From: Steven Hahn <steverhahn@...>
Date: 2008-06-04T03:46:54+09:00
Subject: Re: [QUIZ] Price Ranges (#164)

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I hadn't planned on making another submission, but after tinkering with it =
a bit I realized a few things:

1. A simple GUI would be nice.  I used FXRuby.
2. The SAX Listener was barfing when the number of vendors was six or more.=
  Funny thing was that it only had a problem when the XML was formatted.  I=
f I removed the whitespace it did just fine.  In any case, I switched to us=
ing a StreamListener instead.
3. There was an inconsistency in the logic in my original in_range? method.

Anyway, here is the Ruby code followed by sample XML:
--------------------------------------------------------------
#!/usr/local/bin/ruby -w
require 'rexml/document'
require 'rexml/streamlistener'
require 'fox16'
include Fox

class VendorListener=20
  include REXML::StreamListener
  def initialize(low_price, high_price, vendor_search_window)
    begin
      @low_price =3D Float(low_price)
    rescue
      @low_price =3D 0
    end
   =20
    begin
      @high_price =3D Float(high_price)
    rescue
      #if someone can spend more than this then
      #she or he can afford a better program
      @high_price =3D 10**15
    end
   =20
    @vdr_srch_wdw =3D vendor_search_window
  end
 =20
  def tag_start(name, attrs)
    if name =3D=3D 'Vendor'
      @vendor_name =3D attrs['name']
    end
  end
 =20
  def tag_end(name)
    if name =3D=3D 'Vendor' and=20
      if in_range?
        @vdr_srch_wdw.add_vendor(@vendor_name)
      end
    elsif name =3D=3D 'LowPrice'
      @vendor_low_price =3D Float(@data)
    elsif name =3D=3D 'HighPrice'
      @vendor_high_price =3D Float(@data)
    end
  end

  def text(text)
    @data =3D text
  end

  def in_range?
    @low_price <=3D @high_price and
      (@low_price >=3D @vendor_low_price or @high_price >=3D @vendor_low_pr=
ice) and
      (@low_price <=3D @vendor_high_price or @high_price <=3D @vendor_high_=
price)
  end
end

class VendorSearchWindow < FXMainWindow
  def initialize(app)
    # Invoke base class initialize first
    super(app, "Ruby Quiz \#164: Vendor Search", nil, nil, DECOR_TITLE | DE=
COR_CLOSE)

    #Add text field frame at the top
    textfields =3D FXHorizontalFrame.new(self, LAYOUT_SIDE_TOP|LAYOUT_CENTE=
R_X)
    FXLabel.new(textfields, "Enter a range:", nil, JUSTIFY_LEFT)
    FXLabel.new(textfields, "low:", nil, JUSTIFY_RIGHT)
    @low_field =3D FXTextField.new(textfields, 10, nil, 0, JUSTIFY_RIGHT|FR=
AME_SUNKEN|FRAME_THICK|LAYOUT_SIDE_TOP)
    FXLabel.new(textfields, "high:", nil, JUSTIFY_RIGHT)
    @high_field =3D FXTextField.new(textfields, 10, nil, 0, JUSTIFY_RIGHT|F=
RAME_SUNKEN|FRAME_THICK|LAYOUT_SIDE_TOP)
   =20
    #add button frame at the bottom
    buttons =3D FXHorizontalFrame.new(self, LAYOUT_SIDE_BOTTOM|LAYOUT_CENTE=
R_X|PACK_UNIFORM_WIDTH)
    show_button =3D FXButton.new(buttons, "Show Vendors")
    show_button.connect(SEL_COMMAND, method(:on_show_vendors))
    exit_button =3D FXButton.new(buttons, "Exit")
    exit_button.connect(SEL_COMMAND, method(:on_exit))

    #Place the list in a sunken frame
    sunken_frame =3D FXHorizontalFrame.new(self,
            LAYOUT_FILL_X|LAYOUT_FILL_Y|FRAME_SUNKEN|FRAME_THICK, :padding =
=3D> 0)
    @vendor_list =3D FXList.new(sunken_frame, :opts =3D> LIST_SINGLESELECT|=
LAYOUT_FILL_X|LAYOUT_FILL_Y)
  end

  def on_exit(sender, sel, ptr)
    getApp().exit
  end
 =20
  def on_show_vendors(sender, sel, ptr)
    @vendor_list.clearItems(false)
    REXML::Document.parse_stream(File.new('vendors.xml' ),
      VendorListener.new(@low_field.text, @high_field.text, self))
  end
 =20
  def add_vendor(vndr_name)
    @vendor_list.appendItem(vndr_name)
  end
 =20
  def create
    super
    show(PLACEMENT_SCREEN)
  end
end

application =3D FXApp.new
VendorSearchWindow.new(application)
application.create
application.run
--------------------------------------------------------------
<?xml version=3D"1.0" encoding=3D"UTF-8"?>
<Vendors>
    <Vendor name=3D"Company A">
        <PriceRange>
            <LowPrice>1000</LowPrice>
            <HighPrice>3000</HighPrice>
        </PriceRange>
    </Vendor>
    <Vendor name=3D"Company B">
        <PriceRange>
            <LowPrice>6000</LowPrice>
            <HighPrice>10000</HighPrice>
        </PriceRange>
    </Vendor>
    <Vendor name=3D"Company C">
        <PriceRange>
            <LowPrice>500</LowPrice>
            <HighPrice>2500</HighPrice>
        </PriceRange>
    </Vendor>
</Vendors>



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