class Needle::ServicePoint
A “service point” is a definition of a service. Just as a class defines the behavior of an object, so does a service point describe a service. In particular, a service point also knows how to instantiate a service.
A ServicePoint should never be directly instantiated. Instead, define services via the interfaces provided by Container.
Attributes
A reference to the container that contains this service point.
The name of this service point, as it is known to the container that it was registered in.
The reference to the instantiation pipeline used by this service point.
Public Class Methods
Create a new service point that references the given container and has the given name. The associated callback will be used to instantiate the service on demand.
The :model
option is used to tell Needle which style of life-cycle management
should be used for the service. It defaults to :singleton
. The
model must be a symbol that refers to a service model that has been
registered in the root :service_models
service.
The :pipeline
option is mutually exclusive with
:model
. It must be an array of symbols (or strings) that
define the instantiation pipeline to use for this service. Each element
must correspond to an entry in the :pipeline_elements
service.
# File lib/needle/service-point.rb, line 54 def initialize( container, name, opts={}, &callback ) @name = name @container = container @callback = callback @pipeline = Needle::Pipeline::Collection.new self @chain = nil @chain_mutex = QueryableMutex.new @element_mutex = QueryableMutex.new if opts[:pipeline] elements = opts[:pipeline] else model = opts[:model] || :singleton elements = @container[:service_models][model] end elements.concat [ *opts[:include] ] if opts[:include] elements.each { |element| @pipeline.add element, opts } end
Public Instance Methods
Returns the fully-qualified name of the service point, with the point's name, its container's name, and all of its container's ancestors' names concatenated together with dot characters, i.e. “one.two.three”.
# File lib/needle/service-point.rb, line 78 def fullname container_name = @container.fullname if container_name "#{container_name}.#{@name}" else @name.to_s end end
Return the service instance represented by this service point. Depending on the style of lifecycle management chosen for this service point, this may or may not be a new instance for every invocation of this method.
The first argument is the container that should be used to resolve this service point. Assuming the container to be used is this service point's own container would mean that any nested service points couldn't override service points their parents' service points used.
Any extra arguments to this method will be passed through to the chain, which may cause an error if there is an element in the pipeline that does not accept additional arguments. Regardless, the first two parameters to the chain will always be the container and the service point.
# File lib/needle/service-point.rb, line 115 def instance( actual_container, *args ) unless @chain @chain_mutex.synchronize do @chain = @pipeline.chain_to( @callback ) unless @chain end end @chain.call( actual_container, self, *args ) end
Adds the given interceptor definition to this service point. The parameter should act like an instance of Interceptor.
# File lib/needle/service-point.rb, line 89 def interceptor( interceptor ) @element_mutex.synchronize do element = @pipeline.get( :interceptor ) unless element @pipeline.add( :interceptor ) element = @pipeline.get( :interceptor ) end element.interceptors << interceptor @pipeline.reset! @chain = nil end end