return result;
}
+ /**
+ * Given a {@link Collection} of {@link Conversation}s, builds a {@link Map} from {@link String} to {@link List}
+ * of {@link Conversation}s such that each key is the <em>concatenation of the packet lengths of all payload packets
+ * (i.e., the set of packets returned by {@link Conversation#getPackets()}) separated by a delimiter</em> of any
+ * {@link Conversation} pointed to by that key. In other words, what the {@link Conversation}s {@code cs} pointed to
+ * by the key {@code s} have in common is that they all contain exactly the same number of payload packets <em>and
+ * </em> these payload packets are identical across all {@code Conversation}s in {@code convs} in terms of packet
+ * length and packet order. For example, if the key is "152 440 550", this means that every individual
+ * {@code Conversation} in the list of {@code Conversation}s pointed to by that key contain exactly three payload
+ * packet of lengths 152, 440, and 550, and these three packets are ordered the in the order prescribed by the key.
+ *
+ * @param conversations The collection of {@code Conversation}s to group by packet sequence.
+ * @return a {@link Map} from {@link String} to {@link List} of {@link Conversation}s such that each key is the
+ * <em>concatenation of the packet lengths of all payload packets (i.e., the set of packets returned by
+ * {@link Conversation#getPackets()}) separated by a delimiter</em> of any {@link Conversation} pointed to
+ * by that key.
+ */
+ public static Map<String, List<Conversation>> groupConversationsByPacketSequence(Collection<Conversation> conversations) {
+ Map<String, List<Conversation>> result = new HashMap<>();
+ for (Conversation conv : conversations) {
+ if (conv.getPackets().size() == 0) {
+ // Skip conversations with no payload packets.
+ continue;
+ }
+ StringBuilder sb = new StringBuilder();
+ for (PcapPacket pp : conv.getPackets()) {
+ if (sb.length() != 0) {
+ // only add a space if there's preceding content
+ sb.append(" ");
+ }
+ sb.append(pp.length());
+ }
+ List<Conversation> oneItemList = new ArrayList<>();
+ oneItemList.add(conv);
+ result.merge(sb.toString(), oneItemList, (oldList, newList) -> {
+ oldList.addAll(newList);
+ return oldList;
+ });
+ }
+ return result;
+ }
+
/**
* Given a {@link Conversation}, counts the frequencies of each unique packet length seen as part of the
* {@code Conversation}.