refactor: A `ChatRoom` does not have to remember its shard any more

[demos/kafka/chat] / src / main / java / de / juplo / kafka / chat / backend / domain / ChatRoom.java

diff --git a/src/main/java/de/juplo/kafka/chat/backend/domain/ChatRoom.java b/src/main/java/de/juplo/kafka/chat/backend/domain/ChatRoom.java
index 35d0c3d..1c21fb9 100644 (file)
--- a/src/main/java/de/juplo/kafka/chat/backend/domain/ChatRoom.java
+++ b/src/main/java/de/juplo/kafka/chat/backend/domain/ChatRoom.java
@@ -11,6 +11,8 @@ import reactor.core.publisher.Sinks;
 import java.time.Clock;
 import java.time.LocalDateTime;
 import java.util.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 
 @Slf4j
@@ -18,6 +20,7 @@ import java.util.*;
 @ToString(of = { "id", "name" })
 public class ChatRoom
 {
+  public final static Pattern VALID_USER = Pattern.compile("^[a-z0-9-]{2,}$");
   @Getter
   private final UUID id;
   @Getter
@@ -27,6 +30,7 @@ public class ChatRoom
   private final int bufferSize;
   private Sinks.Many<Message> sink;
 
+
   public ChatRoom(
       UUID id,
       String name,
@@ -39,6 +43,9 @@ public class ChatRoom
     this.clock = clock;
     this.service = service;
     this.bufferSize = bufferSize;
+    // @RequiredArgsConstructor unfortunately not possible, because
+    // the `bufferSize` is not set, if `createSink()` is called
+    // from the variable declaration!
     this.sink = createSink();
   }
 
@@ -48,6 +55,10 @@ public class ChatRoom
       String user,
       String text)
   {
+    Matcher matcher = VALID_USER.matcher(user);
+    if (!matcher.matches())
+      throw new InvalidUsernameException(user);
+
     Message.MessageKey key = Message.MessageKey.of(user, id);
     return service
         .getMessage(key)