Lambda / Optional demos

OptionalDemo.java

    private static <T> boolean fillIf(final Supplier<T> supplier, final Consumer<T> consumer) {
        return fillIf(supplier, consumer, null);
    }

    private static <T> boolean fillIf(final Supplier<? extends T> supplier, final Consumer<T> consumer, final Consumer<Exception> exceptionHandler) {
        try {
            final T data = supplier.get();
            if (null == data) {
                return false;
            }
            consumer.accept(data);
            return true;
        } catch (final Exception e) {
            if (exceptionHandler != null) {
                exceptionHandler.accept(e);
            }
            return false;
        }
    }

    private static Optional<Matcher> ifFound(final Pattern pattern, final String text, final Consumer<Matcher> consumer) {
        final Matcher m = pattern.matcher(text);
        if (m.find()) {
            consumer.accept(m);
            return Optional.of(m);
        }
        return Optional.empty();
    }

    private static <T> Optional<T> transform(final Pattern pattern, final String text, final Function<Matcher, T> transformer) {
        final Matcher m = pattern.matcher(text);
        if (m.find()) {
            return Optional.of(transformer.apply(m));
        } else {
            return Optional.empty();
        }
    }