BAEL-2435 Update commands and events

-Change TargetAggregateIdentifier import statement to the new location
-Add equals/hashcode as best practice for commands and events
-Add description
-Change parent to parent-boot-2 to leverage a spring boot start up
approach

axon/src/main/java/com/baeldung/axon/commands/CreateMessageCommand.java

@@ -1,7 +1,8 @@
 package com.baeldung.axon.commands;
 
+import java.util.Objects;
 
-import org.axonframework.commandhandling.TargetAggregateIdentifier;
+import org.axonframework.modelling.command.TargetAggregateIdentifier;
 
 public class CreateMessageCommand {
 
@@ -21,4 +22,21 @@ public class CreateMessageCommand {
     public String getText() {
         return text;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        CreateMessageCommand that = (CreateMessageCommand) o;
+        return Objects.equals(id, that.id) && Objects.equals(text, that.text);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, text);
+    }
 }

axon/src/main/java/com/baeldung/axon/commands/MarkReadMessageCommand.java

@@ -1,7 +1,8 @@
 package com.baeldung.axon.commands;
 
+import java.util.Objects;
 
-import org.axonframework.commandhandling.TargetAggregateIdentifier;
+import org.axonframework.modelling.command.TargetAggregateIdentifier;
 
 public class MarkReadMessageCommand {
 
@@ -15,4 +16,21 @@ public class MarkReadMessageCommand {
     public String getId() {
         return id;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        MarkReadMessageCommand that = (MarkReadMessageCommand) o;
+        return Objects.equals(id, that.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
 }

axon/src/main/java/com/baeldung/axon/events/MessageCreatedEvent.java

@@ -1,5 +1,7 @@
 package com.baeldung.axon.events;
 
+import java.util.Objects;
+
 public class MessageCreatedEvent {
 
     private final String id;
@@ -17,4 +19,21 @@ public class MessageCreatedEvent {
     public String getText() {
         return text;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        MessageCreatedEvent that = (MessageCreatedEvent) o;
+        return Objects.equals(id, that.id) && Objects.equals(text, that.text);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, text);
+    }
 }

axon/src/main/java/com/baeldung/axon/events/MessageReadEvent.java

@@ -1,5 +1,7 @@
 package com.baeldung.axon.events;
 
+import java.util.Objects;
+
 public class MessageReadEvent {
 
     private final String id;
@@ -11,4 +13,21 @@ public class MessageReadEvent {
     public String getId() {
         return id;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        MessageReadEvent that = (MessageReadEvent) o;
+        return Objects.equals(id, that.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
 }