From 1f0dfe7dddbfab22d1fde22329057e2145c0f588 Mon Sep 17 00:00:00 2001
From: stvort <stvort@mail.ru>
Date: Sat, 2 Apr 2022 14:25:20 +0400
Subject: [PATCH] 2022-02 spring-09-jpql updated

---
 .../OtusStudentRepositoryJpaTest.java         | 55 +++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/2022-02/spring-09-jpql/jpql-class-work/jpql-solution-final/src/test/java/ru/otus/example/ormdemo/repositories/OtusStudentRepositoryJpaTest.java b/2022-02/spring-09-jpql/jpql-class-work/jpql-solution-final/src/test/java/ru/otus/example/ormdemo/repositories/OtusStudentRepositoryJpaTest.java
index da64c75f..c02c46af 100644
--- a/2022-02/spring-09-jpql/jpql-class-work/jpql-solution-final/src/test/java/ru/otus/example/ormdemo/repositories/OtusStudentRepositoryJpaTest.java
+++ b/2022-02/spring-09-jpql/jpql-class-work/jpql-solution-final/src/test/java/ru/otus/example/ormdemo/repositories/OtusStudentRepositoryJpaTest.java
@@ -2,14 +2,21 @@ package ru.otus.example.ormdemo.repositories;
 
 import lombok.val;
 import org.hibernate.SessionFactory;
+import org.hibernate.boot.registry.StandardServiceRegistry;
+import org.hibernate.engine.jdbc.spi.JdbcServices;
+import org.hibernate.engine.jdbc.spi.SqlStatementLogger;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
 import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager;
 import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
 import ru.otus.example.ormdemo.models.OtusStudent;
 
+import java.lang.reflect.Field;
+import java.util.concurrent.atomic.AtomicInteger;
+
 import static org.assertj.core.api.Assertions.assertThat;
 
 @DisplayName("Репозиторий на основе Jpa для работы со студентами ")
@@ -37,6 +44,7 @@ class OtusStudentRepositoryJpaTest {
                 .usingRecursiveComparison().isEqualTo(expectedStudent);
     }
 
+
     @DisplayName("должен загружать список всех студентов с полной информацией о них")
     @Test
     void shouldReturnCorrectStudentsListWithAllInfo() {
@@ -55,4 +63,51 @@ class OtusStudentRepositoryJpaTest {
         System.out.println("----------------------------------------------------------------------------------------------------------\n\n\n\n");
         assertThat(sessionFactory.getStatistics().getPrepareStatementCount()).isEqualTo(EXPECTED_QUERIES_COUNT);
     }
+
+    @DirtiesContext(methodMode = DirtiesContext.MethodMode.AFTER_METHOD)
+    @DisplayName("должен загружать ожидаемый список студентов по номеру страницы")
+    @Test
+    void shouldReturnCorrectStudentsListByPage() {
+        AtomicInteger studentsSelectionsCount = new AtomicInteger(0);
+        applyCustomSqlStatementLogger(new SqlStatementLogger(true, false, false, 0) {
+            @Override
+            public void logStatement(String statement) {
+                if (!statement.contains("count") && statement.contains("from otus_students")) {
+                    studentsSelectionsCount.incrementAndGet();
+                    assertThat(statement).contains("offset").contains("limit");
+                }
+                super.logStatement(statement);
+            }
+        });
+
+
+        var studentsCount = em.getEntityManager()
+                .createQuery("select count(s) from OtusStudent s", Long.class).getSingleResult();
+        var pageNum = 2;
+        var pageSize = 3;
+        var pagesCount = (long) Math.ceil(studentsCount * 1d / pageSize);
+
+        var query = em.getEntityManager().createQuery("select s from OtusStudent s ", OtusStudent.class);
+        // Так не будет offset + limit из-за того, что студент может занимать больше одной строки набора данных
+        // var query = em.getEntityManager().createQuery("select s from OtusStudent s join fetch s.courses c", OtusStudent.class);
+        var students = query.setFirstResult(pageNum * pageSize).setMaxResults(pageSize).getResultList();
+
+        assertThat(pagesCount).isEqualTo(4);
+        assertThat(students).isNotNull().hasSize(pageSize);
+        assertThat(studentsSelectionsCount.get()).isEqualTo(1);
+    }
+
+    private void applyCustomSqlStatementLogger(SqlStatementLogger customSqlStatementLogger) {
+        StandardServiceRegistry serviceRegistry = em.getEntityManager().getEntityManagerFactory()
+                .unwrap(SessionFactory.class).getSessionFactoryOptions().getServiceRegistry();
+        var jdbcServices = serviceRegistry.getService(JdbcServices.class);
+        try {
+            Field field = jdbcServices.getClass().getDeclaredField("sqlStatementLogger");
+            field.setAccessible(true);
+            field.set(jdbcServices, customSqlStatementLogger);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
 }
\ No newline at end of file