Class: Wee::Decoration

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

Overview

Abstract base class of all decorations. Forwards the methods #process_callbacks, #do_render and #backtrack_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
  def do_render(rendering_context)
    with_renderer_for(rendering_context) do
      render_header
      super(rendering_context)
      render_footer
    end
  end

  def render_header
    r.text "header
  end

  def render_footer
    ...
  end
end

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Presenter

#get_property, #lookup_property, #properties, #properties=, #render, #session, template, uses_property

Instance Attribute Details

#owner ⇒ 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/core/decoration.rb', line 34

def owner
  @owner
end

Instance Method Details

#backtrack_state(snapshot) ⇒ Object

Forwards method call to the next decoration in the chain.



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# File 'lib/wee/core/decoration.rb', line 59

def backtrack_state(snapshot)
  @owner.backtrack_state(snapshot)
  snapshot.add(self)
end

#do_render(rendering_context) ⇒ Object

Forwards method call to the next decoration in the chain.



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# File 'lib/wee/core/decoration.rb', line 53

def do_render(rendering_context)
  @owner.do_render(rendering_context)
end

#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/core/decoration.rb', line 43

def global?() false end

#process_callbacks(&block) ⇒ Object

Forwards method call to the next decoration in the chain.



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# File 'lib/wee/core/decoration.rb', line 47

def process_callbacks(&block)
  @owner.process_callbacks(&block)
end

#restore_snapshot(snap) ⇒ Object 



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# File 'lib/wee/core/decoration.rb', line 78

def restore_snapshot(snap)
  @owner = snap
end

#take_snapshot ⇒ Object

We have to save the @owner 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/core/decoration.rb', line 74

def take_snapshot
  @owner
end