external/storm-jdbc/src/main/java/org/apache/storm/jdbc/mapper/SimpleJdbcLookupMapper.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.apache.storm.jdbc.mapper;


import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.ITuple;
import backtype.storm.tuple.Values;
import org.apache.commons.lang.Validate;
import org.apache.storm.jdbc.common.Column;

import java.util.ArrayList;
import java.util.List;

public class SimpleJdbcLookupMapper extends SimpleJdbcMapper implements JdbcLookupMapper {

    private Fields outputFields;

    public SimpleJdbcLookupMapper(Fields outputFields, List<Column> queryColumns) {
        super(queryColumns);

        Validate.notEmpty(outputFields.toList());
        this.outputFields = outputFields;
    }

    @Override
    public List<Values> toTuple(ITuple input, List<Column> columns) {
        Values values = new Values();

        for(String field : outputFields) {
            if(input.contains(field)) {
                values.add(input.getValueByField(field));
            } else {
                for(Column column : columns) {
                    if(column.getColumnName().equalsIgnoreCase(field)) {
                        values.add(column.getVal());
                    }
                }
            }
        }
        List<Values> result = new ArrayList<Values>();
        result.add(values);
        return result;
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(outputFields);
    }
}