BP_ExtractorFactoryImpl.java

public final class ExtractorFactory<B> {
    private BiConsumer<B, ResultSet> consumer = (b, r) -> {};
    private Supplier<B> factory;

    public ExtractorFactory<B> factory(Supplier<B> factory) {
        this.factory = factory;
        return this;
    }

    public <T> ExtractorFactory<B> add(BiConsumer<B, T> setter,
        BiFunction<ResultSet, Integer, T> getter, Integer index) {
        final Extraction<B, T> extraction =
            new Extraction<>(setter, getter, index);
        consumer = consumer.andThen(extraction);
        return this;
    }

    public Extractor<B> getExtractor() {
        return new GeneratedExtractor<>(factory, consumer);
    }

    private static class GeneratedExtractor<B> implements Extractor<B> {
        private final Supplier<B> factory;
        private final BiConsumer<B, ResultSet> consumer;

        GeneratedExtractor(Supplier<B> factory,
             BiConsumer<B, ResultSet> consumer) {
            this.factory = factory;
            this.consumer = consumer;
        }

        @Override
        public B extract(ResultSet rs) throws SQLException {
            final B bean = factory.get();
            consumer.accept(bean, rs);
            return bean;
        }
    }

    private static class Extraction<B, T> implements BiConsumer<B, ResultSet> {
        final BiConsumer<B, T> setter;
        final BiFunction<ResultSet, Integer, T> getter;
        final Integer index;

        Extraction(BiConsumer<B, T> setter,
            BiFunction<ResultSet, Integer, T> getter, Integer index) {
            this.setter = setter;
            this.getter = getter;
            this.index = index;
        }

        @Override
        public void accept(B bean, ResultSet resultSet) {
            setter.accept(bean, getter.apply(resultSet, index));
        }
    }

}