+ /**
+ * Container for input and output counters.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+ public static class TrafficCounter {
+
+ /** The number of input bytes. */
+ private final long input;
+
+ /** The number of output bytes. */
+ private final long output;
+
+ /**
+ * Creates a new traffic counter.
+ *
+ * @param input
+ * The number of input bytes (may be {@code -1} to signify non-available
+ * input)
+ * @param output
+ * The number of output bytes (may be {@code -1} to signify non-available
+ * output)
+ */
+ public TrafficCounter(long input, long output) {
+ this.input = input;
+ this.output = output;
+ }
+
+ //
+ // ACCESSORS
+ //
+
+ /**
+ * Returns the number of input bytes.
+ *
+ * @return The number of input bytes, or {@link Optional#absent()} if the
+ * component can not receive input
+ */
+ public Optional<Long> input() {
+ return (input == -1) ? Optional.<Long>absent() : Optional.of(input);
+ }
+
+ /**
+ * Returns the number of output bytes.
+ *
+ * @return The number of output bytes, or {@link Optional#absent()} if the
+ * component can not send output
+ */
+ public Optional<Long> output() {
+ return (output == -1) ? Optional.<Long>absent() : Optional.of(output);
+ }
+
+ }
+