DATAJDBC-264 - Polishing.

Added a test. Added an author tag. Minor formatting. Original pull request: spring-projects#88.

Author: schauder

src/main/java/org/springframework/data/jdbc/core/SqlGenerator.java

@@ -39,6 +39,7 @@
  * Generates SQL statements to be used by {@link SimpleJdbcRepository}
  *
  * @author Jens Schauder
+ * @author Yoichi Imai
  */
 class SqlGenerator {
 
@@ -260,6 +261,7 @@ private String createInsertSql(Set<String> additionalColumns) {
 columnNamesForInsert.addAll(additionalColumns);
 
 String tableColumns = String.join(", ", columnNamesForInsert);
+
 String parameterNames = columnNamesForInsert.stream()//
 .map(n -> String.format(":%s", n))//
 .collect(Collectors.joining(", "));

src/test/java/org/springframework/data/jdbc/core/SqlGeneratorUnitTests.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.jdbc.core;
 
+import static java.util.Collections.*;
 import static org.assertj.core.api.Assertions.*;
 
 import java.util.Map;
@@ -26,11 +27,10 @@
 import org.springframework.data.annotation.Id;
 import org.springframework.data.jdbc.core.mapping.PersistentPropertyPathTestUtils;
 import org.springframework.data.mapping.PersistentPropertyPath;
-import org.springframework.data.mapping.PropertyPath;
+import org.springframework.data.relational.core.mapping.NamingStrategy;
 import org.springframework.data.relational.core.mapping.RelationalMappingContext;
 import org.springframework.data.relational.core.mapping.RelationalPersistentEntity;
 import org.springframework.data.relational.core.mapping.RelationalPersistentProperty;
-import org.springframework.data.relational.core.mapping.NamingStrategy;
 
 /**
  * Unit tests for the {@link SqlGenerator}.
@@ -46,10 +46,16 @@ public class SqlGeneratorUnitTests {
 @Before
 public void setUp() {
 
+this.sqlGenerator = createSqlGenerator(DummyEntity.class);
+}
+
+SqlGenerator createSqlGenerator(Class<?> type) {
+
 NamingStrategy namingStrategy = new PrefixingNamingStrategy();
 RelationalMappingContext context = new RelationalMappingContext(namingStrategy);
-RelationalPersistentEntity<?> persistentEntity = context.getRequiredPersistentEntity(DummyEntity.class);
-this.sqlGenerator = new SqlGenerator(context, persistentEntity, new SqlGeneratorSource(context));
+RelationalPersistentEntity<?> persistentEntity = context.getRequiredPersistentEntity(type);
+
+return new SqlGenerator(context, persistentEntity, new SqlGeneratorSource(context));
 }
 
 @Test // DATAJDBC-112
@@ -170,10 +176,20 @@ public void findAllByPropertyWithKeyOrdered() {
 + "WHERE back-ref = :back-ref " + "ORDER BY key-column");
 }
 
+@Test // DATAJDBC-264
+public void getInsertForEmptyColumnList() {
+
+SqlGenerator sqlGenerator = createSqlGenerator(IdOnlyEntity.class);
+
+String insert = sqlGenerator.getInsert(emptySet());
+
+assertThat(insert).endsWith("()");
+}
 
 private PersistentPropertyPath<RelationalPersistentProperty> getPath(String path, Class<?> base) {
 return PersistentPropertyPathTestUtils.getPath(context, path, base);
 }
+
 @SuppressWarnings("unused")
 static class DummyEntity {
 
@@ -212,4 +228,11 @@ public String getColumnName(RelationalPersistentProperty property) {
 }
 
 }
+
+@SuppressWarnings("unused")
+static class IdOnlyEntity {
+
+@Id Long id;
+}
+
 }