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

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and 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.TupleMapper

      `getKeyFromTuple, getValueFromTuple`

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

      `getDataTypeDescription`

- - ### Method Detail

    - #### 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

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