Class: Turbine::Pipeline::Filter

Inherits:
Segment
  • Object
show all
Includes:
Trace::Transparent
Defined in:
lib/turbine/pipeline/filter.rb

Overview

Emits only those values in the pipeline which satisfy the filter. Filter is to Pipeline as select is to Enumerable.

Filter.new { |x| firewall.permitted?(x) }

Direct Known Subclasses

JournalFilter, Unique

Instance Attribute Summary

Attributes inherited from Segment

#source

Instance Method Summary collapse

Methods included from Trace::Transparent

#trace

Methods inherited from Segment

#append, #each, #inspect, #rewind, #to_s, #trace, #tracing=

Constructor Details

#initialize(&block) ⇒ Filter

Public: Creates a new Filter segment.

You may opt to use the Filter class directly, passing a block when initializing which is used to control which values are emitted. Alternatively, provide no block and use a subclass with a custom filter method.

Without a filter block, all elements are emitted.

block - An optional block used to select which values are emitted by

the filter.

Returns a Filter.



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# File 'lib/turbine/pipeline/filter.rb', line 24

def initialize(&block)
  @filter = (block || method(:filter))
  super()
end

Instance Method Details

#next ⇒ Object

Public: Runs the pipeline continuously until a value which matches the filter is found, then that value is emitted.

Returns an object.



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# File 'lib/turbine/pipeline/filter.rb', line 33

def next
  # Discard non-matching values.
  nil until (value = input) && @filter.call(value)

  handle_value(value)
end