RequestFactory.java

package org.ggp.base.player.request.factory;

import java.util.ArrayList;
import java.util.List;

import org.ggp.base.player.gamer.Gamer;
import org.ggp.base.player.request.factory.exceptions.RequestFormatException;
import org.ggp.base.player.request.grammar.AbortRequest;
import org.ggp.base.player.request.grammar.InfoRequest;
import org.ggp.base.player.request.grammar.PlayRequest;
import org.ggp.base.player.request.grammar.PreviewRequest;
import org.ggp.base.player.request.grammar.Request;
import org.ggp.base.player.request.grammar.StartRequest;
import org.ggp.base.player.request.grammar.StopRequest;
import org.ggp.base.util.game.Game;
import org.ggp.base.util.gdl.factory.GdlFactory;
import org.ggp.base.util.gdl.factory.exceptions.GdlFormatException;
import org.ggp.base.util.gdl.grammar.GdlConstant;
import org.ggp.base.util.gdl.grammar.GdlTerm;
import org.ggp.base.util.symbol.factory.SymbolFactory;
import org.ggp.base.util.symbol.grammar.Symbol;
import org.ggp.base.util.symbol.grammar.SymbolAtom;
import org.ggp.base.util.symbol.grammar.SymbolList;

public final class RequestFactory
{
    public Request create(Gamer gamer, String source) throws RequestFormatException
    {
        try
        {
            SymbolList list = (SymbolList) SymbolFactory.create(source);
            SymbolAtom head = (SymbolAtom) list.get(0);

            String type = head.getValue().toLowerCase();
            if (type.equals("play"))
            {
                return createPlay(gamer, list);
            }
            else if (type.equals("start"))
            {
                return createStart(gamer, list);
            }
            else if (type.equals("stop"))
            {
                return createStop(gamer, list);
            }
            else if (type.equals("abort"))
            {
                return createAbort(gamer, list);
            }
            else if (type.equals("info"))
            {
                return createInfo(gamer, list);
            }
            else if (type.equals("preview"))
            {
                return createPreview(gamer, list);
            }
            else
            {
                throw new IllegalArgumentException("Unrecognized request type!");
            }
        }
        catch (Exception e)
        {
            throw new RequestFormatException(source, e);
        }
    }

    private PlayRequest createPlay(Gamer gamer, SymbolList list) throws GdlFormatException
    {
        if (list.size() != 3)
        {
            throw new IllegalArgumentException("Expected exactly 2 arguments!");
        }

        SymbolAtom arg1 = (SymbolAtom) list.get(1);
        Symbol arg2 = list.get(2);

        String matchId = arg1.getValue();
        List<GdlTerm> moves = parseMoves(arg2);

        return new PlayRequest(gamer, matchId, moves);
    }

    private StartRequest createStart(Gamer gamer, SymbolList list) throws GdlFormatException
    {
        if (list.size() < 6)
        {
            throw new IllegalArgumentException("Expected at least 5 arguments!");
        }

        SymbolAtom arg1 = (SymbolAtom) list.get(1);
        SymbolAtom arg2 = (SymbolAtom) list.get(2);
        SymbolList arg3 = (SymbolList) list.get(3);
        SymbolAtom arg4 = (SymbolAtom) list.get(4);
        SymbolAtom arg5 = (SymbolAtom) list.get(5);

        String matchId = arg1.getValue();
        GdlConstant roleName = (GdlConstant) GdlFactory.createTerm(arg2);
        String theRulesheet = arg3.toString();
        int startClock = Integer.valueOf(arg4.getValue());
        int playClock = Integer.valueOf(arg5.getValue());

        // For now, there are only five standard arguments. If there are any
        // new standard arguments added to START, they should be added here.

        Game theReceivedGame = Game.createEphemeralGame(theRulesheet);
        return new StartRequest(gamer, matchId, roleName, theReceivedGame, startClock, playClock);
    }

    private StopRequest createStop(Gamer gamer, SymbolList list) throws GdlFormatException
    {
        if (list.size() != 3)
        {
            throw new IllegalArgumentException("Expected exactly 2 arguments!");
        }

        SymbolAtom arg1 = (SymbolAtom) list.get(1);
        Symbol arg2 = list.get(2);

        String matchId = arg1.getValue();
        List<GdlTerm> moves = parseMoves(arg2);

        return new StopRequest(gamer, matchId, moves);
    }

    private AbortRequest createAbort(Gamer gamer, SymbolList list) throws GdlFormatException
    {
        if (list.size() != 2)
        {
            throw new IllegalArgumentException("Expected exactly 1 argument!");
        }

        SymbolAtom arg1 = (SymbolAtom) list.get(1);
        String matchId = arg1.getValue();

        return new AbortRequest(gamer, matchId);
    }

    private InfoRequest createInfo(Gamer gamer, SymbolList list) throws GdlFormatException
    {
        if (list.size() != 1)
        {
            throw new IllegalArgumentException("Expected no arguments!");
        }

        return new InfoRequest(gamer);
    }

    private PreviewRequest createPreview(Gamer gamer, SymbolList list) throws GdlFormatException
    {
        if (list.size() != 3)
        {
            throw new IllegalArgumentException("Expected exactly 2 arguments!");
        }

        SymbolAtom arg1 = (SymbolAtom) list.get(1);
        SymbolAtom arg2 = (SymbolAtom) list.get(2);

        String theRulesheet = arg1.toString();
        int previewClock = Integer.valueOf(arg2.getValue());

        Game theReceivedGame = Game.createEphemeralGame(theRulesheet);
        return new PreviewRequest(gamer, theReceivedGame, previewClock);
    }

    private List<GdlTerm> parseMoves(Symbol symbol) throws GdlFormatException
    {
        if (symbol instanceof SymbolAtom)
        {
            return null;
        }
        else
        {
            List<GdlTerm> moves = new ArrayList<GdlTerm>();
            SymbolList list = (SymbolList) symbol;

            for (int i = 0; i < list.size(); i++)
            {
                moves.add(GdlFactory.createTerm(list.get(i)));
            }

            return moves;
        }
    }
}