source: src/main/java/genius/core/protocol/MediatorProtocol.java

package genius.core.protocol;

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

import genius.core.parties.Mediator;
import genius.core.parties.NegotiationParty;

/**
 * Base class for all mediator-based protocols
 *
 * @author David Festen
 */
public abstract class MediatorProtocol extends DefaultMultilateralProtocol {

        /**
         * Returns the first mediator from a list of parties
         *
         * @param parties
         *            The list of parties to find the mediator in
         * @return The first mediator in the given list, or null if no such entity
         *         exists.
         */
        public static Mediator getMediator(List<NegotiationParty> parties) {

                // Mediator should be first item, but this should find it wherever it
                // is.
                for (NegotiationParty party : parties) {
                        if (party instanceof Mediator) {
                                return (Mediator) party;
                        }
                }

                // default case, no mediator found, return null
                return null;
        }

        /**
         * Get the non-mediator parties. assumption: there are only zero or one
         * mediators in the list
         *
         * @param parties
         *            The list of parties with mediator
         * @return The given without the mediators
         */
        public static List<NegotiationParty> getNonMediators(List<NegotiationParty> parties) {

                List<NegotiationParty> nonMediators = new ArrayList<NegotiationParty>(parties);
                nonMediators.remove(getMediator(parties));
                return nonMediators;
        }

}