Class Needle::ServicePoint
In: lib/needle/service-point.rb
Parent: Object

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.

Methods

fullname   instance   interceptor   new  

Attributes

container  [R]  A reference to the container that contains this service point.
name  [R]  The name of this service point, as it is known to the container that it was registered in.
pipeline  [R]  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.

[Source]

    # File lib/needle/service-point.rb, line 54
54:     def initialize( container, name, opts={}, &callback )
55:       @name = name
56:       @container = container
57:       @callback = callback
58:       @pipeline = Needle::Pipeline::Collection.new self
59:       @chain = nil
60: 
61:       @chain_mutex = QueryableMutex.new
62:       @element_mutex = QueryableMutex.new
63: 
64:       if opts[:pipeline]
65:         elements = opts[:pipeline]
66:       else
67:         model = opts[:model] || :singleton
68:         elements = @container[:service_models][model]
69:       end
70: 
71:       elements.concat [ *opts[:include] ] if opts[:include]
72:       elements.each { |element| @pipeline.add element, opts }
73:     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".

[Source]

    # File lib/needle/service-point.rb, line 78
78:     def fullname
79:       container_name = @container.fullname
80:       if container_name
81:         "#{container_name}.#{@name}"
82:       else
83:         @name.to_s
84:       end
85:     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.

[Source]

     # File lib/needle/service-point.rb, line 115
115:     def instance( actual_container, *args )
116:       unless @chain
117:         @chain_mutex.synchronize do
118:           @chain = @pipeline.chain_to( @callback ) unless @chain
119:         end
120:       end
121: 
122:       @chain.call( actual_container, self, *args )
123:     end

Adds the given interceptor definition to this service point. The parameter should act like an instance of Interceptor.

[Source]

     # File lib/needle/service-point.rb, line 89
 89:     def interceptor( interceptor )
 90:       @element_mutex.synchronize do
 91:         element = @pipeline.get( :interceptor )
 92:         unless element
 93:           @pipeline.add( :interceptor )
 94:           element = @pipeline.get( :interceptor )
 95:         end
 96:         element.interceptors << interceptor
 97:         @pipeline.reset!
 98:         @chain = nil
 99:       end
100:     end

[Validate]