js设计模式-组合模式

组合模式是一种专为创建web上的动态用户界面而量身定制的模式。使用这种模式，可以用一条命令在多个对象上激发复杂的或递归的行为。这可以简化粘合性代码，使其更容易维护，而那些复杂行为则被委托给各个对象。

组合模式实例：图片库

 1 /**
 2  * 图片库
 3  */
 4  var Composite = new Interface("Composite",["add","remove","getChild"]);
 5  var GalleryItem = new Interface("GalleryItem",["hide","show"]);
 6  
 7 //DynamicGallery class
 8 
 9 var DynamicGallery = function(id){
10     this.children = [];
11     
12     this.element = document.createElement("div");
13     this.element.id = id;
14     this.element.className = "dynamic-gallery";
15 }
16 
17 DynamicGallery.prototype = {
18     add:function(child){
19         Interface.ensureImplements(child,Composite,GalleryItem);
20         this.children.push(child);
21         this.element.appendChild(child.getElement());
22     },
23     remove:function(child){
24         for(var i =0, node; node = this.getChild(i);i++){
25             if(node == child){
26                 this.children.splice(i,1);
27                 break;
28             }
29         }
30         this.element.removeChild(child.getElement());
31     },
32     getChild:function(i){
33         return this.children[i];
34     },
35     // Implemetn the GalleryItem interface
36     hide:function(){
37         for(var node, i =0; node = this.getChild(i);i++){
38             node.hide();
39         }
40         this.element.style.display = "none";
41     },
42     show:function(){
43         this.element.style.display = "block";
44         for(var node, i =0; node = this.getChild(i);i++){
45             node.show();
46         }
47     },
48     getElement:function(){
49         return this.element ;
50     }
51 }
52 
53 //GalleryImage class.
54 
55 var GalleryImage = function(src){
56     this.element  = document.createElement("img");
57     this.element.className = "gallery-image";
58     this.element.src =src;
59 }
60 
61 GalleryImage.prototype = {
62     add:function(){},
63     remove:function(){},
64     getChild:function(){},
65     hide:function(){
66         this.element.style.display = "none";
67     },
68     show:function(){
69         this.element.style.display = "";
70     },
71     
72     getElement:function(){
73         return this.element;
74     }
75 };
View Code

应用：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <div id="img"></div>
    </body>
</html>
<script type="text/javascript" src="Interface.js"></script>
<script type="text/javascript" src="ImageLibs.js"></script>
<script type="text/javascript">
    
    var topGallery = new DynamicGallery("top-gallery");
    topGallery.add(new GalleryImage("../img/dog/0.jpg"));
    topGallery.add(new GalleryImage("../img/dog/1.jpg"));
    topGallery.add(new GalleryImage("..//img/dog/2.jpg"));
    topGallery.add(new GalleryImage("../img/dog/3.jpg"));
    
    var vacationPhotos = new DynamicGallery("vacation-photos");
    for(var i = 0 ; i< 5;i++){
        vacationPhotos.add(new GalleryImage("../img/photo/" + i + ".jpg"));
    }
    
    topGallery.add(vacationPhotos);
    topGallery.show();
//    vacationPhotos.hide();
    console.log(topGallery);
    
    document.getElementById("img").appendChild(topGallery.element);
    
    topGallery.getChild(2).element.style.border = "2px solid red";

</script>

结果：

 

posted @ 2016-04-02 19:22  Tengri  阅读(236)  评论(0)  编辑  收藏  举报