class Puppet::Pops::Adaptable::Adapter

Returns an existing adapter for the given object, or creates a new adapter if the object has not been adapted, or the adapter has been cleared.

@example Using a block to set values

NickNameAdapter.adapt(o) { |a| a.nick_name = "Buddy!" }
NickNameAdapter.adapt(o) { |a, o| a.nick_name = "Your the best #{o.class.name} I met."}

@overload adapt(o) @overload adapt(o, {|adapter| block}) @overload adapt(o, {|adapter, o| block}) @param o [Adaptable] object to add adapter to @yieldparam adapter [Adapter<self>] the created adapter @yieldparam o [Adaptable] optional, the given adaptable @param block [Proc] optional, evaluated in the context of the adapter (existing or new) @return [Adapter<self>] an adapter of the same class as the receiver of the call @raise [ArgumentError] if the given object o is not adaptable

# File lib/puppet/pops/adaptable.rb, line 94
def self.adapt(o, &block)
  attr_name = :"@#{instance_var_name(self.name)}"
  adapter = if o.instance_variable_defined?(attr_name) && value = o.instance_variable_get(attr_name)
    value
  else
    associate_adapter(create_adapter(o), o)
  end
  if block_given?
    case block.arity
      when 1
        block.call(adapter)
      else
        block.call(adapter, o)
    end
  end
  adapter
end

Creates a new adapter, associates it with the given object and returns the adapter.

@example Using a block to set values

NickNameAdapter.adapt_new(o) { |a| a.nick_name = "Buddy!" }
NickNameAdapter.adapt_new(o) { |a, o| a.nick_name = "Your the best #{o.class.name} I met."}

This is used when a fresh adapter is wanted instead of possible returning an existing adapter as in the case of {::adapt}. @overload ::adapt_new(o) @overload ::adapt_new(o, {|adapter| block}) @overload ::adapt_new(o, {|adapter, o| block}) @yieldparam adapter [Adapter<self>] the created adapter @yieldparam o [Adaptable] optional, the given adaptable @param o [Adaptable] object to add adapter to @param block [Proc] optional, evaluated in the context of the new adapter @return [Adapter<self>] an adapter of the same class as the receiver of the call @raise [ArgumentError] if the given object o is not adaptable

# File lib/puppet/pops/adaptable.rb, line 129
def self.adapt_new(o, &block)
  adapter = associate_adapter(create_adapter(o), o)
  if block_given?
    case block.arity
    when 1
      block.call(adapter)
    else
      block.call(adapter, o)
    end
  end
  adapter
end

Associates the given adapter with the given target object @param adapter [Adapter] the adapter to associate with the given object o @param o [Adaptable] the object to adapt @return [adapter] the given adapter

# File lib/puppet/pops/adaptable.rb, line 172
def self.associate_adapter(adapter, o)
  attr_name = :"@#{instance_var_name(adapter.class.name)}"
  o.instance_variable_set(attr_name, adapter)
  adapter
end

Clears the adapter set in the given object o. Returns any set adapter or nil. @param o [Adaptable] the object where the adapter should be cleared @return [Adapter] if an adapter was set @return [nil] if the adapter has not been set

# File lib/puppet/pops/adaptable.rb, line 147
def self.clear(o)
  attr_name = :"@#{instance_var_name(self.name)}"
  if o.instance_variable_defined?(attr_name)
    o.send(:remove_instance_variable, attr_name)
  else
    nil
  end
end

This base version creates an instance of the class (i.e. an instance of the concrete subclass of Adapter). A Specialization may want to create an adapter instance specialized for the given target object. @param o [Adaptable] The object to adapt. This implementation ignores this variable, but a

specialization may want to initialize itself differently depending on the object it is adapting.

@return [Adapter<self>] instance of the subclass of Adapter receiving the call

# File lib/puppet/pops/adaptable.rb, line 163
def self.create_adapter(o)
  new
end

Returns an existing adapter for the given object, or nil, if the object is not adapted.

@param o [Adaptable] object to get adapter from @return [Adapter<self>] an adapter of the same class as the receiver of get @return [nil] if the given object o has not been adapted by the receiving adapter @raise [ArgumentError] if the object is not adaptable

# File lib/puppet/pops/adaptable.rb, line 69
def self.get(o)
  attr_name = :"@#{instance_var_name(self.name)}"
  if o.instance_variable_defined?(attr_name)
    o.instance_variable_get(attr_name)
  else
    nil
  end
end

Returns a suitable instance variable name given a class name. The returned string is the fully qualified name of a class with ‘::’ replaced by ‘_’ since ‘::’ is not allowed in an instance variable name. @param name [String] the fully qualified name of a class @return [String] the name with all ‘::’ replaced by ‘_’ @api private @private

# File lib/puppet/pops/adaptable.rb, line 186
def self.instance_var_name(name)
  name.split("::").join('_')
end