add MapValue annotation

src/main/java/org/apache/ibatis/annotations/MapValue.java

@@ -0,0 +1,27 @@
+/*
+ *    Copyright 2009-2023 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.
+ *    You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.annotations;
+
+import java.lang.annotation.*;
+
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.METHOD)
+public @interface MapValue {
+
+  String value();
+
+}

src/main/java/org/apache/ibatis/binding/MapperMethod.java

@@ -26,6 +26,7 @@
 
 import org.apache.ibatis.annotations.Flush;
 import org.apache.ibatis.annotations.MapKey;
+import org.apache.ibatis.annotations.MapValue;
 import org.apache.ibatis.cursor.Cursor;
 import org.apache.ibatis.mapping.MappedStatement;
 import org.apache.ibatis.mapping.SqlCommandType;
@@ -193,9 +194,9 @@ private <K, V> Map<K, V> executeForMap(SqlSession sqlSession, Object[] args) {
     Object param = method.convertArgsToSqlCommandParam(args);
     if (method.hasRowBounds()) {
       RowBounds rowBounds = method.extractRowBounds(args);
-      result = sqlSession.selectMap(command.getName(), param, method.getMapKey(), rowBounds);
+      result = sqlSession.selectMap(command.getName(), param, method.getMapKey(), method.getMapValue(), rowBounds);
     } else {
-      result = sqlSession.selectMap(command.getName(), param, method.getMapKey());
+      result = sqlSession.selectMap(command.getName(), param, method.getMapKey(), method.getMapValue());
     }
     return result;
   }
@@ -277,6 +278,7 @@ public static class MethodSignature {
     private final boolean returnsOptional;
     private final Class<?> returnType;
     private final String mapKey;
+    private final String mapValue;
     private final Integer resultHandlerIndex;
     private final Integer rowBoundsIndex;
     private final ParamNameResolver paramNameResolver;
@@ -295,6 +297,7 @@ public MethodSignature(Configuration configuration, Class<?> mapperInterface, Me
       this.returnsCursor = Cursor.class.equals(this.returnType);
       this.returnsOptional = Optional.class.equals(this.returnType);
       this.mapKey = getMapKey(method);
+      this.mapValue = getMapValue(method);
       this.returnsMap = this.mapKey != null;
       this.rowBoundsIndex = getUniqueParamIndex(method, RowBounds.class);
       this.resultHandlerIndex = getUniqueParamIndex(method, ResultHandler.class);
@@ -371,6 +374,10 @@ public String getMapKey() {
       return mapKey;
     }
 
+    public String getMapValue() {
+      return mapValue;
+    }
+
     private String getMapKey(Method method) {
       String mapKey = null;
       if (Map.class.isAssignableFrom(method.getReturnType())) {
@@ -381,6 +388,18 @@ private String getMapKey(Method method) {
       }
       return mapKey;
     }
+
+    private String getMapValue(Method method) {
+      String mapValue = null;
+      if (Map.class.isAssignableFrom(method.getReturnType())) {
+        final MapValue annotation = method.getAnnotation(MapValue.class);
+        if (annotation != null) {
+          mapValue = annotation.value();
+        }
+      }
+      return mapValue;
+    }
+
   }
 
 }

src/main/java/org/apache/ibatis/executor/result/DefaultMapResultHandler.java

@@ -31,18 +31,20 @@ public class DefaultMapResultHandler<K, V> implements ResultHandler<V> {
 
   private final Map<K, V> mappedResults;
   private final String mapKey;
+  private final String mapValue;
   private final ObjectFactory objectFactory;
   private final ObjectWrapperFactory objectWrapperFactory;
   private final ReflectorFactory reflectorFactory;
 
   @SuppressWarnings("unchecked")
-  public DefaultMapResultHandler(String mapKey, ObjectFactory objectFactory, ObjectWrapperFactory objectWrapperFactory,
-      ReflectorFactory reflectorFactory) {
+  public DefaultMapResultHandler(String mapKey, String mapValue, ObjectFactory objectFactory,
+      ObjectWrapperFactory objectWrapperFactory, ReflectorFactory reflectorFactory) {
     this.objectFactory = objectFactory;
     this.objectWrapperFactory = objectWrapperFactory;
     this.reflectorFactory = reflectorFactory;
     this.mappedResults = objectFactory.create(Map.class);
     this.mapKey = mapKey;
+    this.mapValue = mapValue;
   }
 
   @Override
@@ -51,7 +53,7 @@ public void handleResult(ResultContext<? extends V> context) {
     final MetaObject mo = MetaObject.forObject(value, objectFactory, objectWrapperFactory, reflectorFactory);
     // TODO is that assignment always true?
     final K key = (K) mo.getValue(mapKey);
-    mappedResults.put(key, value);
+    mappedResults.put(key, ((V) (mapValue == null ? value : mo.getValue(mapValue))));
   }
 
   public Map<K, V> getMappedResults() {

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

@@ -156,6 +156,50 @@ public interface SqlSession extends Closeable {
    */
   <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds);
 
+  /**
+   * The selectMap is a special case in that it is designed to convert a list of results into a Map based on one of the
+   * properties in the resulting objects.
+   *
+   * @param <K>
+   *          the returned Map keys type
+   * @param <V>
+   *          the returned Map values type
+   * @param statement
+   *          Unique identifier matching the statement to use.
+   * @param parameter
+   *          A parameter object to pass to the statement.
+   * @param mapKey
+   *          The property to use as key for each value in the list.
+   * @param mapValue
+   *          The property to use as value for each value in the list.
+   *
+   * @return Map containing key pair data.
+   */
+  <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, String mapValue);
+
+  /**
+   * The selectMap is a special case in that it is designed to convert a list of results into a Map based on one of the
+   * properties in the resulting objects.
+   *
+   * @param <K>
+   *          the returned Map keys type
+   * @param <V>
+   *          the returned Map values type
+   * @param statement
+   *          Unique identifier matching the statement to use.
+   * @param parameter
+   *          A parameter object to pass to the statement.
+   * @param mapKey
+   *          The property to use as key for each value in the list.
+   * @param mapValue
+   *          The property to use as value for each value in the list.
+   * @param rowBounds
+   *          Bounds to limit object retrieval
+   *
+   * @return Map containing key pair data.
+   */
+  <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, String mapValue, RowBounds rowBounds);
+
   /**
    * A Cursor offers the same results as a List, except it fetches data lazily using an Iterator.
    *

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

@@ -179,6 +179,16 @@ public <K, V> Map<K, V> selectMap(String statement, Object parameter, String map
     return sqlSessionProxy.selectMap(statement, parameter, mapKey, rowBounds);
   }
 
+  public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, String mapValue) {
+    return sqlSessionProxy.selectMap(statement, parameter, mapKey, mapValue);
+  }
+
+  @Override
+  public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, String mapValue,
+      RowBounds rowBounds) {
+    return sqlSessionProxy.selectMap(statement, parameter, mapKey, rowBounds);
+  }
+
   @Override
   public <T> Cursor<T> selectCursor(String statement) {
     return sqlSessionProxy.selectCursor(statement);

src/main/java/org/apache/ibatis/session/defaults/DefaultSqlSession.java

@@ -96,8 +96,19 @@ public <K, V> Map<K, V> selectMap(String statement, Object parameter, String map
 
   @Override
   public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds) {
+    return this.selectMap(statement, parameter, mapKey, null, rowBounds);
+  }
+
+  @Override
+  public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, String mapValue) {
+    return this.selectMap(statement, parameter, mapKey, mapValue, RowBounds.DEFAULT);
+  }
+
+  @Override
+  public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, String mapValue,
+      RowBounds rowBounds) {
     final List<? extends V> list = selectList(statement, parameter, rowBounds);
-    final DefaultMapResultHandler<K, V> mapResultHandler = new DefaultMapResultHandler<>(mapKey,
+    final DefaultMapResultHandler<K, V> mapResultHandler = new DefaultMapResultHandler<>(mapKey, mapValue,
         configuration.getObjectFactory(), configuration.getObjectWrapperFactory(), configuration.getReflectorFactory());
     final DefaultResultContext<V> context = new DefaultResultContext<>();
     for (V o : list) {

src/test/java/org/apache/ibatis/session/SqlSessionTest.java

@@ -53,6 +53,7 @@
 import org.apache.ibatis.mapping.SqlCommandType;
 import org.apache.ibatis.mapping.SqlSource;
 import org.apache.ibatis.session.defaults.DefaultSqlSessionFactory;
+import org.apache.ibatis.submitted.mapkey_value.NoticeMapper;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -180,6 +181,18 @@ void shouldSelectAllAuthorsAsMap() {
     }
   }
 
+  @Test
+  public void shouldGroupStatusAsMap() {
+    try (SqlSession sqlSession = sqlMapper.openSession()) {
+      NoticeMapper mapper = sqlSession.getMapper(NoticeMapper.class);
+      Map<Integer, Integer> statusCount = mapper.groupStatus();
+      assertEquals(2, statusCount.size());
+      assertEquals(statusCount.get(1), 3);
+      assertEquals(statusCount.get(2), 4);
+
+    }
+  }
+
   @Test
   void shouldSelectCountOfPosts() {
     try (SqlSession session = sqlMapper.openSession()) {

src/test/java/org/apache/ibatis/submitted/mapkey_value/NoticeMapper.java

@@ -0,0 +1,28 @@
+/*
+ *    Copyright 2009-2023 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.
+ *    You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.submitted.mapkey_value;
+
+import java.util.Map;
+
+import org.apache.ibatis.annotations.MapKey;
+import org.apache.ibatis.annotations.MapValue;
+
+public interface NoticeMapper {
+
+  @MapKey("status")
+  @MapValue("count")
+  Map<Integer, Integer> groupStatus();
+}

src/test/resources/org/apache/ibatis/builder/MapperConfig.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" ?>
 <!--
 
-       Copyright 2009-2022 the original author or authors.
+       Copyright 2009-2023 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.
@@ -77,6 +77,7 @@
     <mapper resource="org/apache/ibatis/builder/CachedAuthorMapper.xml"/>
     <mapper resource="org/apache/ibatis/builder/PostMapper.xml"/>
     <mapper resource="org/apache/ibatis/builder/NestedBlogMapper.xml"/>
+    <mapper resource="org/apache/ibatis/builder/NoticeMapper.xml"/>
   </mappers>
 
 </configuration>

src/test/resources/org/apache/ibatis/builder/NoticeMapper.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+
+       Copyright 2009-2023 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.
+       You may obtain a copy of the License at
+
+          https://www.apache.org/licenses/LICENSE-2.0
+
+       Unless required by applicable law or agreed to in writing, software
+       distributed under the License is distributed on an "AS IS" BASIS,
+       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+       See the License for the specific language governing permissions and
+       limitations under the License.
+
+-->
+<!DOCTYPE mapper
+    PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
+    "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
+
+<mapper namespace="org.apache.ibatis.submitted.mapkey_value.NoticeMapper">
+
+
+  <resultMap id="groupStatusMap" type="hashmap">
+    <result column="count" javaType="Integer" property="count"/>
+    <result column="status" javaType="Integer" property="status"/>
+  </resultMap>
+
+
+  <select id="groupStatus" resultMap="groupStatusMap">
+  select count(*) as count , status
+    from notice group by status
+  </select>
+
+
+</mapper>

src/test/resources/org/apache/ibatis/databases/blog/blog-derby-dataload.sql

@@ -1,5 +1,5 @@
 --
---    Copyright 2009-2022 the original author or authors.
+--    Copyright 2009-2023 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.
@@ -49,10 +49,18 @@ INSERT INTO comment (id,post_id,name,comment) VALUES (3,3,'rider','I prefer moto
 --  4  5   6  7
 
 INSERT INTO node (id, parent_id) VALUES (1,null);
-INSERT INTO node (id, parent_id) VALUES (2,1); 
+INSERT INTO node (id, parent_id) VALUES (2,1);
 INSERT INTO node (id, parent_id) VALUES (3,1);
 INSERT INTO node (id, parent_id) VALUES (4,2);
 INSERT INTO node (id, parent_id) VALUES (5,2);
 INSERT INTO node (id, parent_id) VALUES (6,3);
 INSERT INTO node (id, parent_id) VALUES (7,3);
 
+
+INSERT INTO notice (id, status) VALUES (1,1);
+INSERT INTO notice (id, status) VALUES (2,2);
+INSERT INTO notice (id, status) VALUES (3,1);
+INSERT INTO notice (id, status) VALUES (4,2);
+INSERT INTO notice (id, status) VALUES (5,1);
+INSERT INTO notice (id, status) VALUES (6,2);
+INSERT INTO notice (id, status) VALUES (7,2);

src/test/resources/org/apache/ibatis/databases/blog/blog-derby-schema.sql

@@ -1,5 +1,5 @@
 --
---    Copyright 2009-2022 the original author or authors.
+--    Copyright 2009-2023 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.
@@ -80,6 +80,12 @@ parent_id INT,
 PRIMARY KEY(id)
 );
 
+CREATE TABLE notice (
+id  INT NOT NULL,
+status INT NOT NULL,
+PRIMARY KEY(id)
+);
+
 CREATE PROCEDURE selectTwoSetsOfAuthors(DP1 INTEGER, DP2 INTEGER)
 PARAMETER STYLE JAVA
 LANGUAGE JAVA