Bael 3653: Adding Pageable Support (#8766)

* Removed the commented code

* Upgrading the Spring Doc Version

* Adding the Pageable Example

In order to use `Pageable`, I had to add `spring-data-jpa` dep and H2. Also, the Spring doc version was quite outdated, so an upgrade for that, too.

* Adding the Pageable Example

In order to use `Pageable`, I had to add `spring-data-jpa` dep and H2. Also, the Spring doc version was quite outdated, so an upgrade for that, too.

spring-boot-modules/spring-boot-springdoc/src/main/java/com/baeldung/springdoc/controller/BookController.java

@@ -6,6 +6,8 @@ import javax.validation.Valid;
 import javax.validation.constraints.NotNull;
 
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.http.HttpStatus;
 import org.springframework.web.bind.annotation.DeleteMapping;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -41,6 +43,11 @@ public class BookController {
         return repository.getBooks();
     }
 
+    @GetMapping("/filter")
+    public Page<Book> filterBooks(Pageable pageable) {
+        return repository.getBooks(pageable);
+    }
+
     @PutMapping("/{id}")
     @ResponseStatus(HttpStatus.OK)
     public Book updateBook(@PathVariable("id") final String id, @RequestBody final Book book) {

spring-boot-modules/spring-boot-springdoc/src/main/java/com/baeldung/springdoc/repository/BookRepository.java

@@ -1,13 +1,14 @@
 package com.baeldung.springdoc.repository;
 
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
-
+import com.baeldung.springdoc.model.Book;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageImpl;
+import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Repository;
 
-import com.baeldung.springdoc.model.Book;
+import java.util.*;
+
+import static java.util.stream.Collectors.toList;
 
 @Repository
 public class BookRepository {
@@ -25,4 +26,11 @@ public class BookRepository {
     public Collection<Book> getBooks() {
         return books.values();
     }
+
+    public Page<Book> getBooks(Pageable pageable) {
+        int toSkip = pageable.getPageSize() * pageable.getPageNumber();
+        List<Book> result = books.values().stream().skip(toSkip).limit(pageable.getPageSize()).collect(toList());
+
+        return new PageImpl<>(result, pageable, books.size());
+    }
 }