class ForeCastMatcher extends GenericMatchEngine {
        @Override
        protected AbstractSimilarityChecker prepareChecker() {
            return new AbstractSimilarityChecker(filter) {

                @Override
                public boolean isSimilar(EObject obj1, final EObject obj2)
                        throws FactoryException {
                    WorldcupforecastSwitch<Boolean> comparison = new WorldcupforecastSwitch<Boolean>() {

                        @Override
                        public Boolean caseForecast(Forecast object) {
                            return EcoreUtil.equals(object.getMatch(),
                                    ((Forecast) obj2).getMatch());
                        }

                        @Override
                        public Boolean caseForecastDay(ForecastDay object) {

                            return object.getDate().equals(
                                    ((ForecastDay) obj2).getDate());
                        }

                        @Override
                        public Boolean casePlayer(Player object) {
                            return true;
                        }
                    };
                    return comparison.doSwitch(obj1);
                }

                @Override
                public double absoluteMetric(EObject obj1, EObject obj2)
                        throws FactoryException {
                    if (isSimilar(obj1, obj2)) {
                        return 1.0;
                    }
                    return 0;
                }

                @Override
                public void init(Resource leftResource, Resource rightResource)
                        throws FactoryException {

                }

                @Override
                public void init(EObject leftObject, EObject rightObject)
                        throws FactoryException {
                }

            };
        }
    }