Class: Wee::Decoration

Inherits:
Presenter show all
Defined in:
lib/wee/decoration.rb

Overview

Abstract base class of all decorations. Forwards the methods #process_callbacks, #render_on and #state to the next decoration in the chain. Subclasses should provide special behaviour in these methods, otherwise the decoration does not make sense.

For example, a HeaderFooterDecoration class could draw a header and footer around the decorations or components below itself:

class HeaderFooterDecoration < Wee::Decoration
  alias render_on render_presenter_on
  def render(r)
    r.text "header"
    r.render_decoration(@next)
    r.text "footer"
  end
end

Direct Known Subclasses

AnswerDecoration, Delegate, WrapperDecoration

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Presenter

#render, #renderer_class

Instance Attribute Details

#next ⇒ Object

Points to the next decoration in the chain. A decoration is responsible for all decorations or components “below” it (everything that follows this decoration in the chain). In other words, it’s the owner of everything “below” itself.



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# File 'lib/wee/decoration.rb', line 31

def next
  @next
end

Instance Method Details

#global? ⇒ Boolean

Is this decoration a global or a local one? By default all decorations are local unless this method is overwritten.

A global decoration is added in front of the decoration chain, a local decoration is added in front of all other local decorations but after all global decorations.

Returns:

  • (Boolean) 


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# File 'lib/wee/decoration.rb', line 41

def global?() false end

#process_callbacks(callbacks) ⇒ Object

Forwards method call to the next decoration in the chain.



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# File 'lib/wee/decoration.rb', line 46

def process_callbacks(callbacks)
  @next.process_callbacks(callbacks)
end

#render_on(r) ⇒ Object

Forwards method call to the next decoration in the chain.



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# File 'lib/wee/decoration.rb', line 54

def render_on(r)
  @next.render_on(r)
end

#render_presenter_on ⇒ Object 



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# File 'lib/wee/decoration.rb', line 50

alias render_presenter_on render_on

#state(s) ⇒ Object

We have to save the @next attribute to be able to correctly backtrack calls, as method Wee::Component#call modifies it in the call to component.remove_decoration(answer). Removing the answer-decoration has the advantage to be able to call a component more than once!



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# File 'lib/wee/decoration.rb', line 65

def state(s)
  @next.state(s)
  s.add_ivar(self, :@next, @next)
end