[JAVA-15377] Update code for Graphql SPQR article

graphql-modules/graphql-spqr/src/main/java/com/baeldung/spqr/BookService.java

@@ -1,51 +1,53 @@
 package com.baeldung.spqr;
 
-import io.leangen.graphql.annotations.GraphQLArgument;
-import io.leangen.graphql.annotations.GraphQLMutation;
-import io.leangen.graphql.annotations.GraphQLQuery;
-import io.leangen.graphql.spqr.spring.annotations.GraphQLApi;
 import org.springframework.stereotype.Service;
 
+import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 @Service
-@GraphQLApi
 public class BookService implements IBookService {
 
-    Set<Book> books = new HashSet<>();
+    private static final Set<Book> BOOKS_DATA = initializeData();
 
-    @GraphQLQuery(name = "getBookWithTitle")
-    public Book getBookWithTitle(@GraphQLArgument(name = "title") String title) {
-        return books.stream()
-            .filter(book -> book.getTitle()
-                .equals(title))
+    @Override
+    public Book getBookWithTitle(String title) {
+        return BOOKS_DATA.stream()
+            .filter(book -> book.getTitle().equals(title))
             .findFirst()
             .orElse(null);
     }
 
-    @GraphQLQuery(name = "getAllBooks", description = "Get all books")
+    @Override
     public List<Book> getAllBooks() {
-        return books.stream().collect(Collectors.toList());
+        return new ArrayList<>(BOOKS_DATA);
     }
 
-    @GraphQLMutation(name = "addBook")
-    public Book addBook(@GraphQLArgument(name = "newBook") Book book) {
-        books.add(book);
+    @Override
+    public Book addBook(Book book) {
+        BOOKS_DATA.add(book);
         return book;
     }
 
-    @GraphQLMutation(name = "updateBook")
-    public Book updateBook(@GraphQLArgument(name = "modifiedBook") Book book) {
-        books.remove(book);
-        books.add(book);
+    @Override
+    public Book updateBook(Book book) {
+        BOOKS_DATA.removeIf(b -> Objects.equals(b.getId(), book.getId()));
+        BOOKS_DATA.add(book);
         return book;
     }
 
-    @GraphQLMutation(name = "deleteBook")
-    public boolean deleteBook(@GraphQLArgument(name = "book") Book book) {
-        return books.remove(book);
+    @Override
+    public boolean deleteBook(Book book) {
+        return BOOKS_DATA.remove(book);
     }
-}
+
+    private static Set<Book> initializeData() {
+        Book book = new Book(1, "J.R.R. Tolkien", "The Lord of the Rings");
+        Set<Book> books = new HashSet<>();
+        books.add(book);
+        return books;
+    }
+}