// Copyright MageLang Institute; Version $Id: //depot/main/src/edu/modules/RMI2/magercises/BootstrapHTTPServer/working/ClassFileServer.java#2 $

/*
 * Copyright (c) 1996, 1996, 1997 Sun Microsystems, Inc. All Rights Reserved.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 */
//package examples.classServer;

import java.io.*;
import java.net.*;

/**
 * The ClassFileServer implements a ClassServer that
 * reads class files from the file system. See the
 * doc for the "Main" method for how to run this
 * server.
 */
public class ClassFileServer

extends ClassServer
{
    private String classpath;

    private static int DefaultServerPort = 2001;

    /**
     * Constructs a ClassFileServer.
     *
     * @param classpath the classpath where the server locates classes
     */
    public ClassFileServer(int port, String classpath) throws IOException
    {
        super(port);
        this.classpath = classpath;
    }

    /**
     * Returns an array of bytes containing the bytecodes for
     * the class represented by the argument <b>path</b>.
     * The <b>path</b> is a dot separated class name with
     * the ".class" extension removed.
     *
     * @return the bytecodes for the class
     * @exception ClassNotFoundException if the class corresponding
     * to <b>path</b> could not be loaded.
     */
    public byte[] getBytes(String path)  throws IOException, ClassNotFoundException
    {
        System.out.println("reading: " + path);
        File f = new File(classpath + File.separator +  path.replace('.', File.separatorChar) + ".class");
        int length = (int)(f.length());

        if (length == 0)
        {
            System.out.println( "Zero length file" );
            throw new IOException("File length is zero: " + path);
        }
        else
        {
            FileInputStream fin = new FileInputStream(f);
            DataInputStream in = new DataInputStream(fin);

            byte[] bytecodes = new byte[length];
            in.readFully(bytecodes);
            return bytecodes;
        }
    }

    /**
     * Main method to create the class server that reads
     * class files. This takes two command line arguments, the
     * port on which the server accepts requests and the
     * root of the classpath. To start up the server: <br><br>
     *
     * <code>   java ClassFileServer <port> <classpath>
     * </code><br><br>
     *
     * The codebase of an RMI server using this webserver would
     * simply contain a URL with the host and port of the web
     * server (if the webserver's classpath is the same as
     * the RMI server's classpath): <br><br>
     *
     * <code>   java -Djava.rmi.server.codebase=http://zaphod:2001/ RMIServer
     * </code> <br><br>
     *
     * You can create your own class server inside your RMI server
     * application instead of running one separately. In your server
     * main simply create a ClassFileServer: <br><br>
     *
     * <code>   new ClassFileServer(port, classpath);
     * </code>
     */
    public static void main(String args[])
    {
        int port = DefaultServerPort;
        String classpath = "";

        if (args.length >= 1)
        {
            port = Integer.parseInt(args[0]);
        }

        if (args.length >= 2)
        {
            classpath = args[1];
        }

        try
        {
            new ClassFileServer(port, classpath);
            System.out.println("ClassFileServer started...");
        }
        catch (IOException e)
        {
            System.out.println("Unable to start ClassServer: " + e.getMessage());
            e.printStackTrace();
        }
    }
}