/*
* Copyright 2014 mango.concurrent.cc
*
* 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 cc.concurrent.mango.jdbc;
import cc.concurrent.mango.exception.IncorrectResultSetColumnCountException;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
/**
* 单列RowMapper
*
* @author ash
*/
public class SingleColumnRowMapper<T> implements RowMapper<T> {
private Class<T> mappedClass;
public SingleColumnRowMapper(Class<T> mappedClass) {
this.mappedClass = mappedClass;
}
@SuppressWarnings("unchecked")
public T mapRow(ResultSet rs, int rowNum) throws SQLException {
// 验证列数
ResultSetMetaData rsmd = rs.getMetaData();
int nrOfColumns = rsmd.getColumnCount();
if (nrOfColumns != 1) {
throw new IncorrectResultSetColumnCountException("incorrect column count, expected 1 but " + nrOfColumns);
}
Object result = getColumnValue(rs, 1, this.mappedClass);
return (T) result;
}
@Override
public Class<T> getMappedClass() {
return mappedClass;
}
protected Object getColumnValue(ResultSet rs, int index, Class requiredType) throws SQLException {
return JdbcUtils.getResultSetValue(rs, index, requiredType);
}
}