Class: Norikra::UDF::SingleRow

Inherits:
Object
  • Object
show all
Defined in:
lib/norikra/udf.rb

Overview

esper-4.9.0/esper/doc/reference/html/extension.html#custom-singlerow-function <esper-configuration

<plugin-singlerow-function name="getDate"
  function-class="mycompany.DateUtil" function-method="parseDate"
  value-cache="enabled"
  filter-optimizable="disabled"
  rethrow-exceptions="disabled" />

</esper-configuration>

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.init ⇒ Object 



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# File 'lib/norikra/udf.rb', line 18

def self.init
  true
end

Instance Method Details

#class_name ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/norikra/udf.rb', line 31

def class_name
  raise NotImplementedError
end

#definition ⇒ Object 



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# File 'lib/norikra/udf.rb', line 22

def definition
  [self.function_name, self.class_name, self.method_name]
end

#filter_optimizable ⇒ Object

17.3.4. Single-Row Functions in Filter Predicate Expressions Your EPL may use plug-in single row functions among the predicate expressions as part of the filters in a stream or pattern. For example, the EPL below uses the function computeHash as part of a predicate expression:

select * from MyEvent(computeHash(field) = 100)

When you have many EPL statements or many context partitions that refer to the same function, event type and parameters in a predicate expression, the engine may optimize evaluation: The function gets evaluated only once per event.

While the optimization is enabled by default for all plug-in single row functions, you can also disable the optimization for a specific single-row function. By disabling the optimization for a single-row function the engine may use less memory to identify reusable function footprints but may cause the engine to evaluate each function more frequently then necessary.



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# File 'lib/norikra/udf.rb', line 65

def filter_optimizable
  true
end

#function_name ⇒ Object

UDF function name in queries

Raises:

  • (NotImplementedError) 


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# File 'lib/norikra/udf.rb', line 27

def function_name
  raise NotImplementedError
end

#method_name ⇒ Object 



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# File 'lib/norikra/udf.rb', line 35

def method_name
  function_name
end

#rethrow_exceptions ⇒ Object

17.3.7. Exception Handling By default the engine logs any exceptions thrown by the single row function and returns a null value. To have exceptions be re-thrown instead, which makes exceptions visible to any registered exception handler, please configure as discussed herein.



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# File 'lib/norikra/udf.rb', line 73

def rethrow_exceptions
  false
end

#value_cache ⇒ Object

17.3.3. Value Cache When a single-row function receives parameters that are all constant values or expressions that themselves receive only constant values, Esper can pre-evaluate the result of the single-row function at time of statement creation. By default, Esper does not pre-evaluate the single-row function unless you configure the value cache as enabled.



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# File 'lib/norikra/udf.rb', line 45

def value_cache
  false
end