Factor list concatenation

2 files changed, 17 insertions, 4 deletions

diff --git a/src/ch/epfl/xblast/Lists.java b/src/ch/epfl/xblast/Lists.java
index b943162..073e0cc 100644
--- a/src/ch/epfl/xblast/Lists.java
+++ b/src/ch/epfl/xblast/Lists.java
@@ -152,4 +152,19 @@ public final class Lists {
         return new ArrayList<>(l.subList(n, l.size()));
     }
 
+    /**
+     * Returns an immutable copy of the given lists, concatenated.
+     *
+     * @param lists the lists to concatenate
+     * @param <T>   the type of the list's elements
+     * @return the list result of the concatenation
+     */
+    public static <T> List<T> concatenated(List<T>... lists) {
+        return Collections.unmodifiableList(
+                Stream.of(lists)
+                        .map(List::stream)
+                        .reduce(Stream::concat).orElse(Stream.empty())
+                        .collect(Collectors.toList()));
+    }
+
 }
diff --git a/src/ch/epfl/xblast/server/GameStateSerializer.java b/src/ch/epfl/xblast/server/GameStateSerializer.java
index a24ed95..df448a5 100644
--- a/src/ch/epfl/xblast/server/GameStateSerializer.java
+++ b/src/ch/epfl/xblast/server/GameStateSerializer.java
@@ -10,7 +10,6 @@ import ch.epfl.xblast.server.painter.PlayerPainter;
 
 import java.util.*;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 /**
  * The game state serializer that serializes a GameState into a byte sequence
@@ -144,12 +143,11 @@ public final class GameStateSerializer {
      * @return the serialized GameState
      */
     public static List<Byte> serialize(BoardPainter bp, GameState gs) {
-        return Collections.unmodifiableList(Stream.of(
+        return Lists.concatenated(
                 compress(serializeBoard(bp, gs.board())),
                 compress(serializeExplosions(gs.bombedCells(), gs.blastedCells(), gs.board())),
                 serializePlayers(gs.players(), gs.ticks()),
-                serializeRemainingTime(gs.remainingTime())
-        ).flatMap(List::stream).collect(Collectors.toList()));
+                serializeRemainingTime(gs.remainingTime()));
     }
 
 }