The Collection class represents a list of resources persisted in a repository and identified by a query.
A Collection should act like an Array in every way, except that it will attempt to defer loading until the results from the repository are needed.
A Collection is typically returned by the Model#all method.
Returns the Query the Collection is scoped with
@return [Query]
the Query the Collection is scoped with
@api semipublic
Initializes a new Collection identified by the query
@param [Query] query
Scope the results of the Collection
@param [Enumerable] resources (optional)
List of resources to initialize the Collection with
@return [self]
@api private
# File lib/dm-core/collection.rb, line 1039 def initialize(query, resources = nil) raise "#{self.class}#new with a block is deprecated" if block_given? @query = query @identity_map = IdentityMap.new @removed = Set.new super() # TODO: change LazyArray to not use a load proc at all remove_instance_variable(:@load_with_proc) set(resources) if resources end
Append one Resource to the Collection and relate it
@param [Resource] resource
the resource to add to this collection
@return [self]
@api public
# File lib/dm-core/collection.rb, line 535 def <<(resource) super(resource_added(resource)) end
Simulates Array#slice and returns a new Collection whose query has a new offset or limit according to the arguments provided.
If you provide a range, the min is used as the offset and the max minues the offset is used as the limit.
@param [Integer, Array(Integer), Range] *args
the offset, offset and limit, or range indicating first and last position
@return [Resource, Collection, nil]
The entry which resides at that offset and limit, or a new Collection object with the set limits and offset
@return [nil]
The offset (or starting offset) is out of range
@raise [ArgumentError] "arguments may be 1 or 2 Integers,
or 1 Range object, was: #{args.inspect}"
@api public
# File lib/dm-core/collection.rb, line 389 def [](*args) offset, limit = extract_slice_arguments(*args) if args.size == 1 && args.first.kind_of?(Integer) return at(offset) end query = sliced_query(offset, limit) if loaded? || partially_loaded?(offset, limit) new_collection(query, super) else new_collection(query) end end
Splice a list of Resources at a given offset or range
When nil is provided instead of a Resource or a list of Resources this will remove all of the Resources at the specified position.
@param [Integer, Array(Integer), Range] *args
The offset, offset and limit, or range indicating first and last position. The last argument may be a Resource, a list of Resources or nil.
@return [Resource, Enumerable]
the Resource or list of Resources that was spliced into the Collection
@return [nil]
If nil was used to delete the entries
@api public
# File lib/dm-core/collection.rb, line 453 def []=(*args) orphans = Array(superclass_slice(*args[0..-2])) # relate new resources resources = resources_added(super) # mark resources as removed resources_removed(orphans - loaded_entries) resources end
Returns a new Collection optionally scoped by query
This returns a new Collection scoped relative to the current Collection.
cars_from_91 = Cars.all(:year_manufactured => 1991) toyotas_91 = cars_from_91.all(:manufacturer => 'Toyota') toyotas_91.all? { |car| car.year_manufactured == 1991 } #=> true toyotas_91.all? { |car| car.manufacturer == 'Toyota' } #=> true
If query is a Hash, results will be found by merging query with this Collection's query. If query is a Query, results will be found using query as an absolute query.
@param [Hash, Query] query
optional parameters to scope results with
@return [Collection]
Collection scoped by +query+
@api public
# File lib/dm-core/collection.rb, line 213 def all(query = Undefined) if query.equal?(Undefined) || (query.kind_of?(Hash) && query.empty?) dup else # TODO: if there is no order parameter, and the Collection is not loaded # check to see if the query can be satisfied by the head/tail new_collection(scoped_query(query)) end end
Lookup a Resource from the Collection by offset
@param [Integer] offset
offset of the Resource in the Collection
@return [Resource]
Resource which matches the supplied offset
@return [nil]
No Resource matches the supplied offset
@api public
# File lib/dm-core/collection.rb, line 346 def at(offset) if loaded? || partially_loaded?(offset) super elsif offset == 0 first elsif offset > 0 first(:offset => offset) elsif offset == -1 last else last(:offset => offset.abs - 1) end end
Checks if all the resources have no changes to save
@return [Boolean]
true if the resource may not be persisted
@api public
# File lib/dm-core/collection.rb, line 954 def clean? !dirty? end
Removes all Resources from the Collection
This should remove and orphan each Resource from the Collection
@return [self]
@api public
# File lib/dm-core/collection.rb, line 726 def clear if loaded? resources_removed(self) end super end
Invoke the block for each resource and replace it the return value
@yield [Resource] Each resource in the collection
@return [self]
@api public
# File lib/dm-core/collection.rb, line 521 def collect! super { |resource| resource_added(yield(resource_removed(resource))) } end
Appends the resources to self
@param [Enumerable] resources
List of Resources to append to the collection
@return [self]
@api public
# File lib/dm-core/collection.rb, line 547 def concat(resources) super(resources_added(resources)) end
Create a Resource in the Collection
@param [Hash(Symbol => Object)] attributes
attributes to set
@return [Resource]
the newly created Resource instance
@api public
# File lib/dm-core/collection.rb, line 792 def create(attributes = {}) _create(attributes) end
Create a Resource in the Collection, bypassing hooks
@param [Hash(Symbol => Object)] attributes
attributes to set
@return [Resource]
the newly created Resource instance
@api public
# File lib/dm-core/collection.rb, line 805 def create!(attributes = {}) _create(attributes, false) end
Remove Resource from the Collection
This should remove an included Resource from the Collection and orphan it from the Collection. If the Resource is not within the Collection, it should return nil.
@param [Resource] resource the Resource to remove from
the Collection
@return [Resource]
If +resource+ is within the Collection
@return [nil]
If +resource+ is not within the Collection
@api public
# File lib/dm-core/collection.rb, line 634 def delete(resource) if resource = super resource_removed(resource) end end
Remove Resource from the Collection by offset
This should remove the Resource from the Collection at a given offset and orphan it from the Collection. If the offset is out of range return nil.
@param [Integer] offset
the offset of the Resource to remove from the Collection
@return [Resource]
If +offset+ is within the Collection
@return [nil]
If +offset+ is not within the Collection
@api public
# File lib/dm-core/collection.rb, line 655 def delete_at(offset) if resource = super resource_removed(resource) end end
Deletes every Resource for which block evaluates to true.
@yield [Resource] Each resource in the Collection
@return [self]
@api public
# File lib/dm-core/collection.rb, line 668 def delete_if super { |resource| yield(resource) && resource_removed(resource) } end
Remove every Resource in the Collection from the repository
This performs a deletion of each Resource in the Collection from the repository and clears the Collection.
@return [Boolean]
true if the resources were successfully destroyed
@api public
# File lib/dm-core/collection.rb, line 894 def destroy if destroyed = all? { |resource| resource.destroy } clear end destroyed end
Remove all Resources from the repository, bypassing validation
This performs a deletion of each Resource in the Collection from the repository and clears the Collection while skipping validation.
@return [Boolean]
true if the resources were successfully destroyed
@api public
# File lib/dm-core/collection.rb, line 912 def destroy! repository = self.repository deleted = repository.delete(self) if loaded? unless deleted == size return false end each do |resource| resource.persistence_state = Resource::PersistenceState::Immutable.new(resource) end clear else mark_loaded end true end
Return the difference with another collection
@param [Collection] other
the other collection
@return [Collection]
the difference of the collection and other
@api public
# File lib/dm-core/collection.rb, line 123 def difference(other) set_operation(:-, other) end
Checks if any resources have unsaved changes
@return [Boolean]
true if the resources have unsaved changed
@api public
# File lib/dm-core/collection.rb, line 964 def dirty? loaded_entries.any? { |resource| resource.dirty? } || @removed.any? end
Iterate over each Resource
@yield [Resource] Each resource in the collection
@return [self]
@api public
# File lib/dm-core/collection.rb, line 503 def each super do |resource| begin original, resource.collection = resource.collection, self yield resource ensure resource.collection = original end end end
Return the first Resource or the first N Resources in the Collection with an optional query
When there are no arguments, return the first Resource in the Collection. When the first argument is an Integer, return a Collection containing the first N Resources. When the last (optional) argument is a Hash scope the results to the query.
@param [Integer] limit (optional)
limit the returned Collection to a specific number of entries
@param [Hash] query (optional)
scope the returned Resource or Collection to the supplied query
@return [Resource, Collection]
The first resource in the entries of this collection, or a new collection whose query has been merged
@api public
# File lib/dm-core/collection.rb, line 240 def first(*args) first_arg = args.first last_arg = args.last limit_specified = first_arg.kind_of?(Integer) with_query = (last_arg.kind_of?(Hash) && !last_arg.empty?) || last_arg.kind_of?(Query) limit = limit_specified ? first_arg : 1 query = with_query ? last_arg : {} query = self.query.slice(0, limit).update(query) # TODO: when a query provided, and there are enough elements in head to # satisfy the query.limit, filter the head with the query, and make # sure it matches the limit exactly. if so, use that result instead # of calling all() # - this can probably only be done if there is no :order parameter loaded = loaded? head = self.head collection = if !with_query && (loaded || lazy_possible?(head, limit)) new_collection(query, super(limit)) else all(query) end return collection if limit_specified resource = collection.to_a.first if with_query || loaded resource elsif resource head[0] = resource end end
Finds the first Resource by conditions, or creates a new Resource with the attributes if none found
@param [Hash] conditions
The conditions to be used to search
@param [Hash] attributes
The attributes to be used to create the resource with if none found
@return [Resource]
The instance found by +query+, or created with +attributes+ if none found
@api public
# File lib/dm-core/collection.rb, line 764 def first_or_create(conditions = {}, attributes = {}) first(conditions) || create(conditions.merge(attributes)) end
Finds the first Resource by conditions, or initializes a new Resource with the attributes if none found
@param [Hash] conditions
The conditions to be used to search
@param [Hash] attributes
The attributes to be used to initialize the resource with if none found
@return [Resource]
The instance found by +query+, or created with +attributes+ if none found
@api public
# File lib/dm-core/collection.rb, line 749 def first_or_new(conditions = {}, attributes = {}) first(conditions) || new(conditions.merge(attributes)) end
Lookup a Resource in the Collection by key
This looksup a Resource by key, typecasting the key to the proper object if necessary.
toyotas = Cars.all(:manufacturer => 'Toyota') toyo = Cars.first(:manufacturer => 'Toyota') toyotas.get(toyo.id) == toyo #=> true
@param [Enumerable] *key
keys which uniquely identify a resource in the Collection
@return [Resource]
Resource which matches the supplied key
@return [nil]
No Resource matches the supplied key
@api public
# File lib/dm-core/collection.rb, line 147 def get(*key) assert_valid_key_size(key) key = model_key.typecast(key) query = self.query @identity_map[key] || if !loaded? && (query.limit || query.offset > 0) # current query is exclusive, find resource within the set # TODO: use a subquery to retrieve the Collection and then match # it up against the key. This will require some changes to # how subqueries are generated, since the key may be a # composite key. In the case of DO adapters, it means subselects # like the form "(a, b) IN(SELECT a, b FROM ...)", which will # require making it so the Query condition key can be a # Property or an Array of Property objects # use the brute force approach until subquery lookups work lazy_load @identity_map[key] else # current query is all inclusive, lookup using normal approach first(model.key_conditions(repository, key).update(:order => nil)) end end
Lookup a Resource in the Collection by key, raising an exception if not found
This looksup a Resource by key, typecasting the key to the proper object if necessary.
@param [Enumerable] *key
keys which uniquely identify a resource in the Collection
@return [Resource]
Resource which matches the supplied key
@return [nil]
No Resource matches the supplied key
@raise [ObjectNotFoundError] Resource could not be found by key
@api public
# File lib/dm-core/collection.rb, line 189 def get!(*key) get(*key) || raise(ObjectNotFoundError, "Could not find #{model.name} with key #{key.inspect}") end
@api semipublic
# File lib/dm-core/collection.rb, line 980 def hash self.class.hash ^ query.hash end
Inserts the Resources before the Resource at the offset (which may be negative).
@param [Integer] offset
The offset to insert the Resources before
@param [Enumerable] *resources
List of Resources to insert
@return [self]
@api public
# File lib/dm-core/collection.rb, line 591 def insert(offset, *resources) super(offset, *resources_added(resources)) end
Gets a Human-readable representation of this collection, showing all elements contained in it
@return [String]
Human-readable representation of this collection, showing all elements
@api public
# File lib/dm-core/collection.rb, line 975 def inspect "[#{map { |resource| resource.inspect }.join(', ')}]" end
Return the intersection with another collection
@param [Collection] other
the other collection
@return [Collection]
the intersection of the collection and other
@api public
# File lib/dm-core/collection.rb, line 108 def intersection(other) set_operation(:&, other) end
Return the last Resource or the last N Resources in the Collection with an optional query
When there are no arguments, return the last Resource in the Collection. When the first argument is an Integer, return a Collection containing the last N Resources. When the last (optional) argument is a Hash scope the results to the query.
@param [Integer] limit (optional)
limit the returned Collection to a specific number of entries
@param [Hash] query (optional)
scope the returned Resource or Collection to the supplied query
@return [Resource, Collection]
The last resource in the entries of this collection, or a new collection whose query has been merged
@api public
# File lib/dm-core/collection.rb, line 295 def last(*args) first_arg = args.first last_arg = args.last limit_specified = first_arg.kind_of?(Integer) with_query = (last_arg.kind_of?(Hash) && !last_arg.empty?) || last_arg.kind_of?(Query) limit = limit_specified ? first_arg : 1 query = with_query ? last_arg : {} query = self.query.slice(0, limit).update(query).reverse! # tell the Query to prepend each result from the adapter query.update(:add_reversed => !query.add_reversed?) # TODO: when a query provided, and there are enough elements in tail to # satisfy the query.limit, filter the tail with the query, and make # sure it matches the limit exactly. if so, use that result instead # of calling all() loaded = loaded? tail = self.tail collection = if !with_query && (loaded || lazy_possible?(tail, limit)) new_collection(query, super(limit)) else all(query) end return collection if limit_specified resource = collection.to_a.last if with_query || loaded resource elsif resource tail[tail.empty? ? 0 : -1] = resource end end
Returns the Model
@return [Model]
the Model the Collection is associated with
@api semipublic
# File lib/dm-core/collection.rb, line 45 def model query.model end
Initializes a Resource and appends it to the Collection
@param [Hash] attributes
Attributes with which to initialize the new resource
@return [Resource]
a new Resource initialized with +attributes+
@api public
# File lib/dm-core/collection.rb, line 777 def new(attributes = {}) resource = repository.scope { model.new(attributes) } self << resource resource end
Removes and returns the last Resource in the Collection
@return [Resource]
the last Resource in the Collection
@api public
# File lib/dm-core/collection.rb, line 601 def pop(*) if removed = super resources_removed(removed) end end
Append one or more Resources to the Collection
This should append one or more Resources to the Collection and relate each to the Collection.
@param [Enumerable] *resources
List of Resources to append
@return [self]
@api public
# File lib/dm-core/collection.rb, line 562 def push(*resources) super(*resources_added(resources)) end
Deletes every Resource for which block evaluates to true
@yield [Resource] Each resource in the Collection
@return [Collection]
If resources were removed
@return [nil]
If no resources were removed
@api public
# File lib/dm-core/collection.rb, line 682 def reject! super { |resource| yield(resource) && resource_removed(resource) } end
Reloads the Collection from the repository
If query is provided, updates this Collection's query with its conditions
cars_from_91 = Cars.all(:year_manufactured => 1991) cars_from_91.first.year_manufactured = 2001 # note: not saved cars_from_91.reload cars_from_91.first.year #=> 1991
@param [Query, Hash] query (optional)
further restrict results with query
@return [self]
@api public
# File lib/dm-core/collection.rb, line 64 def reload(other_query = Undefined) query = self.query query = other_query.equal?(Undefined) ? query.dup : query.merge(other_query) # make sure the Identity Map contains all the existing resources identity_map = repository.identity_map(model) loaded_entries.each do |resource| identity_map[resource.key] = resource end # sort fields based on declared order, for more consistent reload queries properties = self.properties fields = properties & (query.fields | model_key | [ properties.discriminator ].compact) # replace the list of resources replace(all(query.update(:fields => fields, :reload => true))) end
Replace the Resources within the Collection
@param [Enumerable] other
List of other Resources to replace with
@return [self]
@api public
# File lib/dm-core/collection.rb, line 700 def replace(other) other = resources_added(other) resources_removed(entries - other) super(other) end
Returns the Repository
@return [Repository]
the Repository this Collection is associated with
@api semipublic
# File lib/dm-core/collection.rb, line 35 def repository query.repository end
Check to see if collection can respond to the method
@param [Symbol] method
method to check in the object
@param [Boolean] include_private
if set to true, collection will check private methods
@return [Boolean]
true if method can be responded to
@api public
# File lib/dm-core/collection.rb, line 944 def respond_to?(method, include_private = false) super || model.respond_to?(method) || relationships.named?(method) end
Return a copy of the Collection sorted in reverse
@return [Collection]
Collection equal to +self+ but ordered in reverse
@api public
# File lib/dm-core/collection.rb, line 473 def reverse dup.reverse! end
Return the Collection sorted in reverse
@return [self]
@api public
# File lib/dm-core/collection.rb, line 482 def reverse! query.reverse! # reverse without kicking if possible if loaded? @array.reverse! else # reverse and swap the head and tail @head, @tail = tail.reverse!, head.reverse! end self end
Save every Resource in the Collection
@return [Boolean]
true if the resources were successfully saved
@api public
# File lib/dm-core/collection.rb, line 871 def save _save end
Save every Resource in the Collection bypassing validation
@return [Boolean]
true if the resources were successfully saved
@api public
# File lib/dm-core/collection.rb, line 881 def save! _save(false) end
(Private) Set the Collection
@param [Array] resources
resources to add to the collection
@return [self]
@api private
# File lib/dm-core/collection.rb, line 714 def set(resources) superclass_replace(resources_added(resources)) self end
Removes and returns the first Resource in the Collection
@return [Resource]
the first Resource in the Collection
@api public
# File lib/dm-core/collection.rb, line 613 def shift(*) if removed = super resources_removed(removed) end end
Deletes and Returns the Resources given by an offset or a Range
@param [Integer, Array(Integer), Range] *args
the offset, offset and limit, or range indicating first and last position
@return [Resource, Collection]
The entry which resides at that offset and limit, or a new Collection object with the set limits and offset
@return [Resource, Collection, nil]
The offset is out of range
@api public
# File lib/dm-core/collection.rb, line 419 def slice!(*args) removed = super resources_removed(removed) unless removed.nil? # Workaround for Ruby <= 1.8.6 compact! if RUBY_VERSION <= '1.8.6' unless removed.kind_of?(Enumerable) return removed end offset, limit = extract_slice_arguments(*args) query = sliced_query(offset, limit) new_collection(query, removed) end
Access LazyArray#replace directly
@api private
Access LazyArray#slice directly
Collection#[]= uses this to bypass Collection#slice and access the resources directly so that it can orphan them properly.
@api private
Return the union with another collection
@param [Collection] other
the other collection
@return [Collection]
the union of the collection and other
@api public
# File lib/dm-core/collection.rb, line 92 def union(other) set_operation(:|, other) end
Prepend one or more Resources to the Collection
This should prepend one or more Resources to the Collection and relate each to the Collection.
@param [Enumerable] *resources
The Resources to prepend
@return [self]
@api public
# File lib/dm-core/collection.rb, line 577 def unshift(*resources) super(*resources_added(resources)) end
Update every Resource in the Collection
Person.all(:age.gte => 21).update(:allow_beer => true)
@param [Hash] attributes
attributes to update with
@return [Boolean]
true if the resources were successfully updated
@api public
# File lib/dm-core/collection.rb, line 820 def update(attributes) assert_update_clean_only(:update) dirty_attributes = model.new(attributes).dirty_attributes dirty_attributes.empty? || all? { |resource| resource.update(attributes) } end
Update every Resource in the Collection bypassing validation
Person.all(:age.gte => 21).update!(:allow_beer => true)
@param [Hash] attributes
attributes to update
@return [Boolean]
true if the resources were successfully updated
@api public
# File lib/dm-core/collection.rb, line 838 def update!(attributes) assert_update_clean_only(:update!) model = self.model dirty_attributes = model.new(attributes).dirty_attributes if dirty_attributes.empty? true elsif dirty_attributes.any? { |property, value| !property.valid?(value) } false else unless _update(dirty_attributes) return false end if loaded? each do |resource| dirty_attributes.each { |property, value| property.set!(resource, value) } repository.identity_map(model)[resource.key] = resource end end true end end
Loaded Resources in the collection
@return [Array<Resource>]
Resources in the collection
@api private
# File lib/dm-core/collection.rb, line 1002 def loaded_entries (loaded? ? self : head + tail).reject { |resource| resource.destroyed? } end
Returns the model key
@return [PropertySet]
the model key
@api private
# File lib/dm-core/collection.rb, line 992 def model_key model.key(repository_name) end
Returns the PropertySet representing the fields in the Collection scope
@return [PropertySet]
The set of properties this Collection's query will retrieve
@api private
# File lib/dm-core/collection.rb, line 1012 def properties model.properties(repository_name) end
Returns the Relationships for the Collection's Model
@return [Hash]
The model's relationships, mapping the name to the Associations::Relationship object
@api private
# File lib/dm-core/collection.rb, line 1023 def relationships model.relationships(repository_name) end
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