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Mongoid::Criteria

The Criteria class is the core object needed in Mongoid to retrieve objects from the database. It is a DSL that essentially sets up the selector and options arguments that get passed on to a Mongo::Collection in the Ruby driver. Each method on the Criteria returns self to they can be chained in order to create a readable criterion to be executed against the database.

@example Create and execute a criteria.

criteria = Criteria.new
criteria.only(:field).where(:field => "value").skip(20).limit(20)
criteria.execute

Attributes

documents[RW]
embedded[RW]
field_list[RW]
ids[RW]
klass[RW]
options[RW]
selector[RW]

Public Instance Methods

+(other) click to toggle source

Concatinate the criteria with another enumerable. If the other is a Criteria then it needs to get the collection from it.

@example Concat 2 criteria.

criteria + criteria

@param [ Criteria ] other The other criteria.

# File lib/mongoid/criteria.rb, line 75
def +(other)
  entries + comparable(other)
end
-(other) click to toggle source

Returns the difference between the criteria and another enumerable. If the other is a Criteria then it needs to get the collection from it.

@example Get the difference of 2 criteria.

criteria - criteria

@param [ Criteria ] other The other criteria.

# File lib/mongoid/criteria.rb, line 86
def -(other)
  entries - comparable(other)
end
==(other) click to toggle source

Returns true if the supplied Enumerable or Criteria is equal to the results of this Criteria or the criteria itself.

@note This will force a database load when called if an enumerable is passed.

@param [ Object ] other The other Enumerable or Criteria to compare to.

@return [ true, false ] If the objects are equal.

# File lib/mongoid/criteria.rb, line 98
def ==(other)
  case other
  when Criteria
    self.selector == other.selector && self.options == other.options
  when Enumerable
    return (execute.entries == other)
  else
    return false
  end
end
as_json(options = nil) click to toggle source

Needed to properly get a criteria back as json

@example Get the criteria as json.

Person.where(:title => "Sir").as_json

@param [ Hash ] options Options to pass through to the serializer.

@return [ String ] The JSON string.

# File lib/mongoid/criteria.rb, line 274
def as_json(options = nil)
  entries.as_json(options)
end
collection() click to toggle source

Get the collection associated with the criteria.

@example Get the collection.

criteria.collection

@return [ Collection ] The collection.

@since 2.2.0

# File lib/mongoid/criteria.rb, line 117
def collection
  klass.collection
end
context() click to toggle source

Return or create the context in which this criteria should be executed.

This will return an Enumerable context if the class is embedded, otherwise it will return a Mongo context for root classes.

@example Get the appropriate context.

criteria.context

@return [ Mongo, Enumerable ] The appropriate context.

# File lib/mongoid/criteria.rb, line 130
def context
  @context ||= Contexts.context_for(self, embedded)
end
each(&block) click to toggle source

Iterate over each Document in the results. This can take an optional block to pass to each argument in the results.

@example Iterate over the criteria results.

criteria.each { |doc| p doc }

@return [ Criteria ] The criteria itself.

# File lib/mongoid/criteria.rb, line 141
def each(&block)
  tap { context.iterate(&block) }
end
exists?() click to toggle source

Return true if the criteria has some Document or not.

@example Are there any documents for the criteria?

criteria.exists?

@return [ true, false ] If documents match.

# File lib/mongoid/criteria.rb, line 151
def exists?
  context.count > 0
end
extract_id() click to toggle source

Extract a single id from the provided criteria. Could be in an $and query or a straight _id query.

@example Extract the id.

criteria.extract_id

@return [ Object ] The id.

@since 2.3.0

# File lib/mongoid/criteria.rb, line 164
def extract_id
  selector[:_id]
end
freeze() click to toggle source

When freezing a criteria we need to initialize the context first otherwise the setting of the context on attempted iteration will raise a runtime error.

@example Freeze the criteria.

criteria.freeze

@return [ Criteria ] The frozen criteria.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 178
def freeze
  context and inclusions and super
end
fuse(criteria_conditions = {}) click to toggle source

Merges the supplied argument hash into a single criteria

@example Fuse the criteria and the object.

criteria.fuse(:where => { :field => "value"}, :limit => 20)

@param [ Hash ] criteria_conditions Criteria keys and values.

@return [ Criteria ] self.

# File lib/mongoid/criteria.rb, line 190
def fuse(criteria_conditions = {})
  criteria_conditions.inject(self) do |criteria, (key, value)|
    criteria.send(key, value)
  end
end
merge(other) click to toggle source

Merges another object with this Criteria and returns a new criteria. The other object may be a Criteria or a Hash. This is used to combine multiple scopes together, where a chained scope situation may be desired.

@example Merge the criteria with a conditions hash.

criteria.merge({ :conditions => { :title => "Sir" } })

@example Merge the criteria with another criteria.

criteri.merge(other_criteria)

@param [ Criteria, Hash ] other The other criterion to merge with.

@return [ Criteria ] A cloned self.

# File lib/mongoid/criteria.rb, line 223
def merge(other)
  clone.tap do |crit|
    if other.is_a?(Criteria)
      crit.selector.update(other.selector)
      crit.options.update(other.options)
      crit.documents = other.documents
    else
      duped = other.dup
      crit.selector.update(duped.delete(:conditions) || {})
      crit.options.update(duped)
    end
  end
end
raise_invalid() click to toggle source

Convenience method of raising an invalid options error.

@example Raise the error.

criteria.raise_invalid

@raise [ Errors::InvalidOptions ] The error.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 323
def raise_invalid
  raise Errors::InvalidFind.new
end
respond_to?(name, include_private = false) click to toggle source

Returns true if criteria responds to the given method.

@example Does the criteria respond to the method?

crtiteria.respond_to?(:each)

@param [ Symbol ] name The name of the class method on the Document. @param [ true, false ] include_private Whether to include privates.

@return [ true, false ] If the criteria responds to the method.

# File lib/mongoid/criteria.rb, line 246
def respond_to?(name, include_private = false)
  # don't include klass private methods because method_missing won't call them
  super || @klass.respond_to?(name) || entries.respond_to?(name, include_private)
end
scoped() click to toggle source

Returns the selector and options as a Hash that would be passed to a scope for use with named scopes.

@example Get the criteria as a scoped hash.

criteria.scoped

@return [ Hash ] The criteria as a scoped hash.

# File lib/mongoid/criteria.rb, line 258
def scoped
  scope_options = @options.dup
  sorting = scope_options.delete(:sort)
  scope_options[:order_by] = sorting if sorting
  { :where => @selector }.merge(scope_options)
end
search(*args) click to toggle source

Search for documents based on a variety of args.

@example Find by an id.

criteria.search(BSON::ObjectId.new)

@example Find by multiple ids.

criteria.search([ BSON::ObjectId.new, BSON::ObjectId.new ])

@example Conditionally find all matching documents.

criteria.search(:all, :conditions => { :title => "Sir" })

@example Conditionally find the first document.

criteria.search(:first, :conditions => { :title => "Sir" })

@example Conditionally find the last document.

criteria.search(:last, :conditions => { :title => "Sir" })

@param [ Symbol, BSON::ObjectId, Array<BSON::ObjectId> ] arg The

argument to search with.

@param [ Hash ] options The options to search with.

@return [ Array<Symbol, Criteria> ] The type and criteria.

@since 2.0.0

# File lib/mongoid/criteria.rb, line 302
def search(*args)
  raise_invalid if args[0].nil?
  type = args[0]
  params = args[1] || {}
  return [ :ids, for_ids(type) ] unless type.is_a?(Symbol)
  conditions = params.delete(:conditions) || {}
  if conditions.include?(:id)
    conditions[:_id] = conditions[:id]
    conditions.delete(:id)
  end
  return [ type, where(conditions).extras(params) ]
end

Protected Instance Methods

comparable(other) click to toggle source

Return the entries of the other criteria or the object. Used for comparing criteria or an enumerable.

@example Get the comparable version.

criteria.comparable(other)

@param [ Criteria ] other Another criteria.

@return [ Array ] The array to compare with.

# File lib/mongoid/criteria.rb, line 338
def comparable(other)
  other.is_a?(Criteria) ? other.entries : other
end
driver() click to toggle source

Get the raw driver collection from the criteria.

@example Get the raw driver collection.

criteria.driver

@return [ Mongo::Collection ] The driver collection.

@since 2.2.0

# File lib/mongoid/criteria.rb, line 350
def driver
  collection.driver
end
initialize_copy(other) click to toggle source

Clone or dup the current Criteria. This will return a new criteria with the selector, options, klass, embedded options, etc intact.

@example Clone a criteria.

criteria.clone

@example Dup a criteria.

criteria.dup

@param [ Criteria ] other The criteria getting cloned.

@return [ nil ] nil.

# File lib/mongoid/criteria.rb, line 366
def initialize_copy(other)
  @selector = other.selector.dup
  @options = other.options.dup
  @includes = other.inclusions.dup
  @context = nil
end
method_missing(name, *args, &block) click to toggle source

Used for chaining Criteria scopes together in the for of class methods on the Document the criteria is for.

# File lib/mongoid/criteria.rb, line 375
def method_missing(name, *args, &block)
  if @klass.respond_to?(name)
    @klass.send(:with_scope, self) do
      @klass.send(name, *args, &block)
    end
  else
    return entries.send(name, *args)
  end
end
update_selector(attributes, operator, combine = :+) click to toggle source

Update the selector setting the operator on the value for each key in the supplied attributes Hash.

@example Update the selector.

criteria.update_selector({ :field => "value" }, "$in")

@param [ Hash, Array ] attributes The values to convert and apply. @param [ String ] operator The MongoDB operator. @param [ Symbol ] combine The operator to use when combining sets.

# File lib/mongoid/criteria.rb, line 394
def update_selector(attributes, operator, combine = :+)
  clone.tap do |crit|
    converted = BSON::ObjectId.convert(klass, attributes || {})
    converted.each_pair do |key, value|
      existing = crit.selector[key]
      unless existing
        crit.selector[key] = { operator => value }
      else
        if existing.respond_to?(:merge)
          if existing.has_key?(operator)
            new_value = existing.values.first.send(combine, value)
            crit.selector[key] = { operator => new_value }
          else
            crit.selector[key][operator] = value
          end
        else
          crit.selector[key] = { operator => value }
        end
      end
    end
  end
end

Public Class Methods

new(klass, embedded = false) click to toggle source

Create the new Criteria object. This will initialize the selector and options hashes, as well as the type of criteria.

@example Instantiate a new criteria.

Criteria.new(Model, true)

@param [ Class ] klass The model the criteria is for. @param [ true, false ] embedded Is the criteria for embedded docs.

# File lib/mongoid/criteria.rb, line 204
def initialize(klass, embedded = false)
  @selector = Criterion::Selector.new(klass)
  @options, @klass, @documents, @embedded = {}, klass, [], embedded
end

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