com.ibatis.sqlmap.engine.mapping.result.loader.ResultLoader Maven / Gradle / Ivy

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/*
 * Copyright 2004-2022 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.
 * 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 com.ibatis.sqlmap.engine.mapping.result.loader;

import com.ibatis.sqlmap.engine.impl.SqlMapClientImpl;
import com.ibatis.sqlmap.engine.type.DomCollectionTypeMarker;

import java.lang.reflect.Array;
import java.sql.SQLException;
import java.util.*;

/**
 * Class to load results into objects.
 */
public class ResultLoader {

  /**
   * Instantiates a new result loader.
   */
  private ResultLoader() {
  }

  /**
   * Loads a result lazily.
   *
   * @param client
   *          - the client creating the object
   * @param statementName
   *          - the name of the statement to be used
   * @param parameterObject
   *          - the parameters for the statement
   * @param targetType
   *          - the target type of the result
   *
   * @return the loaded result
   *
   * @throws SQLException
   *           the SQL exception
   */
  public static Object loadResult(SqlMapClientImpl client, String statementName, Object parameterObject,
      Class targetType) throws SQLException {
    Object value = null;

    if (client.isLazyLoadingEnabled()) {
      if (client.isEnhancementEnabled()) {
        EnhancedLazyResultLoader lazy = new EnhancedLazyResultLoader(client, statementName, parameterObject,
            targetType);
        value = lazy.loadResult();
      } else {
        LazyResultLoader lazy = new LazyResultLoader(client, statementName, parameterObject, targetType);
        value = lazy.loadResult();
      }
    } else {
      value = getResult(client, statementName, parameterObject, targetType);
    }

    return value;
  }

  /**
   * Gets the result.
   *
   * @param client
   *          the client
   * @param statementName
   *          the statement name
   * @param parameterObject
   *          the parameter object
   * @param targetType
   *          the target type
   *
   * @return the result
   *
   * @throws SQLException
   *           the SQL exception
   */
  protected static Object getResult(SqlMapClientImpl client, String statementName, Object parameterObject,
      Class targetType) throws SQLException {
    Object value = null;
    if (DomCollectionTypeMarker.class.isAssignableFrom(targetType)) {
      value = client.queryForList(statementName, parameterObject);
    } else if (Set.class.isAssignableFrom(targetType)) {
      value = new HashSet(client.queryForList(statementName, parameterObject));
    } else if (Collection.class.isAssignableFrom(targetType)) {
      value = client.queryForList(statementName, parameterObject);
    } else if (targetType.isArray()) {
      List list = client.queryForList(statementName, parameterObject);
      value = listToArray(list, targetType.getComponentType());
    } else {
      value = client.queryForObject(statementName, parameterObject);
    }
    return value;
  }

  /**
   * List to array.
   *
   * @param list
   *          the list
   * @param type
   *          the type
   *
   * @return the object
   */
  private static Object listToArray(List list, Class type) {
    Object array = java.lang.reflect.Array.newInstance(type, list.size());
    if (type.isPrimitive()) {
      Iterator iter = list.iterator();
      int index = 0;
      while (iter.hasNext()) {
        Array.set(array, index++, iter.next());
      }
    } else {
      array = list.toArray((Object[]) array);
    }
    return array;

  }

}