com.iksgmbh.sql.pojomemodb.sqlparser.helper.OrderConditionParser.java Source code

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Here is the source code for com.iksgmbh.sql.pojomemodb.sqlparser.helper.OrderConditionParser.java

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/*
 * Copyright 2016 IKS Gesellschaft fuer Informations- und Kommunikationssysteme mbH
 * 
 * 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.iksgmbh.sql.pojomemodb.sqlparser.helper;

import com.iksgmbh.sql.pojomemodb.SQLKeyWords;
import com.iksgmbh.sql.pojomemodb.dataobjects.temporal.OrderCondition;
import com.iksgmbh.sql.pojomemodb.sqlparser.SqlPojoMemoParser;
import com.iksgmbh.sql.pojomemodb.utils.StringParseUtil;
import com.iksgmbh.sql.pojomemodb.utils.StringParseUtil.InterimParseResult;
import org.apache.commons.lang3.StringUtils;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * Parses order conditions.
 *
 * @author Reik Oberrath
 */
public class OrderConditionParser extends SqlPojoMemoParser {
    public static List<OrderCondition> doYourJob(final String orderClause) throws SQLException {
        return new OrderConditionParser().parseConditions(orderClause);
    }

    // TODO mehere conditions mit asc, desc testen
    public List<OrderCondition> parseConditions(final String orderClause) throws SQLException {
        if (StringUtils.isEmpty(orderClause))
            throw new SQLException("No column defined for order by!");

        String unparsedRest = orderClause;
        if (unparsedRest.startsWith("(")) {
            unparsedRest = StringParseUtil.removeSurroundingPrefixAndPostFix(unparsedRest, "(", ")");
        }

        final List<OrderCondition> toReturn = new ArrayList<OrderCondition>();
        InterimParseResult parseResult = null;
        while (unparsedRest.length() > 0) {
            parseResult = StringParseUtil.parseNextValue(unparsedRest, StringParseUtil.COMMA);
            toReturn.add(parseOrderCondition(parseResult.parsedValue));
            unparsedRest = parseResult.unparsedRest;
        }

        return toReturn;
    }

    private OrderCondition parseOrderCondition(final String input) throws SQLException {
        final InterimParseResult parseResult = StringParseUtil.parseNextValue(input, StringParseUtil.SPACE);
        final String columnName = parseResult.parsedValue;

        String direction = SQLKeyWords.ASC;
        if (parseResult.unparsedRest.length() > 0) {
            direction = parseResult.unparsedRest;
        }

        return new OrderCondition(columnName, direction);
    }

    @Override
    protected String getSqlCommand() {
        return null; // not needed for an helper of the helper classes 
    }

}