extract(sourceModel, head, st -> sink.add(st), contexts); return sink;
GetStatementOptional statementSupplier = (s, p, o, c) -> ((Model)sourceModel).filter(s, p, o, c).stream().findAny(); extract(statementSupplier, head, consumer, Models::modelException, contexts);
Function<String, Supplier<ModelException>> exceptionSupplier = Models::modelException; extract(statementSupplier, head, st -> { if (RDF.FIRST.equals(st.getPredicate())) { consumer.accept(st.getObject());