Class: Mongoid::Contextual::None

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, `Queryable`, `Aggregable::None`, Enumerable
Inherits:	Object
Defined in:	lib/mongoid/contextual/none.rb

Overview

Context object used for performing bulk query and persistence operations on a null set. The method interface of this class is consistent with Mongoid::Contextual::Mongo.

Class Method Summary

.new(criteria) ⇒ None constructor

Create the new null context.

Instance Attribute Summary

#criteria readonly
#klass readonly

`Queryable` - Included

#blank?	Is the enumerable of matching documents empty?
#collection, #collection The collection to query against., #criteria, #criteria The criteria for the context.,
#empty?	Alias for Queryable#blank?.
#klass, #klass The klass for the criteria.

Instance Method Summary

#==(other) ⇒ true | false

Check if the context is equal to the other object.
#distinct(_field) ⇒ Array

Get the distinct field values in null context.
#each ⇒ Enumerator

Iterate over the null context.
#exists?(id_or_conditions = :none) ⇒ false

Do any documents exist for the context.
#fifth ⇒ nil

Always returns nil.
#fifth!

Always raises an error.
#find_first(limit = nil)

Alias for #first.
#first(limit = nil) ⇒ [] | nil (also: #find_first, #one)

Always returns nil.
#first!

Always raises an error.
#fourth ⇒ nil

Always returns nil.
#fourth!

Always raises an error.
#last(limit = nil) ⇒ [] | nil

Always returns nil.
#last!

Always raises an error.
#length ⇒ Integer (also: #size)

Always returns zero.
#one(limit = nil)

Alias for #first.
#pick(*_fields) ⇒ nil

Pick the field values in null context.
#pluck(*_fields) ⇒ Array

Pluck the field values in null context.
#second ⇒ nil

Always returns nil.
#second!

Always raises an error.
#second_to_last ⇒ nil

Always returns nil.
#second_to_last!

Always raises an error.
#size

Alias for #length.
#take(limit = nil) ⇒ [] | nil

Returns nil or empty array.
#take!

Always raises an error.
#tally(_field) ⇒ Hash

Tally the field values in null context.
#third ⇒ nil

Always returns nil.
#third!

Always raises an error.
#third_to_last ⇒ nil

Always returns nil.
#third_to_last!

Always raises an error.
#raise_document_not_found_error private

`Aggregable::None` - Included

#aggregates	Get all the aggregate values for the provided field in null context.
#avg	Always returns nil.
#max	Alias for Aggregable::None#min.
#min	Always returns nil.
#sum	Always returns zero.

Constructor Details

.new(criteria) ⇒ `None`

Create the new null context.

Examples:

Create the new context.

Null.new(criteria)

Parameters:

criteria (Criteria) —

The criteria.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 120


def initialize(criteria)
  @criteria, @klass = criteria, criteria.klass
end

Instance Attribute Details

#criteria (readonly)

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 17


attr_reader :criteria, :klass

#klass (readonly)

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 17


attr_reader :criteria, :klass

Instance Method Details

#==(other) ⇒ `true` | `false`

Check if the context is equal to the other object.

Examples:

Check equality.

context == []

Parameters:

other (Array) —

The other array.

Returns:

(true | false) —

If the objects are equal.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 27


def ==(other)
  other.is_a?(None)
end

#distinct(_field) ⇒ Array

Get the distinct field values in null context.

Examples:

Get the distinct values in null context.

context.distinct(:name)

Parameters:

_field (String | Symbol) —

The name of the field.

Returns:

(Array) —

An empty ::Array.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 39


def distinct(_field)
  []
end

#each ⇒ `Enumerator`

Iterate over the null context. There are no documents to iterate over in this case.

Examples:

Iterate over the null context.

context.each do |doc|
  puts doc.name
end

Returns:

(Enumerator) —

The enumerator.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 52


def each
  if block_given?
    [].each { |doc| yield(doc) }
    self
  else
    to_enum
  end
end

#exists?(id_or_conditions = :none) ⇒ `false`

Do any documents exist for the context.

Examples:

Do any documents exist in the null context.

context.exists?

Do any documents exist for given _id.

context.exists?(BSON::ObjectId(...))

Do any documents exist for given conditions.

context.exists?(name: "...")

Parameters:

id_or_conditions (Hash | Object | false) (defaults to: :none) —

an _id to search for, a hash of conditions, nil or false.

Returns:

(false) —

Always false.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 76


def exists?(id_or_conditions = :none); false; end

#fifth ⇒ `nil`

Always returns nil.

Examples:

Get the fifth document in null context.

context.fifth

Returns:

(nil) —

Always nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 256


def fifth
  nil
end

#fifth!

Always raises an error.

Examples:

Get the fifth document in null context.

context.fifth!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 266


def fifth!
  raise_document_not_found_error
end

#find_first(limit = nil)

Alias for #first.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 321


alias :find_first :first

#first(limit = nil) ⇒ [] | `nil` Also known as: #find_first, #one

Always returns nil.

Examples:

Get the first document in null context.

context.first

Parameters:

limit (Integer) (defaults to: nil) —

The number of documents to return.

Returns:

([] | nil) —

Empty array or nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 132


def first(limit = nil)
  [] unless limit.nil?
end

#first!

Always raises an error.

Examples:

Get the first document in null context.

context.first!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 142


def first!
  raise_document_not_found_error
end

#fourth ⇒ `nil`

Always returns nil.

Examples:

Get the fourth document in null context.

context.fourth

Returns:

(nil) —

Always nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 236


def fourth
  nil
end

#fourth!

Always raises an error.

Examples:

Get the fourth document in null context.

context.fourth!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 246


def fourth!
  raise_document_not_found_error
end

#last(limit = nil) ⇒ [] | `nil`

Always returns nil.

Examples:

Get the last document in null context.

context.last

Parameters:

limit (Integer) (defaults to: nil) —

The number of documents to return.

Returns:

([] | nil) —

Empty array or nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 154


def last(limit = nil)
  [] unless limit.nil?
end

#last!

Always raises an error.

Examples:

Get the last document in null context.

context.last!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 164


def last!
  raise_document_not_found_error
end

#length ⇒ Integer Also known as: #size

Always returns zero.

Examples:

Get the length of null context.

context.length

Returns:

(Integer) —

Always zero.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 316


def length
  entries.length
end

#one(limit = nil)

Alias for #first.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 322


alias :one :first

#pick(*_fields) ⇒ `nil`

Pick the field values in null context.

Examples:

Get the value for null context.

context.pick(:name)

Parameters:

*_fields ([ String | Symbol ]...) —

Field(s) to pick.

Returns:

(nil) —

Always return nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 98


def pick(*_fields)
  nil
end

#pluck(*_fields) ⇒ Array

Pluck the field values in null context.

Examples:

Get the values for null context.

context.pluck(:name)

Parameters:

*_fields ([ String | Symbol ]...) —

Field(s) to pluck.

Returns:

(Array) —

An empty ::Array.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 86


def pluck(*_fields)
  []
end

#raise_document_not_found_error (private)

Raises:

(Errors::DocumentNotFound)

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 326


def raise_document_not_found_error
  raise Errors::DocumentNotFound.new(klass, nil, nil)
end

#second ⇒ `nil`

Always returns nil.

Examples:

Get the second document in null context.

context.second

Returns:

(nil) —

Always nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 196


def second
  nil
end

#second!

Always raises an error.

Examples:

Get the second document in null context.

context.second!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 206


def second!
  raise_document_not_found_error
end

#second_to_last ⇒ `nil`

Always returns nil.

Examples:

Get the second to last document in null context.

context.second_to_last

Returns:

(nil) —

Always nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 276


def second_to_last
  nil
end

#second_to_last!

Always raises an error.

Examples:

Get the second to last document in null context.

context.second_to_last!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 286


def second_to_last!
  raise_document_not_found_error
end

#size

Alias for #length.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 319


alias :size :length

#take(limit = nil) ⇒ [] | `nil`

Returns nil or empty array.

Examples:

Take a document in null context.

context.take

Parameters:

limit (Integer | nil) (defaults to: nil) —

The number of documents to take or nil.

Returns:

([] | nil) —

Empty array or nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 176


def take(limit = nil)
  limit ? [] : nil
end

#take!

Always raises an error.

Examples:

Take a document in null context.

context.take!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 186


def take!
  raise_document_not_found_error
end

#tally(_field) ⇒ Hash

Tally the field values in null context.

Examples:

Get the values for null context.

context.tally(:name)

Parameters:

_field (String | Symbol) —

Field to tally.

Returns:

(Hash) —

An empty ::Hash.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 110


def tally(_field)
  {}
end

#third ⇒ `nil`

Always returns nil.

Examples:

Get the third document in null context.

context.third

Returns:

(nil) —

Always nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 216


def third
  nil
end

#third!

Always raises an error.

Examples:

Get the third document in null context.

context.third!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 226


def third!
  raise_document_not_found_error
end

#third_to_last ⇒ `nil`

Always returns nil.

Examples:

Get the third to last document in null context.

context.third_to_last

Returns:

(nil) —

Always nil.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 296


def third_to_last
  nil
end

#third_to_last!

Always raises an error.

Examples:

Get the third to last document in null context.

context.third_to_last!

Raises:

(Mongoid::Errors::DocumentNotFound) —

always raises.

[ GitHub ]

# File 'lib/mongoid/contextual/none.rb', line 306


def third_to_last!
  raise_document_not_found_error
end

Class: Mongoid::Contextual::None

Overview

Class Method Summary

Instance Attribute Summary

Queryable - Included

Instance Method Summary

Aggregable::None - Included

Constructor Details

.new(criteria) ⇒ None

Instance Attribute Details

#criteria (readonly)

#klass (readonly)

Instance Method Details

#==(other) ⇒ true | false

#distinct(_field) ⇒ Array

#each ⇒ Enumerator

#exists?(id_or_conditions = :none) ⇒ false

#fifth ⇒ nil

#fifth!

#find_first(limit = nil)

#first(limit = nil) ⇒ [] | nil Also known as: #find_first, #one

#first!

#fourth ⇒ nil

#fourth!

#last(limit = nil) ⇒ [] | nil

#last!

#length ⇒ Integer Also known as: #size

#one(limit = nil)

#pick(*_fields) ⇒ nil

#pluck(*_fields) ⇒ Array

#raise_document_not_found_error (private)

#second ⇒ nil

#second!

#second_to_last ⇒ nil

#second_to_last!

#size

#take(limit = nil) ⇒ [] | nil

#take!

#tally(_field) ⇒ Hash

#third ⇒ nil

#third!

#third_to_last ⇒ nil

#third_to_last!

`Queryable` - Included

`Aggregable::None` - Included

.new(criteria) ⇒ `None`

#==(other) ⇒ `true` | `false`

#each ⇒ `Enumerator`

#exists?(id_or_conditions = :none) ⇒ `false`

#fifth ⇒ `nil`

#first(limit = nil) ⇒ [] | `nil` Also known as: #find_first, #one

#fourth ⇒ `nil`

#last(limit = nil) ⇒ [] | `nil`

#pick(*_fields) ⇒ `nil`

#second ⇒ `nil`

#second_to_last ⇒ `nil`

#take(limit = nil) ⇒ [] | `nil`

#third ⇒ `nil`

#third_to_last ⇒ `nil`