Module: ActiveFedora::Delegating::ClassMethods

Defined in:
lib/active_fedora/delegating.rb

Instance Method Summary collapse

Instance Method Details

#delegate(*methods) ⇒ Object

Provides a delegate class method to expose methods in metadata streams as member of the base object. Pass the target datastream via the :to argument. If you want to return a multivalue result, (e.g. array instead of a string) set the :multiple argument to true.

The optional :at argument provides a terminology that the delegate will point to.

class Foo < ActiveFedora::Base
  has_metadata :name => "descMetadata", :type => MyDatastream

  delegate :field1, :to=>"descMetadata", multiple: false
  delegate :field2, :to=>"descMetadata", :at=>[:term1, :term2], multiple: true
end

foo = Foo.new
foo.field1 = "My Value"
foo.field1                 # => "My Value"
foo.field2                 # => [""]
foo.field3                 # => NoMethodError: undefined method `field3' for #<Foo:0x1af30c>

The optional <tt>:default</tt> forces this method to have the behavior defined by ActiveSupport
until this method has a chance to be removed

  delegate :method1, to: 'descMetadata', default: true



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# File 'lib/active_fedora/delegating.rb', line 31

def delegate(*methods)
  fields = methods.dup
  options = fields.pop
  unless options.is_a?(Hash) && to = options[:to]
    raise ArgumentError, "Target is required"
  end
  if ds_specs.has_key?(to.to_s) && !options[:default]
    Deprecation.warn(Delegating, "delegate is deprecated and will be removed in ActiveFedora 7.0. use has_attributes instead", caller(1))
    datastream = options.delete(:to)
    has_attributes fields.first, options.merge!({:datastream=>datastream})
  else
    super(*methods)
  end
end

#delegate_to(datastream, fields, args = {}) ⇒ Object

Allows you to delegate multiple terminologies to the same datastream, instead having to call the method each time for each term. The target datastream is the first argument, followed by an array of the terms that will point to that datastream. Terms must be a single value, ie. :field and not [:term1, :term2]. This is best accomplished by refining your OM terminology using :ref or :proxy methods to reduce nested terms down to one.

class Foo < ActiveFedora::Base
  has_metadata :name => "descMetadata", :type => MyDatastream

  delegate_to :descMetadata, [:field1, :field2]
end

foo = Foo.new
foo.field1 = "My Value"
foo.field1                 # => "My Value"
foo.field2                 # => [""]
foo.field3                 # => NoMethodError: undefined method `field3' for #<Foo:0x1af30c>



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# File 'lib/active_fedora/delegating.rb', line 65

def delegate_to(datastream,fields,args={})
  Deprecation.warn(Delegating, "delegate_to is deprecated and will be removed in ActiveFedora 7.0. use has_attributes instead", caller(1))
  has_attributes *fields, args.merge!({:datastream=>datastream})
end