Test setMaxResults with entity graphs

orm/hibernate-orm-6/src/test/java/org/hibernate/bugs/MaxResultsTestCase.java

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+/*
+ * Copyright 2014 JBoss Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.hibernate.bugs;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.hibernate.Session;
+import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.cfg.Configuration;
+import org.hibernate.graph.GraphSemantic;
+import org.hibernate.graph.RootGraph;
+
+import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.junit.Test;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.EntityGraph;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class MaxResultsTestCase extends BaseCoreFunctionalTestCase {
+
+	// Add your entities here.
+	@Override
+	protected Class[] getAnnotatedClasses() {
+		return new Class[] {Book.class, Author.class};
+	}
+
+	// If those mappings reside somewhere other than resources/org/hibernate/test, change this.
+	@Override
+	protected String getBaseForMappings() {
+		return "org/hibernate/test/";
+	}
+
+	// Add in any settings that are specific to your test.  See resources/hibernate.properties for the defaults.
+	@Override
+	protected void configure(Configuration configuration) {
+		super.configure( configuration );
+
+		configuration.setProperty( AvailableSettings.SHOW_SQL, Boolean.TRUE.toString() );
+		configuration.setProperty( AvailableSettings.FORMAT_SQL, Boolean.TRUE.toString() );
+		//configuration.setProperty( AvailableSettings.GENERATE_STATISTICS, "true" );
+	}
+
+	public List<Author> createEntities() {
+		Author author1 = new Author();
+		author1.setName("Author1");
+
+		Book book1 = new Book();
+		book1.setTitle("Book 1");
+		book1.setPages(50);
+		author1.addBook( book1 );
+
+		Book book2 = new Book();
+		book2.setTitle("Book 2");
+		book2.setPages(20);
+		author1.addBook( book2 );
+
+		Author author2 = new Author();
+		author2.setName("Author2");
+		return List.of( author2, author1 );
+	}
+
+	@Test
+	public void testMaxResultsWithEntityGraph() {
+		test( "FROM Author a WHERE a.name LIKE :name ORDER BY a.name" );
+	}
+
+	@Test
+	public void testWorkingApproach() {
+		test( "FROM Author a left join fetch a.books WHERE a.name LIKE :name ORDER BY a.name" );
+	}
+
+	private void test(String query) {
+		try (Session s = openSession()) {
+			s.beginTransaction();
+			for ( Author author : createEntities() ) {
+				s.persist( author );
+			}
+			s.getTransaction().commit();
+		}
+		Author author = null;
+		try (Session s = openSession()) {
+			s.beginTransaction();
+			author = s
+					.createSelectionQuery( query, Author.class )
+					.setParameter( "name", "Author%" )
+					.setMaxResults( 1 )
+					.setEntityGraph( createEntityGraph( s ), GraphSemantic.LOAD )
+					.getSingleResult();
+			s.getTransaction().commit();
+		}
+		assertThat( author.getBooks() ).hasSize( 2 );
+	}
+
+	private EntityGraph<Author> createEntityGraph(Session session) {
+		RootGraph<Author> rootGraph = session.createEntityGraph( Author.class );
+		rootGraph.addAttributeNode( "books" );
+		return rootGraph;
+	}
+
+	@Entity(name = "Author")
+	public static class Author {
+
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		private String name;
+
+		@OneToMany(cascade = CascadeType.ALL, mappedBy = "author")
+		private Set<Book> books = new HashSet<>();
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public Set<Book> getBooks() {
+			return books;
+		}
+
+		public void setBooks(Set<Book> books) {
+			this.books = books;
+		}
+
+		public void addBook(Book book) {
+			books.add( book );
+			book.author = this;
+		}
+
+		@Override
+		public String toString() {
+			return id + ":" + name;
+		}
+	}
+
+	@Entity(name = "Book")
+	public static class Book {
+
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		private String title;
+
+		private int pages;
+
+		@ManyToOne
+		private Author author;
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getTitle() {
+			return title;
+		}
+
+		public void setTitle(String title) {
+			this.title = title;
+		}
+
+		public int getPages() {
+			return pages;
+		}
+
+		public void setPages(int pages) {
+			this.pages = pages;
+		}
+
+		public Author getAuthor() {
+			return author;
+		}
+
+		public void setAuthor(Author author) {
+			this.author = author;
+		}
+
+		@Override
+		public String toString() {
+			return id + ":" + title + ":" + pages;
+		}
+	}
+}