implement FunctionalEventHandler

common/addons/biome-provider-pipeline/src/main/java/com/dfsek/terra/addons/biome/pipeline/BiomePipelineAddon.java

@@ -26,6 +26,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.util.reflection.TypeKey;
 import com.dfsek.terra.api.world.biome.generation.BiomeProvider;
@@ -44,7 +45,8 @@ public class BiomePipelineAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> event.getPack().applyLoader(BIOME_SOURCE_BUILDER_TOKEN.getType(), new SourceLoader())
                         .applyLoader(Stage.class, new StageLoader())
                         .applyLoader(ExpanderStage.Type.class, (c, o, l) -> ExpanderStage.Type.valueOf((String) o))

common/addons/chunk-generator-noise-3d/src/main/java/com/dfsek/terra/addons/chunkgenerator/NoiseChunkGenerator3DAddon.java

@@ -12,6 +12,7 @@ import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.ConfigurationLoadEvent;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.world.biome.TerraBiome;
 import com.dfsek.terra.api.world.generator.ChunkGeneratorProvider;
@@ -26,7 +27,8 @@ public class NoiseChunkGenerator3DAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     event.getPack().getOrCreateRegistry(ChunkGeneratorProvider.class).register("NOISE_3D", pack -> new NoiseChunkGenerator3D(pack, main));
                     event.getPack()
@@ -36,7 +38,8 @@ public class NoiseChunkGenerator3DAddon extends TerraAddon {
                 .failThrough();
 
         main.getEventManager()
-                .register(ConfigurationLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigurationLoadEvent.class)
                 .then(event -> {
                     if(event.is(TerraBiome.class)) {
                         event.getLoadedObject(TerraBiome.class).getContext().put(event.load(new BiomePaletteTemplate()).get());

common/addons/config-biome/src/main/java/com/dfsek/terra/addons/biome/BiomeAddon.java

@@ -8,6 +8,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 
 @Addon("config-biome")
@@ -20,7 +21,8 @@ public class BiomeAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     event.getPack().registerConfigType(new BiomeConfigType(event.getPack()), "BIOME", 5);
                     event.getPack().applyLoader(PaletteHolder.class, new PaletteHolderLoader());

common/addons/config-distributors/src/main/java/com/dfsek/terra/addons/feature/distributor/DistributorAddon.java

@@ -11,6 +11,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.registry.CheckedRegistry;
 import com.dfsek.terra.api.structure.feature.Distributor;
@@ -29,7 +30,8 @@ public class DistributorAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     CheckedRegistry<Supplier<ObjectTemplate<Distributor>>> distributorRegistry = event.getPack().getOrCreateRegistry(DISTRIBUTOR_TOKEN);
                     distributorRegistry.register("NOISE", NoiseDistributorTemplate::new);

common/addons/config-feature/src/main/java/com/dfsek/terra/addons/feature/FeatureAddon.java

@@ -6,6 +6,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 
 @Addon("config-feature")
@@ -18,7 +19,8 @@ public class FeatureAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> event.getPack().registerConfigType(new FeatureConfigType(), "FEATURE", 2));
     }
 }

common/addons/config-flora/src/main/java/com/dfsek/terra/addons/flora/FloraAddon.java

@@ -8,6 +8,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 
 @Addon("config-flora")
@@ -20,7 +21,8 @@ public class FloraAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     event.getPack().registerConfigType(new FloraConfigType(), "FLORA", 2);
                     event.getPack().applyLoader(BlockLayer.class, BlockLayerTemplate::new);

common/addons/config-locators/src/main/java/com/dfsek/terra/addons/feature/locator/LocatorAddon.java

@@ -9,6 +9,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.registry.CheckedRegistry;
 import com.dfsek.terra.api.structure.feature.Locator;
@@ -28,7 +29,8 @@ public class LocatorAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     CheckedRegistry<Supplier<ObjectTemplate<Locator>>> locatorRegistry = event.getPack().getOrCreateRegistry(LOCATOR_TOKEN);
                     locatorRegistry.register("SURFACE", () -> new SurfaceLocatorTemplate(main));

common/addons/config-noise-function/src/main/java/com/dfsek/terra/addons/noise/NoiseAddon.java

@@ -31,6 +31,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.noise.NoiseSampler;
 import com.dfsek.terra.api.registry.CheckedRegistry;
@@ -52,7 +53,8 @@ public class NoiseAddon extends TerraAddon {
     @Override
     public void initialize() {
         plugin.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     CheckedRegistry<Supplier<ObjectTemplate<NoiseSampler>>> noiseRegistry = event.getPack().getOrCreateRegistry(NOISE_SAMPLER_TOKEN);
                     event.getPack()

common/addons/config-ore/src/main/java/com/dfsek/terra/addons/ore/OreAddon.java

@@ -6,6 +6,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.world.generator.GenerationStageProvider;
 
@@ -20,7 +21,8 @@ public class OreAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     event.getPack().registerConfigType(new OreConfigType(), "ORE", 1);
                     event.getPack().getOrCreateRegistry(GenerationStageProvider.class).register("ORE", pack -> new OrePopulator(main));

common/addons/config-palette/src/main/java/com/dfsek/terra/addons/palette/PaletteAddon.java

@@ -8,6 +8,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 
 @Addon("config-palette")
@@ -20,7 +21,8 @@ public class PaletteAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     event.getPack().registerConfigType(new PaletteConfigType(main), "PALETTE", 2);
                     event.getPack().applyLoader(PaletteLayerHolder.class, new PaletteLayerLoader());

common/addons/config-structure/src/main/java/com/dfsek/terra/addons/structure/StructureAddon.java

@@ -6,6 +6,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.structure.configured.ConfiguredStructure;
 
@@ -19,7 +20,8 @@ public class StructureAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> event.getPack().applyLoader(ConfiguredStructure.class, (t, o, l) -> null));
     }
 }

common/addons/generation-stage-feature/src/main/java/com/dfsek/terra/addons/generation/feature/FeatureGenerationAddon.java

@@ -8,6 +8,7 @@ import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.ConfigurationLoadEvent;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.world.biome.TerraBiome;
 import com.dfsek.terra.api.world.generator.GenerationStageProvider;
@@ -22,11 +23,13 @@ public class FeatureGenerationAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> event.getPack().getOrCreateRegistry(GenerationStageProvider.class).register("FEATURE", pack -> new FeatureGenerationStage(main)));
 
         main.getEventManager()
-                .register(ConfigurationLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigurationLoadEvent.class)
                 .then(event -> {
                     if(event.is(TerraBiome.class)) {
                         event.getLoadedObject(TerraBiome.class).getContext().put(event.load(new BiomeFeaturesTemplate()).get());

common/addons/generation-stage-flora/src/main/java/com/dfsek/terra/addons/generation/flora/FloraGenerationAddon.java

@@ -7,6 +7,7 @@ import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.ConfigurationLoadEvent;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.world.biome.TerraBiome;
 import com.dfsek.terra.api.world.generator.GenerationStageProvider;
@@ -22,14 +23,16 @@ public class FloraGenerationAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     event.getPack().applyLoader(FloraLayer.class, FloraLayerLoader::new);
                     event.getPack().getOrCreateRegistry(GenerationStageProvider.class).register("FLORA", pack -> new FloraGenerationStage(main));
                 });
 
         main.getEventManager()
-                .register(ConfigurationLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigurationLoadEvent.class)
                 .then(event -> {
                     if(event.is(TerraBiome.class)) {
                         event.getLoadedObject(TerraBiome.class).getContext().put(event.load(new BiomeFloraTemplate()).get());

common/addons/language-yaml/src/main/java/com/dfsek/terra/addons/yaml/YamlAddon.java

@@ -7,6 +7,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.ConfigurationDiscoveryEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 
 @Addon("language-yaml")
@@ -19,7 +20,8 @@ public class YamlAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigurationDiscoveryEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigurationDiscoveryEvent.class)
                 .then(event -> event.getLoader().open("", ".yml").thenEntries(entries -> entries.forEach(entry -> {
                     main.getDebugLogger().info("Discovered config " + entry.getKey());
                     event.register(entry.getKey(), new YamlConfiguration(entry.getValue(), entry.getKey()));

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/TerraScriptAddon.java

@@ -9,6 +9,7 @@ import com.dfsek.terra.api.addon.annotations.Addon;
 import com.dfsek.terra.api.addon.annotations.Author;
 import com.dfsek.terra.api.addon.annotations.Version;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.injection.annotations.Inject;
 import com.dfsek.terra.api.registry.CheckedRegistry;
 import com.dfsek.terra.api.structure.LootTable;
@@ -27,7 +28,8 @@ public class TerraScriptAddon extends TerraAddon {
     @Override
     public void initialize() {
         main.getEventManager()
-                .register(ConfigPackPreLoadEvent.class)
+                .getHandler(FunctionalEventHandler.class)
+                .register(this, ConfigPackPreLoadEvent.class)
                 .then(event -> {
                     CheckedRegistry<Structure> structureRegistry = event.getPack().getOrCreateRegistry(Structure.class);
                     CheckedRegistry<LootTable> lootRegistry = event.getPack().getOrCreateRegistry(LootTable.class);

common/api/src/main/java/com/dfsek/terra/api/event/EventManager.java

@@ -1,6 +1,5 @@
 package com.dfsek.terra.api.event;
 
-import com.dfsek.terra.api.addon.TerraAddon;
 import com.dfsek.terra.api.event.events.Event;
 import com.dfsek.terra.api.event.functional.EventContext;
 import com.dfsek.terra.api.util.reflection.TypeKey;
@@ -13,21 +12,10 @@ public interface EventManager {
      * Call an event, and return the execution status.
      *
      * @param event Event to pass to all registered EventListeners.
-     * @return False if the event is cancellable and has been cancelled, otherwise true.
      */
-    boolean callEvent(Event event);
+    void callEvent(Event event);
 
-    /**
+    <T extends EventHandler> void registerHandler(Class<T> clazz, T handler);
-     * Register an {@link EventListener} under an {@link TerraAddon}.
-     *
-     * @param addon    Addon to register listener for.
-     * @param listener Listener to register.
-     */
-    void registerListener(TerraAddon addon, EventListener listener);
 
-    <T extends Event> EventContext<T> register(Class<T> clazz);
+    <T extends EventHandler> T getHandler(Class<T> clazz);
-
-    <T extends Event> EventContext<T> register(TypeKey<T> clazz);
-
-    void registerHandler(EventHandler handler);
 }

common/api/src/main/java/com/dfsek/terra/api/event/functional/FunctionalEventHandler.java

@@ -0,0 +1,12 @@
+package com.dfsek.terra.api.event.functional;
+
+import com.dfsek.terra.api.addon.TerraAddon;
+import com.dfsek.terra.api.event.EventHandler;
+import com.dfsek.terra.api.event.events.Event;
+import com.dfsek.terra.api.util.reflection.TypeKey;
+
+public interface FunctionalEventHandler extends EventHandler {
+    <T extends Event> EventContext<T> register(TerraAddon addon, Class<T> clazz);
+
+    <T extends Event> EventContext<T> register(TerraAddon addon, TypeKey<T> clazz);
+}

common/implementation/src/main/java/com/dfsek/terra/event/EventContextImpl.java

@@ -0,0 +1,76 @@
+package com.dfsek.terra.event;
+
+import com.dfsek.terra.api.addon.TerraAddon;
+import com.dfsek.terra.api.event.events.Event;
+import com.dfsek.terra.api.event.events.PackEvent;
+import com.dfsek.terra.api.event.functional.EventContext;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+
+public class EventContextImpl<T extends Event> implements EventContext<T>, Comparable<EventContextImpl<T>> {
+    private final List<Consumer<T>> actions = new ArrayList<>();
+    private int priority;
+    private boolean failThrough = false;
+    private boolean global = false;
+
+    private final TerraAddon addon;
+
+    public EventContextImpl(TerraAddon addon) {
+        this.addon = addon;
+    }
+
+    public void handle(T event) {
+        if(event instanceof PackEvent) {
+
+        }
+        actions.forEach(action -> action.accept(event));
+    }
+
+    @Override
+    public EventContext<T> then(Consumer<T> action) {
+        actions.add(action);
+        return this;
+    }
+
+    @Override
+    public EventContext<T> priority(int priority) {
+        this.priority = priority;
+        return this;
+    }
+
+    @Override
+    public EventContext<T> failThrough() {
+        this.failThrough = true;
+        return this;
+    }
+
+    @Override
+    public EventContext<T> global() {
+        this.global = true;
+        return this;
+    }
+
+    @Override
+    public int compareTo(@NotNull EventContextImpl<T> o) {
+        return this.priority - o.priority;
+    }
+
+    public boolean isGlobal() {
+        return global;
+    }
+
+    public int getPriority() {
+        return priority;
+    }
+
+    public TerraAddon getAddon() {
+        return addon;
+    }
+
+    public boolean isFailThrough() {
+        return failThrough;
+    }
+}

common/implementation/src/main/java/com/dfsek/terra/event/EventManagerImpl.java

@@ -2,110 +2,45 @@ package com.dfsek.terra.event;
 
 import com.dfsek.terra.api.TerraPlugin;
 import com.dfsek.terra.api.addon.TerraAddon;
+import com.dfsek.terra.api.event.EventHandler;
 import com.dfsek.terra.api.event.EventListener;
 import com.dfsek.terra.api.event.EventManager;
-import com.dfsek.terra.api.event.annotations.Global;
-import com.dfsek.terra.api.event.annotations.Priority;
-import com.dfsek.terra.api.event.events.Cancellable;
 import com.dfsek.terra.api.event.events.Event;
-import com.dfsek.terra.api.event.events.PackEvent;
+import com.dfsek.terra.api.event.functional.EventContext;
-import com.dfsek.terra.api.util.reflection.ReflectionUtil;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
+import com.dfsek.terra.api.util.reflection.TypeKey;
 
-import java.io.PrintWriter;
-import java.io.StringWriter;
-import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.lang.reflect.Type;
 import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 public class EventManagerImpl implements EventManager {
-    private final Map<Class<? extends Event>, List<ListenerHolder>> listeners = new HashMap<>();
+    private final Map<Class<?>, EventHandler> handlers = new HashMap<>();
     private final TerraPlugin main;
 
     public EventManagerImpl(TerraPlugin main) {
         this.main = main;
+        registerHandler(FunctionalEventHandler.class, new FunctionalEventHandlerImpl(main)); // default handler
     }
 
     @Override
-    public boolean callEvent(Event event) {
+    public void callEvent(Event event) {
-        listeners.getOrDefault(event.getClass(), Collections.emptyList()).forEach(listenerHolder -> {
+        handlers.values().forEach(handler -> handler.handle(event));
-                    try {
+    }
-                        if(event instanceof PackEvent && !listenerHolder.global) {
+
-                            PackEvent packEvent = (PackEvent) event;
+    @Override
-                            if(packEvent
+    public <T extends EventHandler> void registerHandler(Class<T> clazz, T handler) {
-                                    .getPack()
+        handlers.put(clazz, handler);
-                                    .addons()
-                                    .contains(listenerHolder.addon)) {
-                                listenerHolder.method.invoke(listenerHolder.listener, event);
-                            }
-                        } else {
-                            listenerHolder.method.invoke(listenerHolder.listener, event);
-                        }
-                    } catch(InvocationTargetException e) {
-                        StringWriter writer = new StringWriter();
-                        e.getTargetException().printStackTrace(new PrintWriter(writer));
-                        main.logger().warning("Exception occurred during event handling:");
-                        main.logger().warning(writer.toString());
-                        main.logger().warning("Report this to the maintainers of " + listenerHolder.method.getName());
-                    } catch(Exception e) {
-                        StringWriter writer = new StringWriter();
-                        e.printStackTrace(new PrintWriter(writer));
-                        main.logger().warning("Exception occurred during event handling:");
-                        main.logger().warning(writer.toString());
-                        main.logger().warning("Report this to the maintainers of " + listenerHolder.method.getName());
-                    }
-                }
-        );
-        if(event instanceof Cancellable) return !((Cancellable) event).isCancelled();
-        return true;
     }
 
     @SuppressWarnings("unchecked")
     @Override
-    public void registerListener(TerraAddon addon, EventListener listener) {
+    public <T extends EventHandler> T getHandler(Class<T> clazz) {
-        Class<? extends EventListener> listenerClass = listener.getClass();
+        return (T) handlers.computeIfAbsent(clazz, c -> {
-        Method[] methods = ReflectionUtil.getMethods(listenerClass);
+            throw new IllegalArgumentException("No event handler registered for class " + clazz.getCanonicalName());
-
+        });
-        for(Method method : methods) {
-            if(method.getParameterCount() != 1) continue; // Check that parameter count is only 1.
-            Class<?> eventParam = method.getParameterTypes()[0];
-            if(!Event.class.isAssignableFrom(eventParam)) continue; // Check that parameter is an Event.
-
-            Priority p = method.getAnnotation(Priority.class);
-
-            int priority = p == null ? 0 : p.value();
-
-            method.setAccessible(true);
-
-            List<ListenerHolder> holders = listeners.computeIfAbsent((Class<? extends Event>) eventParam, e -> new ArrayList<>());
-
-            holders.add(new ListenerHolder(method, listener, priority, addon, method.getAnnotation(Global.class) != null));
-
-            holders.sort(Comparator.comparingInt(ListenerHolder::getPriority)); // Sort priorities.
-        }
-    }
-
-    private static final class ListenerHolder {
-        private final Method method;
-        private final EventListener listener;
-        private final int priority;
-        private final TerraAddon addon;
-        private final boolean global;
-
-        private ListenerHolder(Method method, EventListener listener, int priority, TerraAddon addon, boolean global) {
-            this.method = method;
-            this.listener = listener;
-            this.priority = priority;
-            this.addon = addon;
-            this.global = global;
-        }
-
-        public int getPriority() {
-            return priority;
-        }
     }
 }

common/implementation/src/main/java/com/dfsek/terra/event/FunctionalEventHandlerImpl.java

@@ -0,0 +1,65 @@
+package com.dfsek.terra.event;
+
+import com.dfsek.terra.api.TerraPlugin;
+import com.dfsek.terra.api.addon.TerraAddon;
+import com.dfsek.terra.api.event.events.Event;
+import com.dfsek.terra.api.event.events.PackEvent;
+import com.dfsek.terra.api.event.functional.EventContext;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
+import com.dfsek.terra.api.util.reflection.TypeKey;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class FunctionalEventHandlerImpl implements FunctionalEventHandler {
+    private final Map<Type, List<EventContextImpl<?>>> contextMap = new HashMap<>();
+
+    private final TerraPlugin main;
+
+    public FunctionalEventHandlerImpl(TerraPlugin main) {
+        this.main = main;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public void handle(Event event) {
+        contextMap.getOrDefault(event.getClass(), Collections.emptyList()).forEach(context -> {
+            try {
+                if(event instanceof PackEvent) {
+                    if((context.isGlobal() || ((PackEvent) event).getPack().addons().contains(context.getAddon()))) {
+                        ((EventContextImpl<Event>) context).handle(event);
+                    }
+                } else {
+                    ((EventContextImpl<Event>) context).handle(event);
+                }
+            } catch(Exception e) {
+                if(context.isFailThrough()) throw e; // Rethrow if it's fail-through.
+                StringWriter writer = new StringWriter();
+                e.printStackTrace(new PrintWriter(writer));
+                main.logger().warning("Exception occurred during event handling:");
+                main.logger().warning(writer.toString());
+                main.logger().warning("Report this to the maintainers of " + context.getAddon().getName() + ", " + context.getAddon().getAuthor());
+            }
+        });
+    }
+
+    @Override
+    public <T extends Event> EventContext<T> register(TerraAddon addon, Class<T> clazz) {
+        EventContextImpl<T> eventContext = new EventContextImpl<>(addon);
+        contextMap.computeIfAbsent(clazz, c -> new ArrayList<>()).add(eventContext);
+        return eventContext;
+    }
+
+    @Override
+    public <T extends Event> EventContext<T> register(TerraAddon addon, TypeKey<T> clazz) {
+        EventContextImpl<T> eventContext = new EventContextImpl<>(addon);
+        contextMap.computeIfAbsent(clazz.getType(), c -> new ArrayList<>()).add(eventContext);
+        return eventContext;
+    }
+}

platforms/fabric/src/main/java/com/dfsek/terra/fabric/TerraFabricPlugin.java

@@ -17,6 +17,7 @@ import com.dfsek.terra.api.config.PluginConfig;
 import com.dfsek.terra.api.event.EventManager;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPostLoadEvent;
 import com.dfsek.terra.api.event.events.config.pack.ConfigPackPreLoadEvent;
+import com.dfsek.terra.api.event.functional.FunctionalEventHandler;
 import com.dfsek.terra.api.handle.ItemHandle;
 import com.dfsek.terra.api.handle.WorldHandle;
 import com.dfsek.terra.api.lang.Language;
@@ -289,7 +290,8 @@ public class TerraFabricPlugin implements TerraPlugin, ModInitializer {
         @Override
         public void initialize() {
             eventManager
-                    .register(ConfigPackPreLoadEvent.class)
+                    .getHandler(FunctionalEventHandler.class)
+                    .register(this, ConfigPackPreLoadEvent.class)
                     .then(event -> {
                         PreLoadCompatibilityOptions template = new PreLoadCompatibilityOptions();
                         try {
@@ -314,7 +316,8 @@ public class TerraFabricPlugin implements TerraPlugin, ModInitializer {
                     .global();
 
             eventManager
-                    .register(ConfigPackPostLoadEvent.class)
+                    .getHandler(FunctionalEventHandler.class)
+                    .register(this, ConfigPackPostLoadEvent.class)
                     .then(event -> {
                         PostLoadCompatibilityOptions template = new PostLoadCompatibilityOptions();
 
@@ -330,7 +333,8 @@ public class TerraFabricPlugin implements TerraPlugin, ModInitializer {
                     .global();
 
             eventManager
-                    .register(BiomeRegistrationEvent.class)
+                    .getHandler(FunctionalEventHandler.class)
+                    .register(this, BiomeRegistrationEvent.class)
                     .then(event -> {
                         logger.info("Registering biomes...");
                         Registry<Biome> biomeRegistry = event.getRegistryManager().get(Registry.BIOME_KEY);
@@ -340,7 +344,8 @@ public class TerraFabricPlugin implements TerraPlugin, ModInitializer {
                     .global();
 
             eventManager
-                    .register(GameInitializationEvent.class)
+                    .getHandler(FunctionalEventHandler.class)
+                    .register(this, GameInitializationEvent.class)
                     .then(event -> {
                         TerraFabricPlugin main = TerraFabricPlugin.getInstance();
                         main.logger().info("Loading config packs...");