The Net: Ultimate Internet Guide/WWLCD1.ISO/pc/java/enxle1f6/src/games/battle/shared/comm/gameinfo.java

Java Source | 1996-08-14 | 4.8 KB | 217 lines

/*
 * @(#)GameInfo.java
 */
package games.Battle.shared.comm;

import java.io.*;

/**
 * GameInfo encapsulates all the knowledge about a particular game on the
 * server. The GameInfo packet knows which players have joined the game,
 * how many are still needed to start the game, and what the gameId of
 * the game is.
 * <P>
 * The server transmits a series of GameInfo packets to the client so that
 * the user can choose which game they would like to join. Once a game is
 * full of players, the game is automatically started by the server, and
 * the players can only quit by forfeiting the game.
 *
 * @version 1.00
 * @author Alex Nicolaou
 * @author Jay Steele
 */

public class GameInfo extends BattlePacket {
    /**
     * The game will start when numPlayersNeeded players have joined.
     */
    byte numPlayersNeeded;
    /**
     * The game keeps a count of how many players have joined so far.
     */
    byte numPlayersIn;
    /**
     * The game has a unique ID number so that the client and server can
     * refer to it unambigously across the network.
     */
    byte gameId;

    /**
     * The game ID is always generated by the server, using this static
     * counter to ensure that each new game ID is unique.
     */
    static byte gameIdCounter = 0;

    /**
     * The game keeps an array of players that have joined so far.
     */
    public PlayerInfo[] players;

    /**
     * Construct an empty GameInfo packet so that it can be read from an
     * input stream.
     */
    public GameInfo() {
        numPlayersNeeded = 0;
        numPlayersIn = 0;
        gameId = 0;
    }

    /**
     * Construct a new GameInfo packet, including making a new ID.
     * @param numPlayers the number of players needed to start this game
     */
    public GameInfo(int numPlayers) {
        numPlayersNeeded = (byte)numPlayers;
        numPlayersIn = 0;
        gameId = gameIdCounter;
        gameIdCounter++;

        players = new PlayerInfo[numPlayersNeeded];
    }

    /**
     * Returns true if the game is full of all the players it needs.
     */
    public boolean isRunning() {
        return numPlayersIn == numPlayersNeeded;
    }

    /**
     * Empties all the players out of this game.
     */
    public synchronized void reset() {
        for (int i = 0; i < numPlayersNeeded; i++)
            players[i] = null;
        numPlayersIn = 0;
    }

    /**
     * Allows a new player to join this game.
     */
    public synchronized void join(PlayerInfo p) {
        for (int i = 0; i < numPlayersIn; i++)
            if (players[i].sameId(p))
                return; // can't join game twice!

        if (!isRunning()) {
            players[numPlayersIn] = p;
            numPlayersIn++;
        }
    }

    /**
     * Allows a player to get out of this game.
     */
    public synchronized void quit(PlayerInfo p) {
        if (isRunning())
            return;

        for (int i = 0; i < numPlayersIn; i++)
            if (players[i].sameId(p)) {
                numPlayersIn--;
                players[i] = players[numPlayersIn];
                players[numPlayersIn] = null;
                return;
            }
    }

    /**
     * Returns how many players are needed to fill this game.
     */
    public int numberNeeded() {
        return numPlayersNeeded;
    }

    /**
     * Returns how many players have joined this game.
     */
    public int numberJoined() {
        return numPlayersIn;
    }

    /**
     * Returns this game's unique identifier
     */
    public int getId() {
        return gameId;
    }

    /**
     * Produce an array of bytes representing a GameInfo
     */
    public byte[] toBytes() {
        byte[] buffer = new byte[3];
        buffer[0] = numPlayersNeeded;
        buffer[1] = numPlayersIn;
        buffer[2] = gameId;

        return buffer;
    }

    /**
     * Produce a GameInfo from an array of bytes.
     */
    public void fromBytes(byte[] buffer) {
        numPlayersNeeded = buffer[0];
        numPlayersIn = buffer[1];
        gameId = buffer[2];

        players = new PlayerInfo[numPlayersNeeded];
    }

    /**
     * Write this GameInfo to the OutputStream given. Overrides the
     * base class so that we can easily write out the embedded PlayerInfo
     * objects.
     * @param os the output stream that the info packet is written to
     */
    public void writeTo(OutputStream os) throws java.io.IOException {
        super.writeTo(os);
        for (int i = 0; i < numPlayersIn; i++) {
            players[i].writeTo(os);
        }
    }

    /**
     * Read this GameInfo from the InputStream given. Overrides the
     * base class so that we can easily read in the embedded PlayerInfo
     * objects.
     * @param is the input stream that the info packet is read from
     */
    public int readFrom(InputStream is) throws java.io.IOException {
        int size = super.readFrom(is);

        for (int i = 0; i < numPlayersIn; i++) {
            players[i] = new PlayerInfo();
            size += players[i].readFrom(is);
        }

        return size;
    }

    /**
     * Returns a string representation of this game.
     */
    public String toString() {
        return "Game needs " + numPlayersNeeded + ", has " + numPlayersIn;
    }

    public int hashCode() {
        return gameId;
    }

    public boolean equals(Object other) {
        boolean ret = false;
        try {
            GameInfo o = (GameInfo)other;
            if (o.getId() == gameId)
                ret = true;
        }
        catch (Exception e) {
            ret = false;
        }
        return ret;
    }
}