EventResignServiceImpl

gistfile1.java

package com.futureprocessing.fpcommunity.core.services.events;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.neo4j.template.Neo4jOperations;
import org.springframework.stereotype.Service;
import org.springframework.validation.Validator;
import com.futureprocessing.fpcommunity.core.datetime.IDateTime;
import com.futureprocessing.fpcommunity.core.domain.Event;
import com.futureprocessing.fpcommunity.core.domain.User;
import com.futureprocessing.fpcommunity.core.exceptions.EventEndedException;
import com.futureprocessing.fpcommunity.core.exceptions.UserNotAttendingEventException;
import com.futureprocessing.fpcommunity.core.services.impl.EventSatifsiesSearchedTextCriteriaPredicate;
import com.futureprocessing.fpcommunity.core.validation.groups.FulfilsPredicate;

@Service
public class EventResignServiceImpl implements IEventResignService {

    @Autowired
    private Neo4jOperations neo4jOperations;
    @Autowired
    private IDateTime dateTimeProvider;
    @Autowired
    private Validator validator;

    @Override
    public void resignFromEvent(@FulfilsPredicate(values = { EventSatifsiesSearchedTextCriteriaPredicate.class }) User resigningUser,
                                Event event) {
        fetchEventsAndParticipants(resigningUser, event);

        throwExceptionIfUserIsNotParticipatingEvent(resigningUser, event);
        throwExceptionIfEventIsInThePast(event);

        event.removeParticipant(resigningUser);
        resigningUser.removeAttendingEvent(event);
        neo4jOperations.save(resigningUser);
        neo4jOperations.save(event);
    }

    private void fetchEventsAndParticipants(User resigningUser, Event event) {
        neo4jOperations.fetch(resigningUser.getAttendingEvents());
        neo4jOperations.fetch(event.getParticipants());
    }

    private void throwExceptionIfUserIsNotParticipatingEvent(User resigningUser, Event event) {
        if (userIsNotParticipatingEvent(resigningUser, event)) {
            throw new UserNotAttendingEventException(resigningUser, event);
        }
    }

    private boolean userIsNotParticipatingEvent(User resigningUser, Event event) {
        return !(resigningUser.getAttendingEvents().contains(event) && event.getParticipants().contains(resigningUser));
    }

    private void throwExceptionIfEventIsInThePast(Event event) {
        if (eventIsInThePast(event)) {
            throw new EventEndedException(event);
        }
    }

    private boolean eventIsInThePast(Event event) {
        return event.getEndTime() < dateTimeProvider.getNow().getMillis();
    }
}