Sha256: ce6b7878c2f87c952f439bea59e2567a14be153c1b715a6905f71ff7f5101c7c
Contents?: true
Size: 885 Bytes
Versions: 38
Compression:
Stored size: 885 Bytes
Contents
require 'arc-furnace/source'
# Filters limit rows to downstream nodes. They act just like Enumerable#filter:
# when the #filter method returns true, the row is passed downstream. when
# it returns false, the row is skipped.
module ArcFurnace
class Filter < Source
private_attr_reader :source
def initialize(source:)
@source = source
@value = nil
end
def value
if @value.nil? && !empty?
advance
end
@value
end
# Given a row from the source, tell if it should be passed down to the next
# node downstream from this node.
#
# This method must return a boolean
def filter(row)
raise "Unimplemented"
end
def empty?
@value.nil? && source.empty?
end
def advance
loop do
@value = source.row
break if value.nil? || filter(value)
end
end
end
end
Version data entries
38 entries across 38 versions & 1 rubygems