DATAJDBC-331 - Polishing.

Simplify column name discovery using Optionals utility methods. Add test to verify Column annotation precedence.

Javadoc, formatting.

Original pull request: #117.

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/core/mapping/BasicJdbcPersistentPropertyUnitTests.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.data.jdbc.core.mapping;
 
-import static org.assertj.core.api.Assertions.*;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import lombok.Data;
 
@@ -27,6 +27,7 @@ import java.util.UUID;
 
 import org.assertj.core.api.SoftAssertions;
 import org.junit.Test;
+
 import org.springframework.data.annotation.Id;
 import org.springframework.data.mapping.PropertyHandler;
 import org.springframework.data.relational.core.mapping.BasicRelationalPersistentProperty;
@@ -42,6 +43,7 @@ import org.springframework.data.relational.core.mapping.RelationalPersistentProp
  * @author Jens Schauder
  * @author Oliver Gierke
  * @author Florian Lüdiger
+ * @author Mark Paluch
  */
 public class BasicJdbcPersistentPropertyUnitTests {
 
@@ -51,8 +53,6 @@ public class BasicJdbcPersistentPropertyUnitTests {
 	@Test // DATAJDBC-104
 	public void enumGetsStoredAsString() {
 
-		RelationalPersistentEntity<?> persistentEntity = context.getRequiredPersistentEntity(DummyEntity.class);
-
 		entity.doWithProperties((PropertyHandler<RelationalPersistentProperty>) p -> {
 			switch (p.getName()) {
 				case "someEnum":
@@ -118,6 +118,28 @@ public class BasicJdbcPersistentPropertyUnitTests {
 		softly.assertAll();
 	}
 
+	@Test // DATAJDBC-331
+	public void detectsKeyColumnNameFromColumnAnnotation() {
+
+		RelationalPersistentProperty listProperty = context //
+				.getRequiredPersistentEntity(WithCollections.class) //
+				.getRequiredPersistentProperty("someList");
+
+		assertThat(listProperty.getKeyColumn()).isEqualTo("some_key");
+		assertThat(listProperty.getReverseColumnName()).isEqualTo("some_value");
+	}
+
+	@Test // DATAJDBC-331
+	public void detectsKeyColumnOverrideNameFromMappedCollectionAnnotation() {
+
+		RelationalPersistentProperty listProperty = context //
+				.getRequiredPersistentEntity(WithCollections.class) //
+				.getRequiredPersistentProperty("overrideList");
+
+		assertThat(listProperty.getKeyColumn()).isEqualTo("override_key");
+		assertThat(listProperty.getReverseColumnName()).isEqualTo("override_id");
+	}
+
 	private void checkTargetType(SoftAssertions softly, RelationalPersistentEntity<?> persistentEntity,
 			String propertyName, Class<?> expected) {
 
@@ -138,7 +160,8 @@ public class BasicJdbcPersistentPropertyUnitTests {
 		private final List<String> listField;
 		private final UUID uuid;
 
-		@MappedCollection(idColumn = "dummy_column_name", keyColumn = "dummy_key_column_name") private List<Integer> someList;
+		@MappedCollection(idColumn = "dummy_column_name",
+				keyColumn = "dummy_key_column_name") private List<Integer> someList;
 
 		// DATACMNS-106
 		private @Column("dummy_name") String name;
@@ -157,6 +180,14 @@ public class BasicJdbcPersistentPropertyUnitTests {
 		}
 	}
 
+	@Data
+	private static class WithCollections {
+
+		@Column(value = "some_value", keyColumn = "some_key") List<Integer> someList;
+		@Column(value = "some_value", keyColumn = "some_key") @MappedCollection(idColumn = "override_id",
+				keyColumn = "override_key") List<Integer> overrideList;
+	}
+
 	@SuppressWarnings("unused")
 	private enum SomeEnum {
 		ALPHA

spring-data-relational/src/main/java/org/springframework/data/relational/core/mapping/BasicRelationalPersistentProperty.java

@@ -21,10 +21,8 @@ import java.time.temporal.Temporal;
 import java.util.Date;
 import java.util.LinkedHashMap;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
-import java.util.stream.Stream;
 
 import org.springframework.data.mapping.Association;
 import org.springframework.data.mapping.PersistentEntity;
@@ -32,6 +30,7 @@ import org.springframework.data.mapping.model.AnnotationBasedPersistentProperty;
 import org.springframework.data.mapping.model.Property;
 import org.springframework.data.mapping.model.SimpleTypeHolder;
 import org.springframework.data.util.Lazy;
+import org.springframework.data.util.Optionals;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -88,41 +87,19 @@ public class BasicRelationalPersistentProperty extends AnnotationBasedPersistent
 				.map(Embedded::value) //
 				.orElse(""));
 
-		this.columnName = Lazy.of(() -> Optional.ofNullable( //
-				findAnnotation(Column.class)) //
+		this.columnName = Lazy.of(() -> Optional.ofNullable(findAnnotation(Column.class)) //
 				.map(Column::value) //
-				.filter(StringUtils::hasText)//
-		);
+				.filter(StringUtils::hasText));
 
-		this.collectionIdColumnName = Lazy.of(() ->
-				Stream.concat( //
-						Stream.of( //
-								findAnnotation(MappedCollection.class)) //
-								.filter(Objects::nonNull) //
-								.map(MappedCollection::idColumn), //
-						Stream.of( //
-								findAnnotation(Column.class)) //
-								.filter(Objects::nonNull) //
-								.map(Column::value) //
-				)
-						.filter(StringUtils::hasText)
-						.findFirst()
-		);
+		this.collectionIdColumnName = Lazy.of(() -> Optionals
+				.toStream(Optional.ofNullable(findAnnotation(MappedCollection.class)).map(MappedCollection::idColumn),
+						Optional.ofNullable(findAnnotation(Column.class)).map(Column::value)) //
+				.filter(StringUtils::hasText).findFirst());
 
-		this.collectionKeyColumnName = Lazy.of(() ->
-				Stream.concat( //
-						Stream.of( //
-								findAnnotation(MappedCollection.class)) //
-								.filter(Objects::nonNull) //
-								.map(MappedCollection::keyColumn), //
-						Stream.of( //
-								findAnnotation(Column.class)) //
-								.filter(Objects::nonNull) //
-								.map(Column::keyColumn) //
-				)
-						.filter(StringUtils::hasText)
-						.findFirst()
-		);
+		this.collectionKeyColumnName = Lazy.of(() -> Optionals
+				.toStream(Optional.ofNullable(findAnnotation(MappedCollection.class)).map(MappedCollection::keyColumn),
+						Optional.ofNullable(findAnnotation(Column.class)).map(Column::keyColumn)) //
+				.filter(StringUtils::hasText).findFirst());
 	}
 
 	/*

spring-data-relational/src/main/java/org/springframework/data/relational/core/mapping/MappedCollection.java

@@ -20,12 +20,15 @@ import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
+import java.util.List;
+import java.util.Map;
 
 /**
- * The annotation to configure the mapping from an collection in the database.
+ * The annotation to configure the mapping for a {@link List} or {@link Map} property in the database.
  *
  * @since 1.1
  * @author Bastian Wilhelm
+ * @author Mark Paluch
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ ElementType.FIELD, ElementType.METHOD, ElementType.ANNOTATION_TYPE })
@@ -33,16 +36,18 @@ import java.lang.annotation.Target;
 public @interface MappedCollection {
 
 	/**
-	 * The column name for id column in the corresponding relationship table.
-	 * If the default value (empty String) is used, the column name is resolved by the used
-	 * {@link NamingStrategy} method {@link NamingStrategy#getReverseColumnName(RelationalPersistentProperty)}
+	 * The column name for id column in the corresponding relationship table. Defaults to {@link NamingStrategy} usage if
+	 * the value is empty.
+	 *
+	 * @see NamingStrategy#getReverseColumnName(RelationalPersistentProperty)
 	 */
 	String idColumn() default "";
 
 	/**
-	 * The column name for key columns of List or Map collections in the corresponding relationship table.
-	 * If the default value (empty String) is used, the column name is resolved by the used
-	 * {@link NamingStrategy} method {@link NamingStrategy#getKeyColumn(RelationalPersistentProperty)}
+	 * The column name for key columns of {@link List} or {@link Map} collections in the corresponding relationship table.
+	 * Defaults to {@link NamingStrategy} usage if the value is empty.
+	 *
+	 * @see NamingStrategy#getKeyColumn(RelationalPersistentProperty)
 	 */
 	String keyColumn() default "";
 }

src/main/asciidoc/index.adoc

@@ -1,5 +1,5 @@
 = Spring Data JDBC - Reference Documentation
-Jens Schauder, Jay Bryant, Mark Paluch
+Jens Schauder, Jay Bryant, Mark Paluch, Bastian Wilhelm
 :revnumber: {version}
 :revdate: {localdate}
 :javadoc-base: https://docs.spring.io/spring-data/jdbc/docs/{revnumber}/api/