refactoring

wizard-server/src/main/java/eu/jonahbauer/wizard/server/Lobby.java

@@ -21,6 +21,7 @@ public class Lobby {
 
     private final Map<UUID, Session> sessions = new ConcurrentHashMap<>();
     private final List<Player> players = new ArrayList<>();
+    // read lock is required whenever players are read or sessions are modified, write lock is required when players are modified
     private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
 
     private Lobby() {}
@@ -79,6 +80,9 @@ public class Lobby {
         }
     }
 
+    /**
+     * Adds a player to the lobby.
+     */
     public void join(Player player) {
         lock.writeLock().lock();
         try {
@@ -89,6 +93,11 @@ public class Lobby {
         }
     }
 
+    /**
+     * Removes a player from the lobby. It is ensured that no further lobby related messages
+     * ({@link SessionCreatedMessage}, {@link SessionModifiedMessage}, {@link SessionRemovedMessage}) are set to this
+     * player after the call to this method returns.
+     */
     public void leave(Player player) {
         lock.writeLock().lock();
         try {