Class: FlatKit::Record

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/flat_kit/record.rb

Overview

Public: The base class that all record classes should inherit from.

Its goal is to be an efficient comparator of data that can be inflated from a source structure to a fully realized hash.

All records need to be able to be initialized from a data structure that it is handed to it by the Reader intance within the same Format.

Records are generally not going to be created outside of this library, they are tied to a specific format and provide a common interface that can be used for:

* comparison between records from different source / destinations formats
* conversion to a different format

Given that - the way to create a record is either from another Record instance:

Record.from_record(other)  # create a record from another record

or the way a Reader will do it

Record.new(...)            # generally only used by a Reader instance to
                           # yield new reocrds

When Implementing a new Format, the corresponding Record class for that Format must:

* implement `#[](key)` which will be used to lookup the values of the
  comparable fields.
* implement `#to_hash` which is used when conversions
* implement `.from_record` which is used in conversion
# the initialize method must call super(data:, compare_fields:) to
  initializa the root data structures

Direct Known Subclasses

Jsonl::Record, Xsv::Record

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data:, compare_fields:) ⇒ Record

Returns a new instance of Record.



44
45
46
47
 
# File 'lib/flat_kit/record.rb', line 44

def initialize(data:, compare_fields:)
  @data = data
  @compare_fields = compare_fields
end

Instance Attribute Details

#compare_fields ⇒ Object (readonly)

Returns the value of attribute compare_fields.



42
43
44
 
# File 'lib/flat_kit/record.rb', line 42

def compare_fields
  @compare_fields
end

#data ⇒ Object (readonly)

Returns the value of attribute data.



42
43
44
 
# File 'lib/flat_kit/record.rb', line 42

def data
  @data
end

Class Method Details

.from_record ⇒ Object

Raises:

  • (NotImplementedError) 


83
84
85
 
# File 'lib/flat_kit/record.rb', line 83

def self.from_record
  raise NotImplementedError, "#{self.class} must implement #{self.class}.from_record"
end

Instance Method Details

#<=>(other) ⇒ Object 



53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
 
# File 'lib/flat_kit/record.rb', line 53

def <=>(other)
  compare_result = nil

  compare_fields.each do |field|
    my_val         = self[field]
    other_val      = other[field]

    compare_result = if my_val.nil? && other_val.nil?
                       0
                     elsif my_val.nil?
                       -1
                     elsif other_val.nil?
                       1
                     else
                       my_val <=> (other_val)
                     end

    return compare_result unless compare_result.zero?
  end
  compare_result
end

#[](key) ⇒ Object

Raises:

  • (NotImplementedError) 


75
76
77
 
# File 'lib/flat_kit/record.rb', line 75

def [](key)
  raise NotImplementedError, "#{self.class} must implement #[](key)"
end

#format_name ⇒ Object 



49
50
51
 
# File 'lib/flat_kit/record.rb', line 49

def format_name
  self.class.format_name
end

#to_hash ⇒ Object

Raises:

  • (NotImplementedError) 


79
80
81
 
# File 'lib/flat_kit/record.rb', line 79

def to_hash
  raise NotImplementedError, "#{self.class} must implement #to_hash"
end