presto-main/src/main/java/io/prestosql/operator/JoinHash.java/JoinHash/JoinHash
class JoinHash:    public JoinHash(PagesHash pagesHash, Optional<JoinFilterFunction> filterFunction, Optional<PositionLinks> positionLinks)
    {
        this.pagesHash = requireNonNull(pagesHash, "pagesHash is null");
        this.filterFunction = requireNonNull(filterFunction, "filterFunction can not be null").orElse(null);
        this.positionLinks = requireNonNull(positionLinks, "positionLinks is null").orElse(null);
    }