/*
* Copyright 1999-2015 dangdang.com.
* <p>
* 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.
* </p>
*/
package com.dangdang.ddframe.rdb.sharding.merger.resultset.memory.row;
import com.dangdang.ddframe.rdb.sharding.merger.util.ResultSetUtil;
import com.dangdang.ddframe.rdb.sharding.parser.result.merger.OrderByColumn;
import com.google.common.base.Preconditions;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
/**
* 具有排序功能的数据行对象.
*
* @author gaohongtao
* @author zhangliang
*/
public final class OrderByResultSetRow extends AbstractResultSetRow implements Comparable<OrderByResultSetRow> {
private final List<OrderByColumn> orderByColumns;
private final List<Comparable<?>> orderByValues;
public OrderByResultSetRow(final ResultSet resultSet, final List<OrderByColumn> orderByColumns) throws SQLException {
super(resultSet);
this.orderByColumns = orderByColumns;
orderByValues = loadOrderByValues();
}
private List<Comparable<?>> loadOrderByValues() {
List<Comparable<?>> result = new ArrayList<>(orderByColumns.size());
for (OrderByColumn each : orderByColumns) {
Object value = getCell(each.getColumnIndex());
Preconditions.checkState(value instanceof Comparable, "Sharding-JDBC: order by value must extends Comparable");
result.add((Comparable<?>) value);
}
return result;
}
@Override
public int compareTo(final OrderByResultSetRow otherOrderByValue) {
for (int i = 0; i < orderByColumns.size(); i++) {
OrderByColumn thisOrderByColumn = orderByColumns.get(i);
int result = ResultSetUtil.compareTo(orderByValues.get(i), otherOrderByValue.orderByValues.get(i), thisOrderByColumn.getOrderByType());
if (0 != result) {
return result;
}
}
return 0;
}
@Override
public String toString() {
return String.format("Order by columns value is %s", orderByValues);
}
}