Performed Refactoring for design smells and code smells in the repo

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

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2023 the original author or authors.
+ *    Copyright 2009-2024 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.
@@ -18,11 +18,9 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
-import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.ibatis.builder.annotation.MapperAnnotationBuilder;
-import org.apache.ibatis.io.ResolverUtil;
 import org.apache.ibatis.session.Configuration;
 import org.apache.ibatis.session.SqlSession;
 
@@ -65,9 +63,6 @@ public <T> void addMapper(Class<T> type) {
       boolean loadCompleted = false;
       try {
         knownMappers.put(type, new MapperProxyFactory<>(type));
-        // It's important that the type is added before the parser is run
-        // otherwise the binding may automatically be attempted by the
-        // mapper parser. If the type is already known, it won't try.
         MapperAnnotationBuilder parser = new MapperAnnotationBuilder(config, type);
         parser.parse();
         loadCompleted = true;
@@ -79,46 +74,15 @@ public <T> void addMapper(Class<T> type) {
     }
   }
 
-  /**
-   * Gets the mappers.
-   *
-   * @return the mappers
-   *
-   * @since 3.2.2
-   */
   public Collection<Class<?>> getMappers() {
     return Collections.unmodifiableCollection(knownMappers.keySet());
   }
 
-  /**
-   * Adds the mappers.
-   *
-   * @param packageName
-   *          the package name
-   * @param superType
-   *          the super type
-   *
-   * @since 3.2.2
-   */
   public void addMappers(String packageName, Class<?> superType) {
-    ResolverUtil<Class<?>> resolverUtil = new ResolverUtil<>();
-    resolverUtil.find(new ResolverUtil.IsA(superType), packageName);
-    Set<Class<? extends Class<?>>> mapperSet = resolverUtil.getClasses();
-    for (Class<?> mapperClass : mapperSet) {
-      addMapper(mapperClass);
-    }
+    MapperRegistryHelper.addMappers(this, packageName, superType);
   }
 
-  /**
-   * Adds the mappers.
-   *
-   * @param packageName
-   *          the package name
-   *
-   * @since 3.2.2
-   */
   public void addMappers(String packageName) {
-    addMappers(packageName, Object.class);
+    MapperRegistryHelper.addMappers(this, packageName);
   }
-
 }

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

@@ -0,0 +1,35 @@
+/*
+ *    Copyright 2009-2024 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.binding;
+
+import java.util.Set;
+
+import org.apache.ibatis.io.ResolverUtil;
+
+public class MapperRegistryHelper {
+  public static void addMappers(MapperRegistry registry, String packageName, Class<?> superType) {
+    ResolverUtil<Class<?>> resolverUtil = new ResolverUtil<>();
+    resolverUtil.find(new ResolverUtil.IsA(superType), packageName);
+    Set<Class<? extends Class<?>>> mapperSet = resolverUtil.getClasses();
+    for (Class<?> mapperClass : mapperSet) {
+      registry.addMapper(mapperClass);
+    }
+  }
+
+  public static void addMappers(MapperRegistry registry, String packageName) {
+    addMappers(registry, packageName, Object.class);
+  }
+}

src/main/java/org/apache/ibatis/mapping/ResultMap.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2023 the original author or authors.
+ *    Copyright 2009-2024 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.
@@ -206,6 +206,13 @@ private List<String> getArgNames(Constructor<?> constructor) {
     }
   }
 
+  public static void validateNestedQueryAndResultMap(ResultMapping resultMapping) {
+    if (resultMapping.getNestedQueryId() != null && resultMapping.getNestedResultMapId() != null) {
+      throw new IllegalStateException(
+          "Cannot define both nestedQueryId and nestedResultMapId in property " + resultMapping.getProperty());
+    }
+  }
+
   public String getId() {
     return id;
   }

src/main/java/org/apache/ibatis/mapping/ResultMapping.java

@@ -15,6 +15,8 @@
  */
 package org.apache.ibatis.mapping;
 
+import static org.apache.ibatis.mapping.ResultMap.validateNestedQueryAndResultMap;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -142,19 +144,12 @@ public ResultMapping build() {
     }
 
     private void validate() {
-      validateNestedQueryAndResultMap();
+      validateNestedQueryAndResultMap(resultMapping);
       validateTypeHandler();
       validateColumn();
       validateResultSet();
     }
 
-    private void validateNestedQueryAndResultMap() {
-      if (resultMapping.nestedQueryId != null && resultMapping.nestedResultMapId != null) {
-        throw new IllegalStateException(
-            "Cannot define both nestedQueryId and nestedResultMapId in property " + resultMapping.property);
-      }
-    }
-
     private void validateTypeHandler() {
       if (resultMapping.nestedQueryId == null && resultMapping.nestedResultMapId == null
           && resultMapping.typeHandler == null) {