Add EventInterface prototype

src/main/java/net/minestom/server/event/EventInterface.java

@@ -0,0 +1,35 @@
+package net.minestom.server.event;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+public final class EventInterface<T> {
+
+    public static <T> @NotNull Builder<T> builder(@NotNull Class<T> type) {
+        return new Builder<>();
+    }
+
+    final Map<Class<? extends Event>, BiConsumer<T, Event>> mapped;
+
+    EventInterface(Map<Class<? extends Event>, BiConsumer<T, Event>> map) {
+        this.mapped = map;
+    }
+
+    public static class Builder<T> {
+        private final Map<Class<? extends Event>, BiConsumer<T, Event>> mapped = new HashMap<>();
+
+        @SuppressWarnings("unchecked")
+        public <E extends Event> Builder<T> map(@NotNull Class<E> eventType,
+                                                @NotNull BiConsumer<@NotNull T, @NotNull E> consumer) {
+            this.mapped.put(eventType, (BiConsumer<T, Event>) consumer);
+            return this;
+        }
+
+        public @NotNull EventInterface<T> build() {
+            return new EventInterface<>(Map.copyOf(mapped));
+        }
+    }
+}

src/main/java/net/minestom/server/event/EventNode.java

@@ -514,6 +514,13 @@ public class EventNode<T extends Event> {
         return this;
     }
 
+    public <I> void addInter(@NotNull EventInterface<I> inter, @NotNull I value) {
+        inter.mapped.forEach((eventType, consumer) -> {
+            // TODO cache so listeners can be removed from the EventInterface
+            addListener((EventListener<? extends T>) EventListener.builder(eventType).handler(event -> consumer.accept(value, event)).build());
+        });
+    }
+
     private void increaseChildListenerCount(Class<? extends T> eventClass, int count) {
         var entry = listenerMap.computeIfAbsent(eventClass, aClass -> new ListenerEntry<>());
         ListenerEntry.addAndGet(entry, count);