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/**
 * Copyright 1999-2015 dangdang.com.
 * 
 * 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 com.github.javaclub.cdl.client.matrix.merger.common;

import java.math.BigDecimal;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Collection;

import lombok.AccessLevel;
import lombok.RequiredArgsConstructor;

import com.github.javaclub.cdl.client.matrix.exception.SMatrixJdbcException;
import com.github.javaclub.cdl.client.matrix.parser.result.merger.AggregationColumn;
import com.github.javaclub.cdl.client.matrix.parser.result.merger.GroupByColumn;
import com.github.javaclub.cdl.client.matrix.parser.result.merger.OrderByColumn;
import com.github.javaclub.cdl.client.matrix.parser.result.merger.OrderByColumn.OrderByType;
import com.google.common.base.Preconditions;

/**
 * 结果集处理工具类.
 * 
 * @author gaohongtao
 */
@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
public final class ResultSetUtil {

	/**
	 * 从结果集中提取结果值.
	 * 
	 * @param groupByColumn
	 *            分组列对象
	 * @param resultSet
	 *            目标结果集
	 * @return 结果对象
	 * @throws SQLException
	 */
	public static Object getValue(final GroupByColumn groupByColumn, final ResultSet resultSet) throws SQLException {
		Object result = getValue(groupByColumn.getAlias(), resultSet);
		Preconditions.checkNotNull(result);
		return result;
	}

	/**
	 * 从结果集中提取结果值.
	 * 
	 * @param orderByColumn
	 *            排序列对象
	 * @param resultSet
	 *            目标结果集
	 * @return 结果对象
	 * @throws SQLException
	 */
	public static Object getValue(final OrderByColumn orderByColumn, final ResultSet resultSet) throws SQLException {
		Object result = null;
		if (orderByColumn.getIndex().isPresent()) {
			result = resultSet.getObject(orderByColumn.getIndex().get());
		} else if (orderByColumn.getAlias().isPresent()) {
			result = getValue(orderByColumn.getAlias().get(), resultSet);
		} else if (orderByColumn.getName().isPresent()) {
			result = getValue(orderByColumn.getName().get(), resultSet);
		}
		Preconditions.checkNotNull(result);
		return result;
	}

	private static Object getValue(final String columnName, final ResultSet resultSet) throws SQLException {
		Object result = resultSet.getObject(columnName);
		if (null == result) {
			result = resultSet.getObject(columnName.toUpperCase());
		}
		if (null == result) {
			result = resultSet.getObject(columnName.toLowerCase());
		}
		return result;
	}

	/**
	 * 根据返回值类型返回特定类型的结果.
	 * 
	 * @param value
	 *            原始结果
	 * @param convertType
	 *            返回值类型
	 * @return 特定类型的返回结果
	 */
	public static Object convertValue(final Object value, final Class convertType) {
		if (null == value) {
			return convertNullValue(convertType);
		} else if (value instanceof Number) {
			return convertNumberValue(value, convertType);
		} else {
			if (String.class.equals(convertType)) {
				return value.toString();
			} else {
				return value;
			}
		}
	}

	private static Object convertNumberValue(final Object value, final Class convertType) {
		Number number = (Number) value;
		switch (convertType.getName()) {
		case "short":
			return number.shortValue();
		case "int":
			return number.intValue();
		case "long":
			return number.longValue();
		case "double":
			return number.doubleValue();
		case "float":
			return number.floatValue();
		case "java.math.BigDecimal":
			if (number instanceof BigDecimal) {
				return number;
			} else {
				return new BigDecimal(number.toString());
			}
		case "java.lang.Object":
			return value;
		case "java.lang.String":
			return value.toString();
		default:
			throw new SMatrixJdbcException("Unsupported data type:%s", convertType);
		}
	}

	private static Object convertNullValue(final Class convertType) {
		switch (convertType.getName()) {
		case "short":
			return (short) 0;
		case "int":
			return 0;
		case "long":
			return 0L;
		case "double":
			return 0D;
		case "float":
			return 0F;
		case "java.math.BigDecimal":
		case "java.lang.Object":
		case "java.lang.String":
			return null;
		default:
			throw new SMatrixJdbcException("Unsupported data type:%s", convertType);
		}
	}

	/**
	 * 根据排序类型比较大小.
	 * 
	 * @param thisValue
	 *            待比较的值
	 * @param otherValue
	 *            待比较的值
	 * @param orderByType
	 *            排序类型
	 * @return 负数，零和正数分别表示小于，等于和大于
	 */
	@SuppressWarnings({ "rawtypes", "unchecked" })
	public static int compareTo(final Comparable thisValue, final Comparable otherValue, final OrderByType orderByType) {
		return OrderByType.ASC == orderByType ? thisValue.compareTo(otherValue) : -thisValue.compareTo(otherValue);
	}

	/**
	 * 向聚合列的补列填充索引值.
	 * 
	 * @param resultSet
	 *            结果集对象
	 * @param aggregationColumns
	 *            聚合列集合
	 * @throws SQLException
	 *             SQL异常
	 */
	public static void fillIndexesForDerivedAggregationColumns(final ResultSet resultSet,
			final Collection aggregationColumns) throws SQLException {
		for (AggregationColumn aggregationColumn : aggregationColumns) {
			for (AggregationColumn derivedColumn : aggregationColumn.getDerivedColumns()) {
				derivedColumn.setIndex(resultSet.findColumn(derivedColumn.getAlias().get()));
			}
		}
	}
}