Argument name based constructor auto-mapping

src/main/java/org/apache/ibatis/builder/xml/XMLConfigBuilder.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -269,6 +269,7 @@ private void settingsElement(Properties props) {
     configuration.setLogPrefix(props.getProperty("logPrefix"));
     configuration.setConfigurationFactory(resolveClass(props.getProperty("configurationFactory")));
     configuration.setShrinkWhitespacesInSql(booleanValueOf(props.getProperty("shrinkWhitespacesInSql"), false));
+    configuration.setArgNameBasedConstructorAutoMapping(booleanValueOf(props.getProperty("argNameBasedConstructorAutoMapping"), false));
     configuration.setDefaultSqlProviderType(resolveClass(props.getProperty("defaultSqlProviderType")));
     configuration.setNullableOnForEach(booleanValueOf(props.getProperty("nullableOnForEach"), false));
   }

src/main/java/org/apache/ibatis/executor/resultset/DefaultResultSetHandler.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -16,19 +16,24 @@
 package org.apache.ibatis.executor.resultset;
 
 import java.lang.reflect.Constructor;
+import java.lang.reflect.Parameter;
 import java.sql.CallableStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.text.MessageFormat;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 
 import org.apache.ibatis.annotations.AutomapConstructor;
+import org.apache.ibatis.annotations.Param;
 import org.apache.ibatis.binding.MapperMethod.ParamMap;
 import org.apache.ibatis.cache.CacheKey;
 import org.apache.ibatis.cursor.Cursor;
@@ -95,6 +100,7 @@ public class DefaultResultSetHandler implements ResultSetHandler {
 
   // Cached Automappings
   private final Map<String, List<UnMappedColumnAutoMapping>> autoMappingsCache = new HashMap<>();
+  private final Map<String, List<String>> constructorAutoMappingColumns = new HashMap<>();
 
   // temporary marking flag that indicate using constructor mapping (use field to reduce memory usage)
   private boolean useConstructorMappings;
@@ -519,6 +525,11 @@ private List<UnMappedColumnAutoMapping> createAutomaticMappings(ResultSetWrapper
     if (autoMapping == null) {
       autoMapping = new ArrayList<>();
       final List<String> unmappedColumnNames = rsw.getUnmappedColumnNames(resultMap, columnPrefix);
+      // Remove the entry to release the memory
+      List<String> mappedInConstructorAutoMapping = constructorAutoMappingColumns.remove(mapKey);
+      if (mappedInConstructorAutoMapping != null) {
+        unmappedColumnNames.removeAll(mappedInConstructorAutoMapping);
+      }
       for (String columnName : unmappedColumnNames) {
         String propertyName = columnName;
         if (columnPrefix != null && !columnPrefix.isEmpty()) {
@@ -655,7 +666,7 @@ private Object createResultObject(ResultSetWrapper rsw, ResultMap resultMap, Lis
     } else if (resultType.isInterface() || metaType.hasDefaultConstructor()) {
       return objectFactory.create(resultType);
     } else if (shouldApplyAutomaticMappings(resultMap, false)) {
-      return createByConstructorSignature(rsw, resultType, constructorArgTypes, constructorArgs);
+      return createByConstructorSignature(rsw, resultMap, columnPrefix, resultType, constructorArgTypes, constructorArgs);
     }
     throw new ExecutorException("Do not know how to create an instance of " + resultType);
   }
@@ -687,23 +698,61 @@ Object createParameterizedResultObject(ResultSetWrapper rsw, Class<?> resultType
     return foundValues ? objectFactory.create(resultType, constructorArgTypes, constructorArgs) : null;
   }
 
-  private Object createByConstructorSignature(ResultSetWrapper rsw, Class<?> resultType, List<Class<?>> constructorArgTypes, List<Object> constructorArgs) throws SQLException {
-    final Constructor<?>[] constructors = resultType.getDeclaredConstructors();
-    final Constructor<?> defaultConstructor = findDefaultConstructor(constructors);
-    if (defaultConstructor != null) {
-      return createUsingConstructor(rsw, resultType, constructorArgTypes, constructorArgs, defaultConstructor);
+  private Object createByConstructorSignature(ResultSetWrapper rsw, ResultMap resultMap, String columnPrefix, Class<?> resultType,
+      List<Class<?>> constructorArgTypes, List<Object> constructorArgs) throws SQLException {
+    return applyConstructorAutomapping(rsw, resultMap, columnPrefix, resultType, constructorArgTypes, constructorArgs,
+        findConstructorForAutomapping(resultType, rsw).orElseThrow(() -> new ExecutorException(
+            "No constructor found in " + resultType.getName() + " matching " + rsw.getClassNames())));
+  }
+
+  private Optional<Constructor<?>> findConstructorForAutomapping(final Class<?> resultType, ResultSetWrapper rsw) {
+    Constructor<?>[] constructors = resultType.getDeclaredConstructors();
+    if (constructors.length == 1) {
+      return Optional.of(constructors[0]);
+    }
+    for (final Constructor<?> constructor : constructors) {
+      if (constructor.isAnnotationPresent(AutomapConstructor.class)) {
+        return Optional.of(constructor);
+      }
+    }
+    if (configuration.isArgNameBasedConstructorAutoMapping()) {
+      // Finding-best-match type implementation is possible,
+      // but using @AutomapConstructor seems sufficient.
+      throw new ExecutorException(MessageFormat.format(
+          "'argNameBasedConstructorAutoMapping' is enabled and the class ''{0}'' has multiple constructors, so @AutomapConstructor must be added to one of the constructors.",
+          resultType.getName()));
     } else {
-      for (Constructor<?> constructor : constructors) {
-        if (allowedConstructorUsingTypeHandlers(constructor, rsw.getJdbcTypes())) {
-          return createUsingConstructor(rsw, resultType, constructorArgTypes, constructorArgs, constructor);
-        }
+      return Arrays.stream(constructors).filter(x -> findUsableConstructorByArgTypes(x, rsw.getJdbcTypes())).findAny();
+    }
+  }
+
+  private boolean findUsableConstructorByArgTypes(final Constructor<?> constructor, final List<JdbcType> jdbcTypes) {
+    final Class<?>[] parameterTypes = constructor.getParameterTypes();
+    if (parameterTypes.length != jdbcTypes.size()) {
+      return false;
+    }
+    for (int i = 0; i < parameterTypes.length; i++) {
+      if (!typeHandlerRegistry.hasTypeHandler(parameterTypes[i], jdbcTypes.get(i))) {
+        return false;
       }
     }
-    throw new ExecutorException("No constructor found in " + resultType.getName() + " matching " + rsw.getClassNames());
+    return true;
   }
 
-  private Object createUsingConstructor(ResultSetWrapper rsw, Class<?> resultType, List<Class<?>> constructorArgTypes, List<Object> constructorArgs, Constructor<?> constructor) throws SQLException {
+  private Object applyConstructorAutomapping(ResultSetWrapper rsw, ResultMap resultMap, String columnPrefix, Class<?> resultType, List<Class<?>> constructorArgTypes, List<Object> constructorArgs, Constructor<?> constructor) throws SQLException {
     boolean foundValues = false;
+    if (configuration.isArgNameBasedConstructorAutoMapping()) {
+      foundValues = applyArgNameBasedConstructorAutoMapping(rsw, resultMap, columnPrefix, resultType, constructorArgTypes, constructorArgs,
+          constructor, foundValues);
+    } else {
+      foundValues = applyColumnOrderBasedConstructorAutomapping(rsw, constructorArgTypes, constructorArgs, constructor,
+          foundValues);
+    }
+    return foundValues ? objectFactory.create(resultType, constructorArgTypes, constructorArgs) : null;
+  }
+
+  private boolean applyColumnOrderBasedConstructorAutomapping(ResultSetWrapper rsw, List<Class<?>> constructorArgTypes,
+      List<Object> constructorArgs, Constructor<?> constructor, boolean foundValues) throws SQLException {
     for (int i = 0; i < constructor.getParameterTypes().length; i++) {
       Class<?> parameterType = constructor.getParameterTypes()[i];
       String columnName = rsw.getColumnNames().get(i);
@@ -713,33 +762,58 @@ private Object createUsingConstructor(ResultSetWrapper rsw, Class<?> resultType,
       constructorArgs.add(value);
       foundValues = value != null || foundValues;
     }
-    return foundValues ? objectFactory.create(resultType, constructorArgTypes, constructorArgs) : null;
+    return foundValues;
   }
 
-  private Constructor<?> findDefaultConstructor(final Constructor<?>[] constructors) {
-    if (constructors.length == 1) {
-      return constructors[0];
-    }
-
-    for (final Constructor<?> constructor : constructors) {
-      if (constructor.isAnnotationPresent(AutomapConstructor.class)) {
-        return constructor;
+  private boolean applyArgNameBasedConstructorAutoMapping(ResultSetWrapper rsw, ResultMap resultMap, String columnPrefix, Class<?> resultType,
+      List<Class<?>> constructorArgTypes, List<Object> constructorArgs, Constructor<?> constructor, boolean foundValues)
+      throws SQLException {
+    List<String> missingArgs = null;
+    Parameter[] params = constructor.getParameters();
+    for (Parameter param : params) {
+      boolean columnNotFound = true;
+      Param paramAnno = param.getAnnotation(Param.class);
+      String paramName = paramAnno == null ? param.getName() : paramAnno.value();
+      for (String columnName : rsw.getColumnNames()) {
+        if (columnMatchesParam(columnName, paramName, columnPrefix)) {
+          Class<?> paramType = param.getType();
+          TypeHandler<?> typeHandler = rsw.getTypeHandler(paramType, columnName);
+          Object value = typeHandler.getResult(rsw.getResultSet(), columnName);
+          constructorArgTypes.add(paramType);
+          constructorArgs.add(value);
+          final String mapKey = resultMap.getId() + ":" + columnPrefix;
+          if (!autoMappingsCache.containsKey(mapKey)) {
+            MapUtil.computeIfAbsent(constructorAutoMappingColumns, mapKey, k -> new ArrayList<>()).add(columnName);
+          }
+          columnNotFound = false;
+          foundValues = value != null || foundValues;
+        }
+      }
+      if (columnNotFound) {
+        if (missingArgs == null) {
+          missingArgs = new ArrayList<>();
+        }
+        missingArgs.add(paramName);
       }
     }
-    return null;
+    if (foundValues && constructorArgs.size() < params.length) {
+      throw new ExecutorException(MessageFormat.format("Constructor auto-mapping of ''{1}'' failed "
+          + "because ''{0}'' were not found in the result set; "
+          + "Available columns are ''{2}'' and mapUnderscoreToCamelCase is ''{3}''.",
+          missingArgs, constructor, rsw.getColumnNames(), configuration.isMapUnderscoreToCamelCase()));
+    }
+    return foundValues;
   }
 
-  private boolean allowedConstructorUsingTypeHandlers(final Constructor<?> constructor, final List<JdbcType> jdbcTypes) {
-    final Class<?>[] parameterTypes = constructor.getParameterTypes();
-    if (parameterTypes.length != jdbcTypes.size()) {
-      return false;
-    }
-    for (int i = 0; i < parameterTypes.length; i++) {
-      if (!typeHandlerRegistry.hasTypeHandler(parameterTypes[i], jdbcTypes.get(i))) {
+  private boolean columnMatchesParam(String columnName, String paramName, String columnPrefix) {
+    if (columnPrefix != null) {
+      if (!columnName.toUpperCase(Locale.ENGLISH).startsWith(columnPrefix)) {
         return false;
       }
+      columnName = columnName.substring(columnPrefix.length());
     }
-    return true;
+    return paramName
+        .equalsIgnoreCase(configuration.isMapUnderscoreToCamelCase() ? columnName.replace("_", "") : columnName);
   }
 
   private Object createPrimitiveResultObject(ResultSetWrapper rsw, ResultMap resultMap, String columnPrefix) throws SQLException {

src/main/java/org/apache/ibatis/session/Configuration.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -115,6 +115,7 @@ public class Configuration {
   protected boolean returnInstanceForEmptyRow;
   protected boolean shrinkWhitespacesInSql;
   protected boolean nullableOnForEach;
+  protected boolean argNameBasedConstructorAutoMapping;
 
   protected String logPrefix;
   protected Class<? extends Log> logImpl;
@@ -320,6 +321,14 @@ public boolean isNullableOnForEach() {
     return nullableOnForEach;
   }
 
+  public boolean isArgNameBasedConstructorAutoMapping() {
+    return argNameBasedConstructorAutoMapping;
+  }
+
+  public void setArgNameBasedConstructorAutoMapping(boolean argNameBasedConstructorAutoMapping) {
+    this.argNameBasedConstructorAutoMapping = argNameBasedConstructorAutoMapping;
+  }
+
   public String getDatabaseId() {
     return databaseId;
   }

src/site/es/xdoc/configuration.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 
-       Copyright 2009-2021 the original author or authors.
+       Copyright 2009-2022 the original author or authors.
 
        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
@@ -591,6 +591,20 @@ SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader, environ
                 false
               </td>
             </tr>
+            <tr>
+              <td>
+                argNameBasedConstructorAutoMapping
+              </td>
+              <td>
+                When applying constructor auto-mapping, argument name is used to search the column to map instead of relying on the column order. (Since 3.5.10)
+              </td>
+              <td>
+                true | false
+              </td>
+              <td>
+                false
+              </td>
+            </tr>
           </tbody>
         </table>
         <p>

src/site/ja/xdoc/configuration.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 
-       Copyright 2009-2021 the original author or authors.
+       Copyright 2009-2022 the original author or authors.
 
        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
@@ -615,6 +615,20 @@ SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader, environ
                 false
               </td>
             </tr>
+            <tr>
+              <td>
+                argNameBasedConstructorAutoMapping
+              </td>
+              <td>
+                引数を受け取るコンストラクタに対して自動マッピングを適用する際、引数名に一致する列をマップ対象にします。<code>false</code> の場合は列の順序依存となります。 (導入されたバージョン: 3.5.10）
+              </td>
+              <td>
+                true | false
+              </td>
+              <td>
+                false
+              </td>
+            </tr>
           </tbody>
         </table>
         <p>

src/site/ko/xdoc/configuration.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 
-       Copyright 2009-2021 the original author or authors.
+       Copyright 2009-2022 the original author or authors.
 
        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
@@ -598,6 +598,20 @@ SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader, environ
                 false
               </td>
             </tr>
+            <tr>
+              <td>
+                argNameBasedConstructorAutoMapping
+              </td>
+              <td>
+                When applying constructor auto-mapping, argument name is used to search the column to map instead of relying on the column order. (Since 3.5.10)
+              </td>
+              <td>
+                true | false
+              </td>
+              <td>
+                false
+              </td>
+            </tr>
           </tbody>
         </table>
         <p>위 설정을 모두 사용한 setting 엘리먼트의 예제이다:</p>

src/site/xdoc/configuration.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 
-       Copyright 2009-2021 the original author or authors.
+       Copyright 2009-2022 the original author or authors.
 
        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
@@ -678,6 +678,20 @@ SqlSessionFactory factory =
                 false
               </td>
             </tr>
+            <tr>
+              <td>
+                argNameBasedConstructorAutoMapping
+              </td>
+              <td>
+                When applying constructor auto-mapping, argument name is used to search the column to map instead of relying on the column order. (Since 3.5.10)
+              </td>
+              <td>
+                true | false
+              </td>
+              <td>
+                false
+              </td>
+            </tr>
           </tbody>
         </table>
         <p>