Package org.apache.storm.redis.trident
Class WordCountLookupMapper
java.lang.Object
org.apache.storm.redis.trident.WordCountLookupMapper
- All Implemented Interfaces:
Serializable,RedisLookupMapper,RedisMapper,TupleMapper
- See Also:
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoiddeclareOutputFields(OutputFieldsDeclarer declarer) declare what are the fields that this code will output.Returns descriptor which defines data type.getKeyFromTuple(ITuple tuple) Extracts key from tuple.getValueFromTuple(ITuple tuple) Extracts value from tuple.Converts return value from Redis to a list of storm values that can be emitted.
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Constructor Details
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WordCountLookupMapper
public WordCountLookupMapper()
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Method Details
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toTuple
Description copied from interface:RedisLookupMapperConverts return value from Redis to a list of storm values that can be emitted.- Specified by:
toTuplein interfaceRedisLookupMapper- 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.
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declareOutputFields
Description copied from interface:RedisLookupMapperdeclare what are the fields that this code will output.- Specified by:
declareOutputFieldsin interfaceRedisLookupMapper- Parameters:
declarer- OutputFieldsDeclarer
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getDataTypeDescription
Description copied from interface:RedisMapperReturns descriptor which defines data type.- Specified by:
getDataTypeDescriptionin interfaceRedisMapper- Returns:
- data type descriptor
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getKeyFromTuple
Description copied from interface:TupleMapperExtracts key from tuple.- Specified by:
getKeyFromTuplein interfaceTupleMapper- Parameters:
tuple- source tuple- Returns:
- key
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getValueFromTuple
Description copied from interface:TupleMapperExtracts value from tuple.- Specified by:
getValueFromTuplein interfaceTupleMapper- Parameters:
tuple- source tuple- Returns:
- value
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