improvement: Change to using functional interfaces for clientbound packet handling (#29)

Author: nextdayy

src/main/java/net/hypixel/modapi/HypixelModAPI.java

@@ -28,7 +28,7 @@ public static HypixelModAPI getInstance() {
     }
 
     private final PacketRegistry registry = new PacketRegistry();
-    private final List<ClientboundPacketHandler> handlers = new CopyOnWriteArrayList<>();
+    private final Map<Class<? extends ClientboundHypixelPacket>, Collection<ClientboundPacketHandler<?>>> handlers = new ConcurrentHashMap<>();
     private final Set<String> subscribedEvents = ConcurrentHashMap.newKeySet();
     private Set<String> lastSubscribedEvents = Collections.emptySet();
     private Predicate<HypixelPacket> packetSender = null;
@@ -71,20 +71,16 @@ private void registerEventPackets() {
     }
 
     private void registerDefaultHandler() {
-        registerHandler(new ClientboundPacketHandler() {
-            @Override
-            public void onHelloEvent(ClientboundHelloPacket packet) {
-                sendRegisterPacket(true);
-            }
-        });
+        registerHandler(ClientboundHelloPacket.class, p -> sendRegisterPacket(true));
     }
 
     public PacketRegistry getRegistry() {
         return registry;
     }
 
-    public void registerHandler(ClientboundPacketHandler handler) {
-        handlers.add(handler);
+    public <T extends ClientboundHypixelPacket> void registerHandler(Class<T> packetClass, ClientboundPacketHandler<T> handler) {
+        if (packetClass == null || handler == null) return;
+        handlers.computeIfAbsent(packetClass, cls -> new CopyOnWriteArrayList<>()).add(handler);
     }
 
     public void subscribeToEventPacket(Class<? extends EventPacket> packet) {
@@ -134,9 +130,14 @@ public void handle(String identifier, PacketSerializer serializer) {
         handle(packet);
     }
 
+    @SuppressWarnings("unchecked")
     public void handle(ClientboundHypixelPacket packet) {
-        for (ClientboundPacketHandler handler : handlers) {
-            packet.handle(handler);
+        Collection<ClientboundPacketHandler<?>> typedHandlers = handlers.get(packet.getClass());
+        // nothing registered for this packet.
+        if (typedHandlers == null) return;
+        for (ClientboundPacketHandler<?> handler : typedHandlers) {
+            // this cast is safe as we ensure its type when it is added to the handlers list in the first place.
+            ((ClientboundPacketHandler<ClientboundHypixelPacket>) handler).handle(packet);
         }
     }
 

src/main/java/net/hypixel/modapi/handler/ClientboundPacketHandler.java

@@ -1,25 +1,8 @@
 package net.hypixel.modapi.handler;
 
-import net.hypixel.modapi.packet.impl.clientbound.ClientboundHelloPacket;
-import net.hypixel.modapi.packet.impl.clientbound.ClientboundPartyInfoPacket;
-import net.hypixel.modapi.packet.impl.clientbound.ClientboundPingPacket;
-import net.hypixel.modapi.packet.impl.clientbound.ClientboundPlayerInfoPacket;
-import net.hypixel.modapi.packet.impl.clientbound.event.ClientboundLocationPacket;
+import net.hypixel.modapi.packet.ClientboundHypixelPacket;
 
-public interface ClientboundPacketHandler {
-
-    default void onHelloEvent(ClientboundHelloPacket packet) {
-    }
-
-    default void onPingPacket(ClientboundPingPacket packet) {
-    }
-
-    default void onPartyInfoPacket(ClientboundPartyInfoPacket packet) {
-    }
-
-    default void onPlayerInfoPacket(ClientboundPlayerInfoPacket packet) {
-    }
-
-    default void onLocationEvent(ClientboundLocationPacket packet) {
-    }
+@FunctionalInterface
+public interface ClientboundPacketHandler<T extends ClientboundHypixelPacket> {
+    void handle(T packet);
 }

src/main/java/net/hypixel/modapi/packet/ClientboundHypixelPacket.java

@@ -1,9 +1,4 @@
 package net.hypixel.modapi.packet;
 
-import net.hypixel.modapi.handler.ClientboundPacketHandler;
-
 public interface ClientboundHypixelPacket extends HypixelPacket {
-
-    void handle(ClientboundPacketHandler handler);
-
 }

src/main/java/net/hypixel/modapi/packet/impl/clientbound/ClientboundHelloPacket.java

@@ -1,8 +1,6 @@
 package net.hypixel.modapi.packet.impl.clientbound;
 
 import net.hypixel.data.region.Environment;
-import net.hypixel.modapi.annotation.Experimental;
-import net.hypixel.modapi.handler.ClientboundPacketHandler;
 import net.hypixel.modapi.packet.ClientboundHypixelPacket;
 import net.hypixel.modapi.serializer.PacketSerializer;
 
@@ -24,11 +22,6 @@ public ClientboundHelloPacket(PacketSerializer serializer) {
         serializer.discardRemaining();
     }
 
-    @Override
-    public void handle(ClientboundPacketHandler handler) {
-        handler.onHelloEvent(this);
-    }
-
     @Override
     public void write(PacketSerializer serializer) {
         serializer.writeVarInt(environment.getId());

src/main/java/net/hypixel/modapi/packet/impl/clientbound/ClientboundPartyInfoPacket.java

@@ -1,6 +1,5 @@
 package net.hypixel.modapi.packet.impl.clientbound;
 
-import net.hypixel.modapi.handler.ClientboundPacketHandler;
 import net.hypixel.modapi.serializer.PacketSerializer;
 
 import java.util.*;
@@ -84,11 +83,6 @@ protected int getLatestVersion() {
         return CURRENT_VERSION;
     }
 
-    @Override
-    public void handle(ClientboundPacketHandler handler) {
-        handler.onPartyInfoPacket(this);
-    }
-
     public boolean isInParty() {
         return inParty;
     }

src/main/java/net/hypixel/modapi/packet/impl/clientbound/ClientboundPingPacket.java

@@ -1,8 +1,5 @@
 package net.hypixel.modapi.packet.impl.clientbound;
 
-import net.hypixel.modapi.handler.ClientboundPacketHandler;
-import net.hypixel.modapi.packet.ClientboundHypixelPacket;
-import net.hypixel.modapi.packet.impl.VersionedPacket;
 import net.hypixel.modapi.serializer.PacketSerializer;
 
 public class ClientboundPingPacket extends ClientboundVersionedPacket {
@@ -40,11 +37,6 @@ protected int getLatestVersion() {
         return CURRENT_VERSION;
     }
 
-    @Override
-    public void handle(ClientboundPacketHandler handler) {
-        handler.onPingPacket(this);
-    }
-
     public String getResponse() {
         return response;
     }

src/main/java/net/hypixel/modapi/packet/impl/clientbound/ClientboundPlayerInfoPacket.java

@@ -3,9 +3,6 @@
 import net.hypixel.data.rank.MonthlyPackageRank;
 import net.hypixel.data.rank.PackageRank;
 import net.hypixel.data.rank.PlayerRank;
-import net.hypixel.modapi.handler.ClientboundPacketHandler;
-import net.hypixel.modapi.packet.ClientboundHypixelPacket;
-import net.hypixel.modapi.packet.impl.VersionedPacket;
 import net.hypixel.modapi.serializer.PacketSerializer;
 import org.jetbrains.annotations.Nullable;
 
@@ -59,11 +56,6 @@ protected int getLatestVersion() {
         return CURRENT_VERSION;
     }
 
-    @Override
-    public void handle(ClientboundPacketHandler handler) {
-        handler.onPlayerInfoPacket(this);
-    }
-
     public PlayerRank getPlayerRank() {
         return playerRank;
     }

src/main/java/net/hypixel/modapi/packet/impl/clientbound/event/ClientboundLocationPacket.java

@@ -1,7 +1,6 @@
 package net.hypixel.modapi.packet.impl.clientbound.event;
 
 import net.hypixel.data.type.ServerType;
-import net.hypixel.modapi.handler.ClientboundPacketHandler;
 import net.hypixel.modapi.packet.EventPacket;
 import net.hypixel.modapi.packet.impl.clientbound.ClientboundVersionedPacket;
 import net.hypixel.modapi.serializer.PacketSerializer;
@@ -64,11 +63,6 @@ protected int getLatestVersion() {
         return CURRENT_VERSION;
     }
 
-    @Override
-    public void handle(ClientboundPacketHandler handler) {
-        handler.onLocationEvent(this);
-    }
-
     public String getServerName() {
         return serverName;
     }