Simplified EntityRowMapper.

Removes an unused field and moves operations into  constructor, to make the mapRow method simpler.

Closes #1974

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/EntityRowMapper.java

@@ -22,8 +22,8 @@
 import org.springframework.data.relational.core.mapping.PersistentPropertyPathExtension;
 import org.springframework.data.relational.core.mapping.RelationalPersistentEntity;
 import org.springframework.data.relational.domain.RowDocument;
+import org.springframework.data.util.TypeInformation;
 import org.springframework.jdbc.core.RowMapper;
-import org.springframework.lang.Nullable;
 
 /**
  * Maps a {@link ResultSet} to an entity of type {@code T}, including entities referenced. This {@link RowMapper} might
@@ -38,10 +38,16 @@
  */
 public class EntityRowMapper<T> implements RowMapper<T> {
 
-	private final RelationalPersistentEntity<T> entity;
-	private final AggregatePath path;
+	private final TypeInformation<T> typeInformation;
 	private final JdbcConverter converter;
-	private final @Nullable Identifier identifier;
+	private final Identifier identifier;
+
+	private EntityRowMapper(TypeInformation<T> typeInformation, JdbcConverter converter, Identifier identifier) {
+
+		this.typeInformation = typeInformation;
+		this.converter = converter;
+		this.identifier = identifier;
+	}
 
 	/**
 	 * @deprecated use {@link EntityRowMapper#EntityRowMapper(AggregatePath, JdbcConverter, Identifier)} instead
@@ -58,29 +64,19 @@ public EntityRowMapper(PersistentPropertyPathExtension path, JdbcConverter conve
 
 	@SuppressWarnings("unchecked")
 	public EntityRowMapper(AggregatePath path, JdbcConverter converter, Identifier identifier) {
-
-		this.entity = (RelationalPersistentEntity<T>) path.getLeafEntity();
-		this.path = path;
-		this.converter = converter;
-		this.identifier = identifier;
+		this(((RelationalPersistentEntity<T>) path.getRequiredLeafEntity()).getTypeInformation(), converter, identifier);
 	}
 
 	public EntityRowMapper(RelationalPersistentEntity<T> entity, JdbcConverter converter) {
-
-		this.entity = entity;
-		this.path = null;
-		this.converter = converter;
-		this.identifier = null;
+		this(entity.getTypeInformation(), converter, Identifier.empty());
 	}
 
 	@Override
 	public T mapRow(ResultSet resultSet, int rowNumber) throws SQLException {
 
 		RowDocument document = RowDocumentResultSetExtractor.toRowDocument(resultSet);
 
-		return identifier == null //
-				? converter.readAndResolve(entity.getTypeInformation(), document, Identifier.empty()) //
-				: converter.readAndResolve(entity.getTypeInformation(), document, identifier);
+		return converter.readAndResolve(typeInformation, document, identifier);
 	}
 
 }