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Contents
module Neo4j
module Embedded
# Wraps the Cypher query result.
# Loads the node and relationships wrapper if possible and use symbol as column keys.
# This is typically used in the native neo4j bindings since result does is not a Ruby enumerable with symbols as keys.
# @note The result is a once forward read only Enumerable, work if you need to read the result twice - use #to_a
#
class ResultWrapper
class ResultsAlreadyConsumedException < Exception
end
include Enumerable
# @return the original result from the Neo4j Cypher Engine, once forward read only !
attr_reader :source, :unwrapped
def initialize(source, query, unwrapped = nil)
@source = source
@struct = Struct.new(*source.columns.to_a.map!(&:to_sym)) unless source.columns.empty?
@unread = true
@query = query
@unwrapped = unwrapped
end
def to_s
@query
end
def unwrapped?
!!unwrapped
end
def inspect
"Enumerable query: '#{@query}'"
end
# @return [Array<Symbol>] the columns in the query result
def columns
@source.columns.map!(&:to_sym)
end
def each
fail ResultsAlreadyConsumedException unless @unread
if block_given?
@source.each do |row|
yield(row.each_with_object(@struct.new) do |(column, value), result|
result[column.to_sym] = unwrap(value)
end)
end
else
Enumerator.new(self)
end
end
private
def unwrap(value)
if !value.nil? && value.respond_to?(:to_a)
value.map { |v| unwrap(v) }
else
(!value.respond_to?(:wrapper) || unwrapped?) ? value : value.wrapper
end
end
end
end
end
Version data entries
4 entries across 4 versions & 1 rubygems