Initial EventContext prototype

Signed-off-by: TheMode <themode@outlook.fr>

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

@@ -0,0 +1,19 @@
+package net.minestom.server.event;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Map;
+
+public interface EventContext<E extends Event> {
+    <T> @NotNull T filter(@NotNull EventFilter<? super E, T> filter);
+
+    void mutate(@NotNull E event);
+
+    @NotNull EventNode<? super E> currentNode();
+
+    int executionCount();
+
+    static <E extends Event> EventContext<E> filters(Map<EventFilter<? super E, ?>, ?> filters) {
+        throw new UnsupportedOperationException();
+    }
+}

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

@@ -10,6 +10,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.List;
 import java.util.Set;
+import java.util.function.BiConsumer;
 import java.util.function.BiPredicate;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
@@ -358,4 +359,14 @@ public sealed interface EventNode<T extends Event> permits EventNodeImpl {
 
     @ApiStatus.Experimental
     void unregister(@NotNull EventBinding<? extends T> binding);
+
+    default <E extends T> E call(@NotNull EventContext<E> context, @NotNull E event) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Contract(value = "_, _ -> this")
+    default <E extends Event> @NotNull EventNode<T> addListener(@NotNull Class<E> eventType,
+                                                                @NotNull BiConsumer<EventContext<E>, E> listener) {
+        throw new UnsupportedOperationException();
+    }
 }

src/test/java/net/minestom/server/event/EventRecordTest.java

@@ -0,0 +1,52 @@
+package net.minestom.server.event;
+
+import net.minestom.server.coordinate.Pos;
+import net.minestom.server.event.trait.ItemEvent;
+import net.minestom.server.item.ItemStack;
+import net.minestom.server.item.Material;
+import org.jetbrains.annotations.NotNull;
+import org.junit.jupiter.api.Test;
+
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class EventRecordTest {
+
+    record ActionAt(Pos position) implements ItemEvent {
+        @Override
+        public @NotNull ItemStack getItemStack() {
+            // FIXME: Will be removed, as events will not be responsible for the filters anymore
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    @Test
+    public void testCall() {
+        var node = EventNode.all("main");
+        ItemStack item = ItemStack.of(Material.DIAMOND);
+        var action = new ActionAt(Pos.ZERO);
+        var mutated = new ActionAt(new Pos(1, 1, 1));
+        node.addListener(ActionAt.class, (context, event) -> {
+            assertEquals(action, event);
+
+            ItemStack filter = context.filter(EventFilter.ITEM);
+            assertEquals(item, filter);
+            assertEquals(0, context.executionCount());
+            assertEquals(node, context.currentNode());
+            context.mutate(mutated);
+        });
+        ActionAt result = node.call(EventContext.filters(Map.of(EventFilter.ITEM, item)), action);
+        assertEquals(mutated, result);
+    }
+
+    @Test
+    public void currentNode() {
+        var node = EventNode.all("main");
+        node.addListener(ActionAt.class, (context, event) -> {
+            var current = context.currentNode();
+            assertEquals(node, current);
+        });
+        node.call(EventContext.filters(Map.of()), new ActionAt(Pos.ZERO));
+    }
+}