source: src/main/java/negotiator/parties/HillClimber.java@ 48

package negotiator.parties;

import java.util.List;

import genius.core.AgentID;
import genius.core.Vote;
import genius.core.actions.Action;
import genius.core.actions.InformVotingResult;
import genius.core.actions.OfferForVoting;
import genius.core.actions.VoteForOfferAcceptance;
import genius.core.parties.AbstractNegotiationParty;
import genius.core.parties.NegotiationInfo;
import genius.core.parties.NegotiationParty;
import genius.core.protocol.DefaultMultilateralProtocol;
import genius.core.protocol.MediatorProtocol;
import genius.core.protocol.MultilateralProtocol;

/**
 * Implementation of a party that uses hill climbing strategy to get to an
 * agreement.
 * <p/>
 * This party should be run with {@link genius.core.protocol.MediatorProtocol}
 *
 * @author David Festen
 * @author Reyhan
 */
public class HillClimber extends AbstractNegotiationParty {

        private double lastAcceptedBidUtility;

        private double lastReceivedBidUtility;

        private Vote currentVote;

        /**
         * Initializes a new instance of the {@link HillClimber} class.
         *
         * @param utilitySpace
         *            The utility space used by this class
         * @param deadlines
         *            The deadlines for this session
         * @param timeline
         *            The time line (if time deadline) for this session, can be null
         * @param randomSeed
         *            The seed that should be used for all randomization (to be
         *            reproducible)
         */
        @Override
        public void init(NegotiationInfo info) {
                super.init(info);
                lastAcceptedBidUtility = 0;
                lastReceivedBidUtility = 0;
                currentVote = Vote.REJECT;
        }

        /**
         * When this class is called, it is expected that the Party chooses one of
         * the actions from the possible action list and returns an instance of the
         * chosen action. This class is only called if this {@link NegotiationParty}
         * is in the
         * {@link negotiator.protocol .DefaultProtocol#getRoundStructure(java.util.List, negotiator.session.Session)}
         * .
         *
         * @param possibleActions
         *            List of all actions possible.
         * @return The chosen action
         */
        @Override
        public Action chooseAction(List<Class<? extends Action>> possibleActions) {
                return new VoteForOfferAcceptance(getPartyId(), currentVote);
        }

        /**
         * This method is called when an observable action is performed. Observable
         * actions are defined in
         * {@link MultilateralProtocol#getActionListeners(java.util.List)}
         *
         * @param sender
         *            The initiator of the action
         * @param arguments
         *            The action performed
         */
        @Override
        public void receiveMessage(AgentID sender, Action arguments) {
                if (arguments instanceof OfferForVoting) {
                        lastReceivedBidUtility = getUtility(((OfferForVoting) arguments).getBid());
                        double reservationValue = (timeline == null) ? utilitySpace.getReservationValue()
                                        : utilitySpace.getReservationValueWithDiscount(timeline);

                        if (lastReceivedBidUtility < reservationValue) {
                                currentVote = Vote.REJECT;
                        } else {
                                currentVote = lastReceivedBidUtility >= lastAcceptedBidUtility ? Vote.ACCEPT : Vote.REJECT;
                        }
                } else if (arguments instanceof InformVotingResult) {
                        if (((InformVotingResult) arguments).getVotingResult() == Vote.ACCEPT) {
                                lastAcceptedBidUtility = lastReceivedBidUtility;
                        }
                }
        }

        @Override
        public Class<? extends DefaultMultilateralProtocol> getProtocol() {
                return MediatorProtocol.class;
        }

        @Override
        public String getDescription() {
                return "Hill Climber Party";
        }
}