Package org.apache.storm.redis.trident
Class WordCountLookupMapper
- java.lang.Object
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- org.apache.storm.redis.trident.WordCountLookupMapper
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- All Implemented Interfaces:
Serializable,RedisLookupMapper,RedisMapper,TupleMapper
public class WordCountLookupMapper extends Object implements RedisLookupMapper
- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description WordCountLookupMapper()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voiddeclareOutputFields(OutputFieldsDeclarer declarer)declare what are the fields that this code will output.RedisDataTypeDescriptiongetDataTypeDescription()Returns descriptor which defines data type.StringgetKeyFromTuple(ITuple tuple)Extracts key from tuple.StringgetValueFromTuple(ITuple tuple)Extracts value from tuple.List<Values>toTuple(ITuple input, Object value)Converts return value from Redis to a list of storm values that can be emitted.
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Method Detail
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toTuple
public List<Values> toTuple(ITuple input, Object value)
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
public void declareOutputFields(OutputFieldsDeclarer declarer)
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
public RedisDataTypeDescription getDataTypeDescription()
Description copied from interface:RedisMapperReturns descriptor which defines data type.- Specified by:
getDataTypeDescriptionin interfaceRedisMapper- Returns:
- data type descriptor
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getKeyFromTuple
public String getKeyFromTuple(ITuple tuple)
Description copied from interface:TupleMapperExtracts key from tuple.- Specified by:
getKeyFromTuplein interfaceTupleMapper- Parameters:
tuple- source tuple- Returns:
- key
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getValueFromTuple
public String getValueFromTuple(ITuple tuple)
Description copied from interface:TupleMapperExtracts value from tuple.- Specified by:
getValueFromTuplein interfaceTupleMapper- Parameters:
tuple- source tuple- Returns:
- value
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