Make the clientSide/serverSide builder options additative.

ProtocolLib/src/main/java/com/comphenix/protocol/events/ConnectionSide.java

@@ -45,4 +45,30 @@ public enum ConnectionSide {
 	public boolean isForServer() {
 		return this == SERVER_SIDE || this == BOTH;
 	}
+	
+	/**
+	 * If both connection sides are present, return {@link #BOTH} - otherwise, return the one valud connection side.
+	 * <p>
+	 * NULL is not a valid connection side.
+	 * @param a - the first connection side.
+	 * @param b - the second connection side.
+	 * @return BOTH or the one valid side, or NULL.
+	 */
+	public static ConnectionSide add(ConnectionSide a, ConnectionSide b) {
+		if (a == null)
+			return b;
+		if (b == null)
+			return a;
+		
+		// Now merge them together
+		boolean client = a.isForClient() || b.isForClient();
+		boolean server = a.isForServer() || b.isForServer();
+		
+		if (client && server)
+			return BOTH;
+		else if (client)
+			return CLIENT_SIDE;
+		else
+			return SERVER_SIDE;
+	}
 }

ProtocolLib/src/main/java/com/comphenix/protocol/events/PacketAdapter.java

@@ -301,19 +301,19 @@ public abstract class PacketAdapter implements PacketListener {
 		}
 		
 		/**
-		 * Set this adapter to look for client-side packets only. 
+		 * Set this adapter to also look for client-side packets. 
 		 * @return This builder, for chaining.
 		 */
 		public AdapterParameteters clientSide() {
-			return connectionSide(ConnectionSide.CLIENT_SIDE);
+			return connectionSide(ConnectionSide.add(connectionSide, ConnectionSide.CLIENT_SIDE));
 		}
 		
 		/**
-		 * Set this adapter to look for client-side packets only. 
+		 * Set this adapter to also look for client-side packets. 
 		 * @return This builder, for chaining.
 		 */
 		public AdapterParameteters serverSide() {
-			return connectionSide(ConnectionSide.SERVER_SIDE);
+			return connectionSide(ConnectionSide.add(connectionSide, ConnectionSide.SERVER_SIDE));
 		}
 		
 		/**