Scroll API Implementation (#14435)

Co-authored-by: technoddy <mail.technoddy@gmail.com>

persistence-modules/spring-boot-persistence-4/pom.xml

@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.boot.persistence</groupId>
+    <artifactId>spring-boot-persistence-4</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>spring-boot-persistence-4</name>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.junit</groupId>
+                <artifactId>junit-bom</artifactId>
+                <version>${junit-jupiter.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+                <version>${spring.boot.dependencies}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <spring.boot.dependencies>3.1.0</spring.boot.dependencies>
+        <junit-jupiter.version>5.9.3</junit-jupiter.version>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+    </properties>
+
+</project>

persistence-modules/spring-boot-persistence-4/src/main/java/com/baeldung/scrollapi/ScrollAPIApplication.java

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+package com.baeldung.scrollapi;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ScrollAPIApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(ScrollAPIApplication.class, args);
+    }
+}

persistence-modules/spring-boot-persistence-4/src/main/java/com/baeldung/scrollapi/entity/BookReview.java

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+package com.baeldung.scrollapi.entity;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(name = "BOOK_REVIEWS")
+public class BookReview {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "book_reviews_reviews_id_seq")
+    @SequenceGenerator(name = "book_reviews_reviews_id_seq", sequenceName = "book_reviews_reviews_id_seq", allocationSize = 1)
+    private Long reviewsId;
+    private String userId;
+    private String isbn;
+    private String bookRating;
+
+    public Long getReviewsId() {
+        return reviewsId;
+    }
+
+    public void setReviewsId(Long reviewsId) {
+        this.reviewsId = reviewsId;
+    }
+
+    public String getUserId() {
+        return userId;
+    }
+
+    public void setUserId(String userId) {
+        this.userId = userId;
+    }
+
+    public String getIsbn() {
+        return isbn;
+    }
+
+    public void setIsbn(String isbn) {
+        this.isbn = isbn;
+    }
+
+    public String getBookRating() {
+        return bookRating;
+    }
+
+    public void setBookRating(String bookRating) {
+        this.bookRating = bookRating;
+    }
+
+    @Override
+    public String toString() {
+        return "BookReview{" + "reviewsId=" + reviewsId + ", userId='" + userId + '\'' + ", isbn='" + isbn + '\'' + ", bookRating='" + bookRating + '\'' + '}';
+    }
+}

persistence-modules/spring-boot-persistence-4/src/main/java/com/baeldung/scrollapi/repository/BookRepository.java

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+package com.baeldung.scrollapi.repository;
+
+import org.springframework.data.domain.KeysetScrollPosition;
+import org.springframework.data.domain.OffsetScrollPosition;
+import org.springframework.data.domain.Window;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.repository.Repository;
+
+import com.baeldung.scrollapi.entity.BookReview;
+
+public interface BookRepository extends JpaRepository<BookReview, Long> {
+
+    Window<BookReview> findFirst5ByBookRating(String bookRating, OffsetScrollPosition position);
+
+    Window<BookReview> findFirst5ByBookRating(String bookRating, KeysetScrollPosition position);
+}

persistence-modules/spring-boot-persistence-4/src/main/java/com/baeldung/scrollapi/service/BookLogic.java

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+package com.baeldung.scrollapi.service;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.KeysetScrollPosition;
+import org.springframework.data.domain.OffsetScrollPosition;
+import org.springframework.data.domain.ScrollPosition;
+import org.springframework.data.domain.Window;
+import org.springframework.data.support.WindowIterator;
+import org.springframework.stereotype.Service;
+
+import com.baeldung.scrollapi.entity.BookReview;
+import com.baeldung.scrollapi.repository.BookRepository;
+
+@Service
+public class BookLogic {
+
+    @Autowired
+    private BookRepository bookRepository;
+
+    public List<BookReview> getBooksUsingOffset(String rating) {
+        OffsetScrollPosition offset = ScrollPosition.offset();
+
+        Window<BookReview> bookReviews = bookRepository.findFirst5ByBookRating(rating, offset);
+        List<BookReview> bookReviewsResult = new ArrayList<>();
+        do {
+            bookReviews.forEach(bookReviewsResult::add);
+            bookReviews = bookRepository.findFirst5ByBookRating(rating, (OffsetScrollPosition) bookReviews.positionAt(bookReviews.size() - 1));
+        } while (!bookReviews.isEmpty() && bookReviews.hasNext());
+
+        return bookReviewsResult;
+    }
+
+    public List<BookReview> getBooksUsingOffSetFilteringAndWindowIterator(String rating) {
+        WindowIterator<BookReview> bookReviews = WindowIterator.of(position -> bookRepository.findFirst5ByBookRating("3.5", (OffsetScrollPosition) position))
+            .startingAt(ScrollPosition.offset());
+        List<BookReview> bookReviewsResult = new ArrayList<>();
+
+        bookReviews.forEachRemaining(bookReviewsResult::add);
+        return bookReviewsResult;
+    }
+
+    public List<BookReview> getBooksUsingKeySetFiltering(String rating) {
+        WindowIterator<BookReview> bookReviews = WindowIterator.of(position -> bookRepository.findFirst5ByBookRating(rating, (KeysetScrollPosition) position))
+            .startingAt(ScrollPosition.keyset());
+        List<BookReview> bookReviewsResult = new ArrayList<>();
+
+        bookReviews.forEachRemaining(bookReviewsResult::add);
+        return bookReviewsResult;
+    }
+}

persistence-modules/spring-boot-persistence-4/src/main/resources/application.yml

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+
+logging.level.org.hibernate:
+  SQL: DEBUG
+  type.descriptor.sql.BasicBinder: TRACE

persistence-modules/spring-boot-persistence-4/src/test/java/com/baeldung/boot/scrollapi/service/BookLogicUnitTest.java

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+package com.baeldung.boot.scrollapi.service;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+import java.util.List;
+import java.util.UUID;
+import java.util.stream.IntStream;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import com.baeldung.scrollapi.ScrollAPIApplication;
+import com.baeldung.scrollapi.entity.BookReview;
+import com.baeldung.scrollapi.repository.BookRepository;
+import com.baeldung.scrollapi.service.BookLogic;
+
+@SpringBootTest(classes = ScrollAPIApplication.class)
+class BookLogicUnitTest {
+
+    @Autowired
+    private BookRepository bookRepository;
+
+    @Autowired
+    private BookLogic bookLogic;
+
+    @BeforeEach
+    public void beforeEach() {
+        IntStream.rangeClosed(1, 5)
+            .forEach(i -> insertBookReview());
+    }
+
+    @AfterEach
+    public void afterEach() {
+        bookRepository.deleteAll();
+    }
+
+    @Test
+    public void givenBookReviewInTable_whenGetBooksUsingOffset_returnsBookReviews() {
+        List<BookReview> bookReviews = bookLogic.getBooksUsingOffset("3.5");
+        assertThat(bookReviews.size()).isEqualTo(5);
+    }
+
+    @Test
+    public void givenBookReviewInTable_whenGetBooksUsingOffSetFilteringAndWindowIterator_returnsBookReviews() {
+        List<BookReview> bookReviews = bookLogic.getBooksUsingOffSetFilteringAndWindowIterator("3.5");
+        assertThat(bookReviews.size()).isEqualTo(5);
+    }
+
+    @Test
+    public void givenBookReviewInTable_whenGetBooksUsingKeySetFiltering_returnsBookReviews() {
+        List<BookReview> bookReviews = bookLogic.getBooksUsingKeySetFiltering("3.5");
+        assertThat(bookReviews.size()).isEqualTo(5);
+    }
+
+    private void insertBookReview() {
+        BookReview bookReview = getBookReview();
+        bookRepository.save(bookReview);
+    }
+
+    private static BookReview getBookReview() {
+        BookReview bookReview = new BookReview();
+        String seed = UUID.randomUUID()
+            .toString();
+        bookReview.setIsbn("isbn" + seed);
+        bookReview.setBookRating("3.5");
+        bookReview.setUserId(seed);
+
+        return bookReview;
+    }
+}

persistence-modules/spring-boot-persistence-4/src/test/resources/application.properties

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+# spring.datasource.x
+spring.datasource.driver-class-name=org.h2.Driver
+spring.datasource.url=jdbc:h2:mem:db;DB_CLOSE_DELAY=-1
+spring.datasource.username=sa
+spring.datasource.password=sa