Using the Decorator Pattern for a Real Web Site - Setting Up the User Interface
(Page 4 of 6 )
The largest single class we’re going to use is the one to create the user interface. The line numbers appear in the Example 4-48 for the purpose of referencing lines in the code. A lot of the work done by this class, named Deal, is to set up the interface objects. These include the radio button, checkbox, and button components. Additionally, a good hunk of code is required for the text field output window and formatting for the output. So while the interface to the decorator pattern may look unwieldy, it’s not decorator pattern’s fault. In fact, only the getCar() (beginning on line 115) and getOptions() (beginning on line146) private functions are employed to pull out the information generated by the Decorator pattern.
To get a handle on what the class does, enter the code from Example 4-48 and save it asDeal.as.
Example 4-48. Deal.as
1package
2 {
3 import fl.controls.CheckBox;
4 import fl.controls.RadioButton;
5 import fl.controls.Button;
6 import flash.display.Sprite;
7 import flash.display.MovieClip;
8 import flash.events.MouseEvent;
9 import flash.text.TextField;
10 import flash.text.TextFormat;
11
12 public class Deal extends Sprite
13 {
14 internal var checks:Array=[];
15 internal var cars:Array=[];
16 internal var carDeal:Auto;
17 public var dealText:TextField=new TextField();
18
19 //Constructor Function
20 public function Deal ():void
21 {
22 getRadios ();
23 getChecks ();
24 doDealButton ();
25 showDeal ();
26 }
27 //Add button from Library
28 private function doDealButton ():void
29 {
30 var doDeal:Button=new Button();
31 this.addChild (doDeal);
32 doDeal.x=215;
33 doDeal.y=195;
34 doDeal.label="Make Deal";
35 doDeal.addEventListener (MouseEvent.CLICK,getPackage);
36 }
37 //**
38 //Get information from Decorator and display it
39 //**
40 private function getPackage (e:MouseEvent):void
41 {
42 getCar ();
43 getOptions ();
44 if (carDeal == null)
45 {
46 return;
47 }
48 else
49 {
50 var nowDrive:String=carDeal.getInformation()+"\nTotal=$"+carDeal.price();
51 }
52 dealText.text=formatMachine(nowDrive);
53 }
54 //Format Output
55 private function formatMachine (format:String):String
56 {
57 if (format.indexOf("~") != -1)
58 {
59 format=format.split("~").join("\n");
60 }
61 return format;
62 }
63 //Text Field & Format
64 private function showDeal ():void
65 {
66 dealText.width=150;
67 dealText.height=100;
68 dealText.wordWrap=true;
69 dealText.multiline=true;
70 dealText.x=165;
71 dealText.y=230;
72 dealText.border=true;
73 dealText.borderColor=0xcc0000;
74 var dealerFormat:TextFormat=new TextFormat();
75 dealerFormat.leftMargin=4;
76 dealerFormat.rightMargin=4;
77 dealText.defaultTextFormat=
dealerFormat;
78 this.addChild (dealText);
79 }
80 //Add Check boxes for Options (Concrete Decorators)
81 private function getChecks ():void
82 {
83 var gizmos:Array=new Array("MP3","Heated Seats","GPS", "Rear View Video");
84 var saloon:uint=gizmos.length;
85 var giz:uint;
86 for (giz=0; giz<saloon; giz++)
87 {
88 checks[giz]=new CheckBox();
89 this.addChild (checks[giz]);
90 checks[giz].width=150;
91 checks[giz].x=250;
92 checks[giz].y=80+(giz*30);
93 checks[giz].label=gizmos[giz];
94 }
95 }
96 //Add Radio buttons Auto (Concrete Components)
97 private function getRadios ():void
98 {
99 var car:Array=new Array("Escape","Mariner","Prius","Accord");
100 var saloon:uint=car.length;
101 var ride:uint;
102 for (ride=0; ride<saloon; ride++)
103 {
104 cars[ride]=new RadioButton();
105 cars[ride].groupName="deals";
106 this.addChild (cars[ride]);
107 cars[ride].x=150;
108 cars[ride].y=80+(ride*30);109 cars[ride].label=car[ride];110 }
111 }
112 //Select Auto and create Concrete Component
113 private function getCar ():void
114 {
115 var tracker:String;
116 var hybrid:uint;
117 for (hybrid=0; hybrid<cars.length; hybrid++)
118 {
119 if (cars[hybrid].selected)
120 {
121 tracker=cars[hybrid].label;
122 switch (tracker)
123 {
124 case "Escape" :
125 carDeal = new Escape();
126 break;
127
128 case "Mariner" :
129 carDeal = new Mariner();
130 break;
131
132 case "Prius" :
133 carDeal = new Prius();
134 break;
135
136 case "Accord" :
137 carDeal = new Accord();
138 break;
139 }
140 }
141 }
142 }
143 //Select options -- wrap Concrete Component in Decorator
144 private function getOptions ():void
145 {
146 var tracker:String;
147 var toy:uint;
148 for (toy=0; toy<checks.length; toy++)
149 {
150 if (checks[toy].selected)151 {
152 tracker=checks[toy].label;
153 switch (tracker)
154 {
155 case "MP3" :
156 carDeal = new MP3(carDeal);
157 break;
158
159 case "Heated Seats":160 carDeal = new HeatedSeats(carDeal);
161 break;
162
163 case "GPS":
164 carDeal = new GPS(carDeal);
165 break;
166
167 case "Rear View Video":
168 carDeal = new RearViewVideo(carDeal);
169 }
170 }
171 }
172 }
173 }
174 }
175
Next: Creating the document and setting the stage >>
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 This article is excerpted from chapter four of ActionScript 3.0 Design Patterns Object Oriented Programming Techniques, written by William B. Sanders and Chandima Cumaranatunge (O'Reilly, 2007 ISBN: 0596528469). Check it out today at your favorite bookstore. Buy this book now.
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