Package org.apache.storm.redis.common.mapper

# Interface RedisLookupMapper

All Superinterfaces:
  `RedisMapper`, `Serializable`, `TupleMapper`

All Known Implementing Classes:
  `WordCountLookupMapper`

public interface RedisLookupMapper extends TupleMapper, RedisMapper
RedisLookupMapper is for defining spec. which is used for querying value from Redis and converting response to tuple.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `declareOutputFields(OutputFieldsDeclarer declarer)`
  declare what are the fields that this code will output.
  `List<Values>`
  `toTuple(ITuple input, Object value)`
  Converts return value from Redis to a list of storm values that can be emitted.

  ### Methods inherited from interface org.apache.storm.redis.common.mapper.RedisMapper

  `getDataTypeDescription`

  ### Methods inherited from interface org.apache.storm.redis.common.mapper.TupleMapper

  `getKeyFromTuple, getValueFromTuple`

- ## Method Details

  - ### toTuple

    List<Values> toTuple(ITuple input, Object value)
    Converts return value from Redis to a list of storm values that can be emitted.
    Parameters:
      `input` - the input tuple.
      `value` - Redis query response value. Can be String, Boolean, Long regarding of data type.
    Returns:
      a List of storm values that can be emitted. Each item in list is emitted as an output tuple.

  - ### declareOutputFields

    void declareOutputFields(OutputFieldsDeclarer declarer)
    declare what are the fields that this code will output.
    Parameters:
      `declarer` - OutputFieldsDeclarer