Add playerListMode config option

src/main/java/voruti/velocityplayerlistquery/model/Config.java

@@ -13,6 +13,7 @@ public class Config {
     public static final String FILE_NAME = "config.json";
 
     public static final Config DEFAULT = new ConfigBuilder()
+            .playerListMode(PlayerListMode.ADD)
             .serverListEntryFormat("%1$s")
             .maxListEntries(16)
             .replaceOnlinePlayerCount(false)
@@ -24,6 +25,16 @@ public class Config {
             .build();
 
 
+    /**
+     * Configure how players are shown in the player list.
+     *
+     * @see PlayerListMode#UNCHANGED
+     * @see PlayerListMode#ADD
+     * @see PlayerListMode#REPLACE
+     */
+    @Nullable
+    PlayerListMode playerListMode;
+
     /**
      * Configure how players are shown in the server list.
      * <ul>
@@ -76,4 +87,21 @@ public class Config {
      */
     @Nullable
     String versionName;
+
+
+    public enum PlayerListMode {
+        /**
+         * Keep the player list as it is.
+         */
+        UNCHANGED,
+        /**
+         * Add players to the player list.
+         * {@link #serverListEntryFormat} and {@link #maxListEntries} are only applied for the added players.
+         */
+        ADD,
+        /**
+         * Replace the player list with players according to {@link #serverListEntryFormat} and {@link #maxListEntries}.
+         */
+        REPLACE
+    }
 }

src/main/java/voruti/velocityplayerlistquery/service/serverpingprocessor/PlayerListServerPingProcessor.java

@@ -5,6 +5,8 @@
 import com.velocitypowered.api.proxy.server.ServerPing;
 import lombok.NonNull;
 import lombok.experimental.FieldDefaults;
+import voruti.velocityplayerlistquery.model.Config;
+import voruti.velocityplayerlistquery.model.Config.PlayerListMode;
 import voruti.velocityplayerlistquery.service.ConfigService;
 import voruti.velocityplayerlistquery.service.ServerListEntryBuilderService;
 
@@ -13,6 +15,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.EnumSet;
 import java.util.List;
 import java.util.UUID;
 import java.util.stream.Collectors;
@@ -34,10 +37,13 @@ public class PlayerListServerPingProcessor extends ServerPingProcessor {
 
     @Override
     public boolean isEnabled() {
-        return this.configService.getConfig().serverListEntryFormat() != null
+        final Config config = this.configService.getConfig();
+        final PlayerListMode playerListMode = config.playerListMode();
+
+        return playerListMode != null
+                && EnumSet.of(PlayerListMode.ADD, PlayerListMode.REPLACE).contains(playerListMode)
+                && config.serverListEntryFormat() != null
                 && !this.proxyServer.getAllPlayers().isEmpty();
-        // TODO: 3 options: keep player list, add to player list, replace player list; currently: add to
-        // TODO: .clearSamplePlayers()
     }
 
     @Override
@@ -55,9 +61,11 @@ public void applyToServerPing(@NonNull final ServerPing.Builder serverPing) {
                 // sort alphabetically:
                 .sorted(Comparator.comparing(ServerPing.SamplePlayer::getName));
 
+        final Config config = this.configService.getConfig();
+        final int maxListEntries = config.maxListEntries();
+
         // limit number of players shown in list, if configured:
         final List<ServerPing.SamplePlayer> samplePlayers;
-        final int maxListEntries = this.configService.getConfig().maxListEntries();
         if (maxListEntries > 0) {
             samplePlayers = playerStream
                     .limit(maxListEntries)
@@ -76,6 +84,10 @@ public void applyToServerPing(@NonNull final ServerPing.Builder serverPing) {
             samplePlayers = playerStream.collect(Collectors.toList());
         }
 
+        if (config.playerListMode() == PlayerListMode.REPLACE) {
+            serverPing.clearSamplePlayers();
+        }
+
         serverPing.samplePlayers(samplePlayers.toArray(new ServerPing.SamplePlayer[0]));
     }
 }