@VisibleForTesting JoinEnumerator(CostComparator costComparator, Expression filter, Context context) { this.context = requireNonNull(context); this.session = requireNonNull(context.getSession(), "session is null"); this.costProvider = requireNonNull(context.getCostProvider(), "costProvider is null"); this.resultComparator = costComparator.forSession(session).onResultOf(result -> result.cost); this.idAllocator = requireNonNull(context.getIdAllocator(), "idAllocator is null"); this.allFilter = requireNonNull(filter, "filter is null"); this.allFilterInference = createEqualityInference(filter); this.lookup = requireNonNull(context.getLookup(), "lookup is null"); }