode implements ReturnCode
{
     public TestReturnCode( int code, boolean isError, String message )
     {
         this.code = code;
         this.error = isError;
         this.message = message;
     }

     public int getCode()
     {
         return code;
     }

     public boolean isError()
     {
         return error;
     }

     public String getMessage()
     {
         return message;
     }

     private int code;
     private boolean error;
     private String message;
}

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