ObjectResultSetExtractor.java

/*
 * Copyright 2014 mango.jfaster.org
 *
 * The Mango Project licenses this file to you 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.jfaster.mango.jdbc;

import org.jfaster.mango.mapper.MappingException;
import org.jfaster.mango.mapper.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * @author ash
 */
public class ObjectResultSetExtractor<T> implements ResultSetExtractor<T> {

  private final RowMapper<T> rowMapper;

  public ObjectResultSetExtractor(RowMapper<T> rowMapper) {
    this.rowMapper = rowMapper;
  }

  @Override
  public T extractData(ResultSet rs) throws SQLException {
    Class<T> mappedClass = rowMapper.getMappedClass();
    if (!mappedClass.isPrimitive()) {
      return rs.next() ? rowMapper.mapRow(rs, 0) : null;
    }

    // 原生类型
    if (!rs.next()) {
      throw new MappingException("no data, can't cast null to primitive type " + mappedClass);
    }
    T r = rowMapper.mapRow(rs, 0);
    if (r == null) {
      throw new MappingException("data is null, can't cast null to primitive type " + mappedClass);
    }
    return r;
  }

}