PC World Komputer 1995 November/PCWK1195.iso/inne/win95/sieciowe/hotja32.lzh/hotjava/classsrc/net/www/httpd/chatroom.java

Text File | 1995-08-11 | 4KB | 175 lines

/*
 * @(#)ChatRoom.java    1.1 95/04/03
 *
 * Copyright (c) 1995 Sun Microsystems, Inc.  All Rights reserved
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file copyright.html
 * for further important copyright and licensing information.
 *
 * 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 net.www.httpd;

import java.io.*;
import java.util.*;
import net.NetworkServer;

/**
 * A class to implement a room in which people can chat.
 * @author  James Gosling
 */


class ChatRoom {
    static final int histlen = 20;
    String history[] = new String[histlen];
    int histpos = 0;
    String name;
    PrintStream clients[] = new PrintStream[1];
    String clnames[] = new String[1];

    private ChatRoom (String n) {
    name = n;
    }

    static Hashtable ht = new Hashtable(20);
    static ChatRoom New(String n) {
    Object o = ht.get(n);
    if (o != null)
        return (ChatRoom) o;
    ChatRoom ret = new ChatRoom (n);
    ht.put(n, ret);
    return ret;
    }

    synchronized void addListener(PrintStream p, String clname) {
    int i;
    for (i = clients.length; --i >= 0 && clients[i] != null;);
    addString(clname + " has just entered the room.\n");
    if (i >= 0) {
        clients[i] = p;
        clnames[i] = clname;
    } else {
        PrintStream nc[] = new PrintStream[clients.length * 2];
        System.arraycopy(clients, 0, nc, 0, clients.length);
        String nn[] = new String[nc.length];
        System.arraycopy(clnames, 0, nn, 0, clnames.length);
        nc[clients.length] = p;
        nn[clients.length] = clname;
        clients = nc;
        clnames = nn;
    }
    p.print("Welcome to " + name + "\n");
    int nseen = 0;
    String lastName = null;
    for (i = clients.length; --i >= 0;)
        if (clients[i] != null && clients[i] != p) {
        String n = clnames[i];
        if (lastName != null) {
            if (nseen > 1)
            p.print(", ");
            p.print(lastName);
        }
        lastName = n;
        nseen++;
        }
    if (lastName != null) {
        if (nseen > 1)
        p.print(" and ");
        p.print(lastName);
        p.print(nseen > 1 ? " are " : " is ");
        p.print("already in the room.\n");
    } else
        p.print("You are alone in the room.\n");
    for (i = history.length; --i >= 0;) {
        int slot = histpos - i;
        if (slot < 0)
        slot += history.length;
        if (history[slot] != null) {
        p.print(history[slot]);
        p.print("\n");
        }
    }
    p.flush();
    }

    synchronized void removeListener(PrintStream p) {
    int i;
    int nlisteners = 0;
    for (i = clients.length; --i >= 0;)
        if (clients[i] == p) {
        try {
            clients[i].close();
        } catch(Exception e);
        clients[i] = null;
        addString(clnames[i] + " has left the room.\n");
        } else if (clients[i] != null)
        nlisteners++;
    if (nlisteners == 0) {
        ht.remove(name);
    }
    }

    synchronized void addString(String s) {
    history[histpos] = s;
    histpos++;
    if (histpos > clients.length)
        histpos = 0;
    for (int i = clients.length; --i >= 0;)
        try {
        if (clients[i] != null) {
        try {
            clients[i].print(s);
            clients[i].print("\n");
            clients[i].flush();
        } catch(Exception e) {
            removeListener(clients[i]);
        }
        }
        } catch(Exception e) {
        }

    }

    void converse(NetworkServer ns) {
    InputStream in = ns.clientInput;
    String clientName = null;
    char line[] = new char[1];
    try {
        while (true) {
        int c;
        int dp = 0;
        while ((c = in.read()) != -1 && c != '\n' && c != '\r') {
            if (dp >= line.length) {
            char nc[] = new char[line.length * 2];
            System.arraycopy(line, 0, nc, 0, line.length);
            line = nc;
            }
            line[dp++] = (char) c;
        }
        if (c < 0)
            break;
        if (dp <= 0)
            continue;
        String s = String.copyValueOf(line, 0, dp);
        if (clientName == null) {
            clientName = s;
            addListener(ns.clientOutput, clientName);
        } else {
            addString(clientName + ": " + s);
        }
        }
    } catch(Exception e) {
    }
    removeListener(ns.clientOutput);
    }
}