/*
    *    Copyright 2009-2021 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
    *
    *       http://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.executor;
  
  import java.lang.reflect.Array;
  import java.util.List;
  
  import org.apache.ibatis.reflection.MetaObject;
  import org.apache.ibatis.reflection.factory.ObjectFactory;
  import org.apache.ibatis.session.Configuration;
  
  /**
   * @author Andrew Gustafson
   */
  public class ResultExtractor {
    private final Configuration configuration;
    private final ObjectFactory objectFactory;
  
    public ResultExtractor(Configuration configuration, ObjectFactory objectFactory) {
      this.configuration = configuration;
      this.objectFactory = objectFactory;
    }
  
    public Object extractObjectFromList(List<Object> list, Class<?> targetType) {
      Object value = null;
      if (targetType != null && targetType.isAssignableFrom(list.getClass())) {
        value = list;
      } else if (targetType != null && objectFactory.isCollection(targetType)) {
        value = objectFactory.create(targetType);
        MetaObject metaObject = configuration.newMetaObject(value);
        metaObject.addAll(list);
      } else if (targetType != null && targetType.isArray()) {
        Class<?> arrayComponentType = targetType.getComponentType();
        Object array = Array.newInstance(arrayComponentType, list.size());
        if (arrayComponentType.isPrimitive()) {
          for (int i = 0; i < list.size(); i++) {
            Array.set(array, i, list.get(i));
          }
          value = array;
        } else {
          value = list.toArray((Object[])array);
        }
      } else {
        if (list != null && list.size() > 1) {
          throw new ExecutorException("Statement returned more than one row, where no more than one was expected.");
        } else if (list != null && list.size() == 1) {
          value = list.get(0);
        }
      }
      return value;
    }
  }