add hashCode and equals to Author and Book DTOs

cqrs/src/main/java/com/iluwatar/cqrs/dto/Author.java

@@ -1,5 +1,7 @@
 package com.iluwatar.cqrs.dto;
 
+import java.util.Objects;
+
 /**
  * 
  * This is a DTO (Data Transfer Object) author, contains only useful information to be returned
@@ -48,4 +50,22 @@ public class Author {
     return "AuthorDTO [name=" + name + ", email=" + email + ", username=" + username + "]";
   }
 
+  @Override
+  public int hashCode() {
+    return Objects.hash(username, name, email);
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj) {
+      return true;
+    }
+    if (!(obj instanceof Author)) {
+      return false;
+    }
+    Author other = (Author) obj;
+    return username.equals(other.getUsername()) && email.equals(other.getEmail()) && name.equals(other.getName());
+
+  }
+
 }

cqrs/src/main/java/com/iluwatar/cqrs/dto/Book.java

@@ -1,5 +1,7 @@
 package com.iluwatar.cqrs.dto;
 
+import java.util.Objects;
+
 /**
  * 
  * This is a DTO (Data Transfer Object) book, contains only useful information to be returned
@@ -40,4 +42,21 @@ public class Book {
     return "BookDTO [title=" + title + ", price=" + price + "]";
   }
 
+  @Override
+  public int hashCode() {
+    return Objects.hash(title, price);
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj) {
+      return true;
+    }
+    if (!(obj instanceof Book)) {
+      return false;
+    }
+    Book book = (Book) obj;
+    return title.equals(book.getTitle()) && price == book.getPrice();
+  }
+
 }