Counter doesn't count anything. Added ability to collect the messages

from the MessageData that it receives.

data-bus/src/main/java/com/iluwatar/databus/App.java

@@ -26,7 +26,7 @@ package com.iluwatar.databus;
 import com.iluwatar.databus.data.MessageData;
 import com.iluwatar.databus.data.StartingData;
 import com.iluwatar.databus.data.StoppingData;
-import com.iluwatar.databus.members.CounterMember;
+import com.iluwatar.databus.members.MessageCollectorMember;
 import com.iluwatar.databus.members.StatusMember;
 
 import java.time.LocalDateTime;
@@ -44,8 +44,8 @@ class App {
     final DataBus bus = DataBus.getInstance();
     bus.subscribe(new StatusMember(1));
     bus.subscribe(new StatusMember(2));
-    final CounterMember foo = new CounterMember("Foo");
-    final CounterMember bar = new CounterMember("Bar");
+    final MessageCollectorMember foo = new MessageCollectorMember("Foo");
+    final MessageCollectorMember bar = new MessageCollectorMember("Bar");
     bus.subscribe(foo);
     bus.publish(StartingData.of(LocalDateTime.now()));
     bus.publish(MessageData.of("Only Foo should see this"));

data-bus/src/main/java/com/iluwatar/databus/members/MessageCollectorMember.java

@@ -27,20 +27,25 @@ import com.iluwatar.databus.DataType;
 import com.iluwatar.databus.Member;
 import com.iluwatar.databus.data.MessageData;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.logging.Logger;
 
 /**
- * Receiver of Data-Bus events.
+ * Receiver of Data-Bus events that collects the messages from each {@link MessageData}.
  *
  * @author Paul Campbell (pcampbell@kemitix.net)
  */
-public class CounterMember implements Member {
+public class MessageCollectorMember implements Member {
 
-  private static final Logger LOGGER = Logger.getLogger(CounterMember.class.getName());
+  private static final Logger LOGGER = Logger.getLogger(MessageCollectorMember.class.getName());
 
   private final String name;
 
-  public CounterMember(String name) {
+  private List<String> messages = new ArrayList<>();
+
+  public MessageCollectorMember(String name) {
     this.name = name;
   }
 
@@ -53,5 +58,10 @@ public class CounterMember implements Member {
 
   private void handleEvent(MessageData data) {
     LOGGER.info(String.format("%s sees message %s", name, data.getMessage()));
+    messages.add(data.getMessage());
+  }
+
+  public List<String> getMessages() {
+    return Collections.unmodifiableList(messages);
   }
 }