From 9177e94d1bc7f22a27fb8c8428cf02a40128ed3a Mon Sep 17 00:00:00 2001
From: TheMode <themode@outlook.fr>
Date: Thu, 3 Jun 2021 21:39:38 +0200
Subject: [PATCH] Allow node predicate based on tag

---
 .../java/net/minestom/server/event/EventNode.java  | 14 ++++++++++++++
 src/test/java/demo/PlayerInit.java                 |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/src/main/java/net/minestom/server/event/EventNode.java b/src/main/java/net/minestom/server/event/EventNode.java
index 8d564ad28..25d06e988 100644
--- a/src/main/java/net/minestom/server/event/EventNode.java
+++ b/src/main/java/net/minestom/server/event/EventNode.java
@@ -2,8 +2,11 @@ package net.minestom.server.event;
 
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
 import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
+import net.minestom.server.tag.Tag;
+import net.minestom.server.tag.TagReadable;
 import net.minestom.server.utils.validate.Check;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
@@ -38,6 +41,17 @@ public class EventNode<T extends Event> {
         return predicate(filter, (e, h) -> predicate.test(h));
     }
 
+    public static <E extends Event, V extends TagReadable> EventNode<E> predicateTag(@NotNull EventFilter<E, V> filter,
+                                                                                     @NotNull Tag<?> tag) {
+        return predicate(filter, (e, h) -> h.hasTag(tag));
+    }
+
+    public static <E extends Event, V extends TagReadable, V2> EventNode<E> predicateTag(@NotNull EventFilter<E, V> filter,
+                                                                                         @NotNull Tag<V2> tag,
+                                                                                         @NotNull Predicate<@Nullable V2> consumer) {
+        return predicate(filter, (e, h) -> consumer.test(h.getTag(tag)));
+    }
+
     private final Map<Class<? extends T>, List<EventListener<T>>> listenerMap = new ConcurrentHashMap<>();
     private final Map<Object, EventNode<T>> redirectionMap = new ConcurrentHashMap<>();
     private final Set<EventNode<T>> children = new CopyOnWriteArraySet<>();
diff --git a/src/test/java/demo/PlayerInit.java b/src/test/java/demo/PlayerInit.java
index 3f4657242..672fa7285 100644
--- a/src/test/java/demo/PlayerInit.java
+++ b/src/test/java/demo/PlayerInit.java
@@ -35,6 +35,7 @@ import net.minestom.server.item.metadata.CompassMeta;
 import net.minestom.server.monitoring.BenchmarkManager;
 import net.minestom.server.monitoring.TickMonitor;
 import net.minestom.server.network.ConnectionManager;
+import net.minestom.server.tag.Tag;
 import net.minestom.server.utils.MathUtils;
 import net.minestom.server.utils.Position;
 import net.minestom.server.utils.Vector;
@@ -152,6 +153,8 @@ public class PlayerInit {
         var conditional = EventNode.predicateValue(EventFilter.PLAYER, Player::isCreative)
                 .addListener(PlayerMoveEvent.class, (event) -> System.out.println("creative player moved"));
 
+        var tagNode = EventNode.predicateTag(EventFilter.ITEM, Tag.String("tag"), s -> s != null && !s.isEmpty());
+
         node.addChild(conditional);
         node.call(new PlayerTickEvent(null));