From 741f9073488c9963036309ed7b5367ca2ab30c3e Mon Sep 17 00:00:00 2001
From: Yannik Bretschneider <ybretsch@gmail.com>
Date: Wed, 26 May 2021 13:57:47 +0200
Subject: [PATCH] feat: changed pipeline return type to optional for better
 clarity, and added comments

---
 Gamelib                                       |  2 +-
 .../server/Lobby/pipelining/Pipeline.java     | 30 +++++++++++++------
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/Gamelib b/Gamelib
index a4c5102..65c33d8 160000
--- a/Gamelib
+++ b/Gamelib
@@ -1 +1 @@
-Subproject commit a4c510279a35bfd10da62b3026eb2ed4c3c369ad
+Subproject commit 65c33d886c9c8f2d4a06356f32ad6d772b60e7ee
diff --git a/Server/src/main/java/uulm/teamname/marvelous/server/Lobby/pipelining/Pipeline.java b/Server/src/main/java/uulm/teamname/marvelous/server/Lobby/pipelining/Pipeline.java
index 8f1cee2..bcfe4ff 100644
--- a/Server/src/main/java/uulm/teamname/marvelous/server/Lobby/pipelining/Pipeline.java
+++ b/Server/src/main/java/uulm/teamname/marvelous/server/Lobby/pipelining/Pipeline.java
@@ -7,6 +7,7 @@ import uulm.teamname.marvelous.gamelibrary.requests.Request;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
@@ -32,22 +33,33 @@ public class Pipeline {
      * {@link Event events} relevant to the {@link Segment segment}. The {@link Event Events} are returned at the
      * end of the pipeline.
      * @param requests are the requests that are being pipelined through the pipeline
-     * @return a {@link Tuple}<{@link Boolean}, {@link Event}[]>, whereby the {@link Boolean} declares whether the
-     *         execution of the {@link Pipeline} is successful. <b>If that is the case, the events can be ignored,
-     *         and an error message can be sent to the client</b>.
+     * @return a {@link Optional}<{@link Event}[]>, whereby the state of the {@link Optional} declares whether the
+     *         execution of the {@link Pipeline} was successful. <b>If the optional is empty, the input requests were
+     *         invalid, and an error message can be sent to the client</b>. To get the {@link Event Events}
+     *         out of the {@link Optional}, first check whether the {@link Optional} is empty by doing
+     *         {@link Optional#isEmpty()} or {@link Optional#isPresent()}, and act accordingly.
      */
-    public Tuple<Boolean, Event[]> processRequests(Request[] requests) {
+    public Optional<Event[]> processRequests(Request[] requests) {
+        // The packet carries the requests, and gets smaller per segment
         List<Request> packet = Arrays.asList(requests);
+        // The packet is filled by the requests resulting from events per segment
         List<Event> carrier = new ArrayList<>();
-        AtomicBoolean abort = new AtomicBoolean();
-        abort.set(false);
+        // The abort boolean describes whether an abort happened in a segment
+        AtomicBoolean abort = new AtomicBoolean(false);
+
+        // Loop through all segments
         for (Segment segment: segments) {
+            // Give the segment the packet, carrier and abort, and let it process requests
             segment.processRequests(packet, carrier, abort);
-            if (packet.size() == 0 || abort.get()) {
-                break;
+            if (packet.size() == 0 || abort.get()) { // if packet is empty (all requests processed) or abort initiated
+                break;                               // (abort boolean true), break out of the loop
             }
         }
-        return new Tuple<Boolean, Event[]> (abort.get(), carrier.toArray(new Event[0]));
+        if (abort.get()) { // if abort is true, return empty optional
+            return Optional.empty();
+        } else { // else return an optional of the array
+            return Optional.of(carrier.toArray(new Event[0]));
+        }
     }
 
     /**