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module Neo4j::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
def initialize(source, map_return_procs, query)
@source = source
@unread = true
@map_return_procs = map_return_procs
@query = query
end
def to_s
@query
end
# @return [Array<Symbol>] the columns in the query result
def columns
@source.columns.map { |x| x.to_sym }
end
# for the Enumerable contract
def each(&block)
raise ResultsAlreadyConsumedException unless @unread
if (block)
case @map_return_procs
when NilClass then
each_no_mapping &block
when Hash then
each_multi_column_mapping &block
else
each_single_column_mapping &block
end
else
Enumerator.new(self)
end
end
private
def each_no_mapping
@source.each do |row|
hash = {}
row.each do |key, value|
out[key.to_sym] = value
end
yield hash
end
end
def each_multi_column_mapping
@source.each do |row|
hash = {}
row.each do |key, value|
k = key.to_sym
proc = @map_return_procs[k]
hash[k] = proc ? proc.call(value) : value
end
yield hash
end
end
def each_single_column_mapping
@source.each do |row|
result = @map_return_procs.call(row.values.first)
yield result
end
end
end
end
Version data entries
6 entries across 6 versions & 1 rubygems