fix(sqlserver): prevent cast from NVARCHAR to VARCHAR

Related: #158

.github/workflows/ci.yml

@@ -93,3 +93,31 @@ jobs:
         run: mvn -B test
         env:
           spring_profiles_active: mysql
+
+  test-sqlserver:
+    runs-on: ubuntu-latest
+
+    services:
+      sqlserver:
+        image: mcr.microsoft.com/mssql/server:2022-preview-ubuntu-22.04
+        ports:
+          - 1433:1433
+        env:
+          ACCEPT_EULA: Y
+          MSSQL_SA_PASSWORD: "Changeit_123"
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: 17
+          distribution: adopt
+          cache: maven
+
+      - name: Test with Maven
+        run: mvn -B test
+        env:
+          spring_profiles_active: sqlserver

compose.yaml

@@ -0,0 +1,23 @@
+services:
+  postgres:
+    image: postgres:14
+    ports:
+      - 5432:5432
+    environment:
+      POSTGRES_PASSWORD: "postgres"
+
+  sqlserver:
+    image: mcr.microsoft.com/mssql/server:2022-preview-ubuntu-22.04
+    ports:
+      - 1433:1433
+    environment:
+      ACCEPT_EULA: Y
+      MSSQL_SA_PASSWORD: "Changeit_123"
+
+  mysql:
+    image: mysql:5.7
+    ports:
+      - 3306:3306
+    environment:
+      MYSQL_DATABASE: test
+      MYSQL_ROOT_PASSWORD: changeit

pom.xml

@@ -163,6 +163,13 @@
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>com.microsoft.sqlserver</groupId>
+			<artifactId>mssql-jdbc</artifactId>
+			<version>12.6.1.jre11</version>
+			<scope>test</scope>
+		</dependency>
+
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-reload4j</artifactId>

src/main/java/org/springframework/data/jpa/datatables/GlobalFilter.java

@@ -34,7 +34,16 @@ private String escapeValue(String filterValue) {
     @Override
     public Predicate createPredicate(From<?, ?> from, CriteriaBuilder criteriaBuilder, String attributeName) {
         Expression<?> expression = from.get(attributeName);
-        return criteriaBuilder.like(criteriaBuilder.lower(expression.as(String.class)), escapedRawValue, '~');
+        return criteriaBuilder.like(criteriaBuilder.lower(castAsStringIfNeeded(expression)), escapedRawValue, '~');
+    }
+
+    @SuppressWarnings("unchecked")
+    private Expression<String> castAsStringIfNeeded(Expression<?> expression) {
+        if (expression.getJavaType() == String.class) {
+            return (Expression<String>) expression;
+        } else {
+            return expression.as(String.class);
+        }
     }
 
     @Override

src/test/java/org/springframework/data/jpa/datatables/Config.java

@@ -54,6 +54,17 @@ public DataSource dataSource_PostgreSQL() throws SQLException {
     return dataSource;
   }
 
+  @Bean
+  @Profile("sqlserver")
+  public DataSource dataSource_SQLServer() throws SQLException {
+    DriverManagerDataSource dataSource = new DriverManagerDataSource();
+    dataSource.setDriverClassName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
+    dataSource.setUrl("jdbc:sqlserver://localhost:1433;encrypt=false;");
+    dataSource.setUsername("sa");
+    dataSource.setPassword("Changeit_123");
+    return dataSource;
+  }
+
   @Bean
   public SessionFactory entityManagerFactory(DataSource dataSource) throws Exception {
     LocalSessionFactoryBean factory = new LocalSessionFactoryBean();

src/test/java/org/springframework/data/jpa/datatables/repository/User.java

@@ -0,0 +1,24 @@
+package org.springframework.data.jpa.datatables.repository;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import lombok.Data;
+import org.hibernate.annotations.Nationalized;
+
+@Entity
+@Data
+@Table(name = "users")
+public class User {
+
+    @Id long id;
+    @Nationalized String name;
+
+    public User() {
+    }
+
+    public User(long id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+}

src/test/java/org/springframework/data/jpa/datatables/repository/UserRepository.java

@@ -0,0 +1,4 @@
+package org.springframework.data.jpa.datatables.repository;
+
+public interface UserRepository extends DataTablesRepository<User, Long> {
+}

src/test/java/org/springframework/data/jpa/datatables/repository/UserRepositoryTest.java

@@ -0,0 +1,43 @@
+package org.springframework.data.jpa.datatables.repository;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.jpa.datatables.Config;
+import org.springframework.data.jpa.datatables.mapping.DataTablesInput;
+import org.springframework.data.jpa.datatables.mapping.DataTablesOutput;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.DisabledIf;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@ExtendWith(SpringExtension.class)
+@ContextConfiguration(classes = Config.class)
+public class UserRepositoryTest {
+
+    @Autowired private UserRepository userRepository;
+
+    private void init() {
+        userRepository.save(new User(1L, "r"));
+        userRepository.save(new User(2L, "ř"));
+        userRepository.save(new User(3L, "ŗ"));
+        userRepository.save(new User(4L, "ɍ"));
+        userRepository.save(new User(5L, "ȓ"));
+    }
+
+    @Test
+    @DisabledIf(value = "#{'${spring.profiles.active}' == 'mysql'}", loadContext = true)
+    void withNationalizedColumn() {
+        init();
+
+        DataTablesInput input = new DataTablesInput();
+        input.addColumn("name", true, true, "ř");
+
+        DataTablesOutput<User> output = userRepository.findAll(input);
+
+        assertThat(output.getRecordsFiltered()).isEqualTo(1);
+        assertThat(output.getData().get(0).getId()).isEqualTo(2L);
+    }
+
+}