Added book controller

src/main/java/com/fnecan/study/bookapi/api/BookController.java

@@ -3,6 +3,7 @@ package com.fnecan.study.bookapi.api;
 import com.fnecan.study.bookapi.service.BookService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestHeader;
@@ -32,4 +33,15 @@ public class BookController {
                 bookService.getBookDetails(userId, bookId)
         );
     }
+
+    @DeleteMapping("/{bookId}")
+    public ResponseEntity removeBook(
+            @RequestHeader("userId") String userId,
+            @PathVariable("bookId") String bookId
+    ){
+        return ResponseEntity.ok(
+                bookService.removeBook(userId, bookId)
+        );
+    }
+
 }

src/main/java/com/fnecan/study/bookapi/repository/BookRepository.java

@@ -6,7 +6,7 @@ import org.springframework.data.mongodb.repository.MongoRepository;
 import java.util.List;
 import java.util.Optional;
 
-public interface BookRepository extends MongoRepository<BookDocument, String> {
+public interface BookRepository extends MongoRepository<BookDocument, String>, BookRepositoryCustom {
     List<BookDocument> findByUserId(String userId);
     Optional<BookDocument> findByUserIdAndId(String userId, String bookId);
 }

src/main/java/com/fnecan/study/bookapi/repository/BookRepositoryCustom.java

@@ -0,0 +1,9 @@
+package com.fnecan.study.bookapi.repository;
+
+import com.fnecan.study.bookapi.model.BookDocument;
+
+import java.util.Optional;
+
+public interface BookRepositoryCustom {
+    Optional<BookDocument> removeBook(String userId, String bookId);
+}

src/main/java/com/fnecan/study/bookapi/repository/BookRepositoryCustomImplementation.java

@@ -0,0 +1,23 @@
+package com.fnecan.study.bookapi.repository;
+
+import com.fnecan.study.bookapi.model.BookDocument;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.mongodb.core.MongoTemplate;
+import org.springframework.data.mongodb.core.query.Criteria;
+import org.springframework.data.mongodb.core.query.Query;
+
+import java.util.Optional;
+
+public class BookRepositoryCustomImplementation implements BookRepositoryCustom {
+
+    @Autowired
+    MongoTemplate mongoTemplate;
+
+    @Override
+    public Optional<BookDocument> removeBook(String userId, String bookId) {
+        return Optional.ofNullable(mongoTemplate.findAndRemove(
+                Query.query(
+                        Criteria.where("userId").is(userId).and("id").is(bookId)
+                ), BookDocument.class));
+    }
+}

src/main/java/com/fnecan/study/bookapi/service/BookService.java

@@ -21,4 +21,8 @@ public class BookService {
     public Optional<BookDocument> getBookDetails(String userId, String bookId) {
         return bookRepository.findByUserIdAndId(userId, bookId);
     }
+
+    public Optional<BookDocument> removeBook(String userId, String bookId) {
+        return bookRepository.removeBook(userId, bookId);
+    }
 }