Class: ActsAsTable::Lense

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
app/models/acts_as_table/lense.rb

Overview

Note:

The name "Lense" was selected for 2 reasons: similarity of behavior of this class and the corresponding type(s) in the Haskell package, lens; and that "Attribute" is not allowed as a Ruby on Rails model class name (because the corresponding table name would be "attributes", which would conflict with ActiveRecord::AttributeMethods#attributes).

ActsAsTable attribute accessor (value provider).

Instance Attribute Summary collapse

Belongs to collapse

Has many collapse

Instance Attribute Details

#default_value ⇒ String?

Returns the default value for this ActsAsTable attribute accessor.

Returns:

  • (String, nil) 


14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
 
# File 'app/models/acts_as_table/lense.rb', line 14

class Lense < ::ActiveRecord::Base
  # @!parse
  #   include ActsAsTable::ValueProvider
  #   include ActsAsTable::ValueProvider::InstanceMethods
  #   include ActsAsTable::ValueProviderAssociationMethods

  self.table_name = ActsAsTable.lenses_table

  acts_as_table_value_provider

  # Returns the ActsAsTable column model for this ActsAsTable attribute accessor or `nil`.
  #
  # @return [ActsAsTable::ColumnModel, nil]
  belongs_to :column_model, **{
    class_name: 'ActsAsTable::ColumnModel',
    inverse_of: :lenses,
    required: false,
  }

  # Returns the ActsAsTable record model for this ActsAsTable attribute accessor.
  belongs_to :record_model, **{
    class_name: 'ActsAsTable::RecordModel',
    inverse_of: :lenses,
    required: true,
  }

  # Returns the ActsAsTable values that have been provided by this ActsAsTable attribute accessor.
  has_many :values, **{
    as: :value_provider,
    class_name: 'ActsAsTable::Value',
    dependent: :restrict_with_exception,
    foreign_key: 'value_provider_id',
    foreign_type: 'value_provider_type',
    inverse_of: :value_provider,
  }

  validates :default_value, **{
    presence: {
      unless: :column_model,
    },
  }

  validates :method_name, **{
    presence: true,
  }

  validate :record_model_class_must_respond_to_method_name, **{
    if: ::Proc.new { |lense| lense.method_name.present? },
  }

  protected

  # @param [ActiveRecord::Base, nil] base
  # @return [Object, nil]
  def _get_value(base = nil)
    if base.nil?
      nil
    else
      base.send(:"#{self.method_name}")
    end
  end

  # @param [ActiveRecord::Base, nil] base
  # @param [Object, nil] new_value
  # @return [Array<Object>]
  def _set_value(base = nil, new_value = nil)
    if base.nil?
      [
        nil,
        false,
      ]
    else
      # @return [Object, nil]
      orig_value = _get_value(base)

      # @return [Boolean]
      changed = !self.column_model.nil? && !(orig_value.nil? ? new_value.nil? : (new_value.nil? ? false : orig_value.to_s.eql?(new_value.to_s)))

      [
        base.send(:"#{self.method_name}=", new_value),
        changed,
      ]
    end
  end

  private

  # @param [Class] klass
  # @param [String] attribute_name
  # @return [Boolean]
  def _attr_accessor?(klass, attribute_name)
    [
      :"#{attribute_name}",
      :"#{attribute_name}=",
    ].all? { |sym|
      klass.instance_methods.include?(sym)
    }
  end

  # @param [Class] klass
  # @param [String] column_name
  # @return [Boolean]
  def _column?(klass, column_name)
    klass.column_names.include?(column_name.to_s)
  end

  # @return [void]
  def record_model_class_must_respond_to_method_name
    self.record_model.try { |record_model| record_model.class_name.constantize rescue nil }.try { |klass|
      unless _attr_accessor?(klass, self.method_name) || _column?(klass, self.method_name)
        self.errors.add('method_name', :required)
      end
    }

    return
  end
end

#method_name ⇒ String

Returns the method name for this ActsAsTable attribute accessor (an attr_reader or a Ruby on Rails model column name).

Returns:

  • (String) 


14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
 
# File 'app/models/acts_as_table/lense.rb', line 14

class Lense < ::ActiveRecord::Base
  # @!parse
  #   include ActsAsTable::ValueProvider
  #   include ActsAsTable::ValueProvider::InstanceMethods
  #   include ActsAsTable::ValueProviderAssociationMethods

  self.table_name = ActsAsTable.lenses_table

  acts_as_table_value_provider

  # Returns the ActsAsTable column model for this ActsAsTable attribute accessor or `nil`.
  #
  # @return [ActsAsTable::ColumnModel, nil]
  belongs_to :column_model, **{
    class_name: 'ActsAsTable::ColumnModel',
    inverse_of: :lenses,
    required: false,
  }

  # Returns the ActsAsTable record model for this ActsAsTable attribute accessor.
  belongs_to :record_model, **{
    class_name: 'ActsAsTable::RecordModel',
    inverse_of: :lenses,
    required: true,
  }

  # Returns the ActsAsTable values that have been provided by this ActsAsTable attribute accessor.
  has_many :values, **{
    as: :value_provider,
    class_name: 'ActsAsTable::Value',
    dependent: :restrict_with_exception,
    foreign_key: 'value_provider_id',
    foreign_type: 'value_provider_type',
    inverse_of: :value_provider,
  }

  validates :default_value, **{
    presence: {
      unless: :column_model,
    },
  }

  validates :method_name, **{
    presence: true,
  }

  validate :record_model_class_must_respond_to_method_name, **{
    if: ::Proc.new { |lense| lense.method_name.present? },
  }

  protected

  # @param [ActiveRecord::Base, nil] base
  # @return [Object, nil]
  def _get_value(base = nil)
    if base.nil?
      nil
    else
      base.send(:"#{self.method_name}")
    end
  end

  # @param [ActiveRecord::Base, nil] base
  # @param [Object, nil] new_value
  # @return [Array<Object>]
  def _set_value(base = nil, new_value = nil)
    if base.nil?
      [
        nil,
        false,
      ]
    else
      # @return [Object, nil]
      orig_value = _get_value(base)

      # @return [Boolean]
      changed = !self.column_model.nil? && !(orig_value.nil? ? new_value.nil? : (new_value.nil? ? false : orig_value.to_s.eql?(new_value.to_s)))

      [
        base.send(:"#{self.method_name}=", new_value),
        changed,
      ]
    end
  end

  private

  # @param [Class] klass
  # @param [String] attribute_name
  # @return [Boolean]
  def _attr_accessor?(klass, attribute_name)
    [
      :"#{attribute_name}",
      :"#{attribute_name}=",
    ].all? { |sym|
      klass.instance_methods.include?(sym)
    }
  end

  # @param [Class] klass
  # @param [String] column_name
  # @return [Boolean]
  def _column?(klass, column_name)
    klass.column_names.include?(column_name.to_s)
  end

  # @return [void]
  def record_model_class_must_respond_to_method_name
    self.record_model.try { |record_model| record_model.class_name.constantize rescue nil }.try { |klass|
      unless _attr_accessor?(klass, self.method_name) || _column?(klass, self.method_name)
        self.errors.add('method_name', :required)
      end
    }

    return
  end
end

Instance Method Details

#column_model ⇒ ActsAsTable::ColumnModel?

Returns the ActsAsTable column model for this ActsAsTable attribute accessor or nil.

Returns:



27
28
29
30
31
 
# File 'app/models/acts_as_table/lense.rb', line 27

belongs_to :column_model, **{
  class_name: 'ActsAsTable::ColumnModel',
  inverse_of: :lenses,
  required: false,
}

#record_model ⇒ ActsAsTable::RecordModel

Returns the ActsAsTable record model for this ActsAsTable attribute accessor.

Returns:

See Also:



34
35
36
37
38
 
# File 'app/models/acts_as_table/lense.rb', line 34

belongs_to :record_model, **{
  class_name: 'ActsAsTable::RecordModel',
  inverse_of: :lenses,
  required: true,
}

#values ⇒ ActiveRecord::Relation<ActsAsTable::Value>

Returns the ActsAsTable values that have been provided by this ActsAsTable attribute accessor.

Returns:

See Also:



41
42
43
44
45
46
47
48
 
# File 'app/models/acts_as_table/lense.rb', line 41

has_many :values, **{
  as: :value_provider,
  class_name: 'ActsAsTable::Value',
  dependent: :restrict_with_exception,
  foreign_key: 'value_provider_id',
  foreign_type: 'value_provider_type',
  inverse_of: :value_provider,
}