Spring/spring-data-examples
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Polishing.

Browse Source 
Add WindowIterator example.

See #662
This commit is contained in:
Mark Paluch
2023-05-15 11:46:36 +02:00
parent 1b8872abce
commit b21a6647ae
4 changed files with 66 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
jpa/example/src/main/java/example/springdata/jpa/pagination/Book.java
View File

@@ -15,14 +15,14 @@
*/
package example.springdata.jpa.pagination;
import java.util.Date;
import jakarta.persistence.Entity;
import jakarta.persistence.Id;
import jakarta.persistence.ManyToOne;
import jakarta.persistence.Table;
import lombok.Data;
import java.util.Date;
/**
* @author Christoph Strobl
*/
@@ -31,12 +31,10 @@ import lombok.Data;
@Table(name = "books")
public class Book {
@Id
private String id;
@Id private String id;
private String title;
private String isbn10;
private Date publicationDate;
@ManyToOne
Author author;
@ManyToOne Author author;
}

21
jpa/example/src/main/java/example/springdata/jpa/pagination/BookRepository.java
View File

@@ -28,9 +28,10 @@ import org.springframework.data.repository.ListCrudRepository;
public interface BookRepository extends ListCrudRepository<Book, String> {
/**
* Uses an {@literal offset} based pagination that first sorts the entries by their {@link Book#getPublicationDate() publication_date}
* and then limits the result by dropping the number of rows specified in the {@link Pageable#getOffset() offset} clause.
* To retrieve {@link Page#getTotalElements()} an additional count query is executed.
* Uses an {@literal offset} based pagination that first sorts the entries by their {@link Book#getPublicationDate()
* publication_date} and then limits the result by dropping the number of rows specified in the
* {@link Pageable#getOffset() offset} clause. To retrieve {@link Page#getTotalElements()} an additional count query
* is executed.
*
* @param title
* @param pageable
@@ -39,8 +40,9 @@ public interface BookRepository extends ListCrudRepository<Book, String> {
Page<Book> findByTitleContainsOrderByPublicationDate(String title, Pageable pageable);
/**
* Uses an {@literal offset} based slicing that first sorts the entries by their {@link Book#getPublicationDate() publication_date}
* and then limits the result by dropping the number of rows specified in the {@link Pageable#getOffset() offset} clause.
* Uses an {@literal offset} based slicing that first sorts the entries by their {@link Book#getPublicationDate()
* publication_date} and then limits the result by dropping the number of rows specified in the
* {@link Pageable#getOffset() offset} clause.
*
* @param title
* @param pageable
@@ -49,11 +51,10 @@ public interface BookRepository extends ListCrudRepository<Book, String> {
Slice<Book> findBooksByTitleContainsOrderByPublicationDate(String title, Pageable pageable);
/**
* Depending on the provided {@link ScrollPosition} either {@link org.springframework.data.domain.OffsetScrollPosition offset}
* or {@link org.springframework.data.domain.KeysetScrollPosition keyset} scrolling is possible.
* Scrolling through results requires a stable {@link org.springframework.data.domain.Sort} which is different from
* what {@link Pageable#getSort()} offers.
* The {@literal limit} is defined via the {@literal Top} keyword.
* Depending on the provided {@link ScrollPosition} either {@link org.springframework.data.domain.OffsetScrollPosition
* offset} or {@link org.springframework.data.domain.KeysetScrollPosition keyset} scrolling is possible. Scrolling
* through results requires a stable {@link org.springframework.data.domain.Sort} which is different from what
* {@link Pageable#getSort()} offers. The {@literal limit} is defined via the {@literal Top} keyword.
*
* @param title
* @param scrollPosition

6
jpa/example/src/main/java/example/springdata/jpa/pagination/PagingRepoConfig.java
View File

@@ -22,7 +22,5 @@ import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
* @author Christoph Strobl
*/
@SpringBootApplication
@EnableJpaRepositories(repositoryBaseClass = BookRepository.class)
class PagingRepoConfig {
}
@EnableJpaRepositories(basePackageClasses = BookRepository.class)
class PagingRepoConfig {}

81
jpa/example/src/test/java/example/springdata/jpa/pagination/PaginationTests.java
View File

@@ -15,7 +15,9 @@
*/
package example.springdata.jpa.pagination;
import static org.assertj.core.api.AssertionsForClassTypes.*;
import static org.assertj.core.api.Assertions.*;
import jakarta.persistence.EntityManager;
import java.util.List;
import java.util.Random;
@@ -24,13 +26,12 @@ import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import com.github.javafaker.Faker;
import jakarta.persistence.EntityManager;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.domain.KeysetScrollPosition;
import org.springframework.data.domain.OffsetScrollPosition;
@@ -40,15 +41,18 @@ import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.ScrollPosition;
import org.springframework.data.domain.Slice;
import org.springframework.data.domain.Window;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.data.domain.WindowIterator;
import org.springframework.data.util.Streamable;
import com.github.javafaker.Faker;
/**
* Show different types of paging styles using {@link Page}, {@link org.springframework.data.domain.Slice} and {@link Window}
* Show different types of paging styles using {@link Page}, {@link Slice} and {@link Window}.
*
* @author Christoph Strobl
* @author Mark Paluch
*/
@SpringBootTest
@Transactional
@DataJpaTest
class PaginationTests {
@Configuration
@@ -57,8 +61,7 @@ class PaginationTests {
}
@Autowired
BookRepository books;
@Autowired BookRepository books;
@BeforeEach
void setUp() {
@@ -71,10 +74,9 @@ class PaginationTests {
}
/**
* Page through the results using an offset/limit approach where the server skips over the number of results
* specified via {@link Pageable#getOffset()}.
* The {@link Page} return type will run an additional {@literal count} query to read the total number of matching rows
* on each request.
* Page through the results using an offset/limit approach where the server skips over the number of results specified
* via {@link Pageable#getOffset()}. The {@link Page} return type will run an additional {@literal count} query to
* read the total number of matching rows on each request.
*/
@Test
void pageThroughResultsWithSkipAndLimit() {
@@ -93,9 +95,9 @@ class PaginationTests {
/**
* Run through the results using an offset/limit approach where the server skips over the number of results specified
* via {@link Pageable#getOffset()}.
* No additional {@literal count} query to read the total number of matching rows is issued. Still {@link Slice} requests,
* but does not emit, one row more than specified via {@link Page#getSize()} to feed {@link Slice#hasNext()}
* via {@link Pageable#getOffset()}. No additional {@literal count} query to read the total number of matching rows is
* issued. Still {@link Slice} requests, but does not emit, one row more than specified via {@link Page#getSize()} to
* feed {@link Slice#hasNext()}
*/
@Test
void sliceThroughResultsWithSkipAndLimit() {
@@ -133,11 +135,28 @@ class PaginationTests {
} while (window.hasNext());
}
/**
* Scroll through the results using an offset/limit approach where the server skips over the number of results
* specified via {@link OffsetScrollPosition#getOffset()} using {@link WindowIterator}.
* <p>
* This approach is similar to the {@link #sliceThroughResultsWithSkipAndLimit() slicing one}.
*/
@Test
void scrollThroughResultsUsingWindowIteratorWithSkipAndLimit() {
WindowIterator<Book> iterator = WindowIterator
.of(scrollPosition -> books.findTop2ByTitleContainsOrderByPublicationDate("the-crazy-book-", scrollPosition))
.startingAt(OffsetScrollPosition.initial());
List<Book> allBooks = Streamable.of(() -> iterator).stream().toList();
assertThat(allBooks).hasSize(50);
}
/**
* Scroll through the results using an index based approach where the {@link KeysetScrollPosition#getKeys() keyset}
* keeps track of already seen values to resume scrolling by altering the where clause to only return rows after the
* values contained in the keyset.
* Set {@literal logging.level.org.hibernate.SQL=debug} to show the modified query in the log.
* values contained in the keyset. Set {@literal logging.level.org.hibernate.SQL=debug} to show the modified query in
* the log.
*/
@Test
void scrollThroughResultsWithKeyset() {
@@ -155,8 +174,7 @@ class PaginationTests {
// --> Test Data
@Autowired
EntityManager em;
@Autowired EntityManager em;
private List<Author> createAuthors(Faker faker) {
@@ -176,18 +194,17 @@ class PaginationTests {
private List<Book> createBooks(Faker faker, List<Author> authors) {
Random rand = new Random();
return IntStream.range(0, 100)
.mapToObj(id -> {
return IntStream.range(0, 100).mapToObj(id -> {
Book book = new Book();
book.setId("book-%03d".formatted(id));
book.setTitle(faker.book().title());
book.setIsbn10(UUID.randomUUID().toString().substring(0, 10));
book.setPublicationDate(faker.date().past(5000, TimeUnit.DAYS));
book.setAuthor(authors.get(rand.nextInt(authors.size())));
Book book = new Book();
book.setId("book-%03d".formatted(id));
book.setTitle((id % 2 == 0 ? "the-crazy-book-" : "") + faker.book().title());
book.setIsbn10(UUID.randomUUID().toString().substring(0, 10));
book.setPublicationDate(faker.date().past(5000, TimeUnit.DAYS));
book.setAuthor(authors.get(rand.nextInt(authors.size())));
em.persist(book);
return book;
}).collect(Collectors.toList());
em.persist(book);
return book;
}).collect(Collectors.toList());
}
}