lib/dojo/AdapterRegistry.js.uncompressed.js

   1 define("dojo/AdapterRegistry", ["./_base/kernel", "./_base/lang"], function(dojo, lang){
   2 // module:
   3 //              dojo/AdapterRegistry
   4
   5 var AdapterRegistry = dojo.AdapterRegistry = function(/*Boolean?*/ returnWrappers){
   6         // summary:
   7         //              A registry to make contextual calling/searching easier.
   8         // description:
   9         //              Objects of this class keep list of arrays in the form [name, check,
  10         //              wrap, directReturn] that are used to determine what the contextual
  11         //              result of a set of checked arguments is. All check/wrap functions
  12         //              in this registry should be of the same arity.
  13         // example:
  14         //      |       // create a new registry
  15         //      |       var reg = new dojo.AdapterRegistry();
  16         //      |       reg.register("handleString",
  17         //      |               dojo.isString,
  18         //      |               function(str){
  19         //      |                       // do something with the string here
  20         //      |               }
  21         //      |       );
  22         //      |       reg.register("handleArr",
  23         //      |               dojo.isArray,
  24         //      |               function(arr){
  25         //      |                       // do something with the array here
  26         //      |               }
  27         //      |       );
  28         //      |
  29         //      |       // now we can pass reg.match() *either* an array or a string and
  30         //      |       // the value we pass will get handled by the right function
  31         //      |       reg.match("someValue"); // will call the first function
  32         //      |       reg.match(["someValue"]); // will call the second
  33
  34         this.pairs = [];
  35         this.returnWrappers = returnWrappers || false; // Boolean
  36 };
  37
  38 lang.extend(AdapterRegistry, {
  39         register: function(/*String*/ name, /*Function*/ check, /*Function*/ wrap, /*Boolean?*/ directReturn, /*Boolean?*/ override){
  40                 // summary:
  41                 //              register a check function to determine if the wrap function or
  42                 //              object gets selected
  43                 // name:
  44                 //              a way to identify this matcher.
  45                 // check:
  46                 //              a function that arguments are passed to from the adapter's
  47                 //              match() function.  The check function should return true if the
  48                 //              given arguments are appropriate for the wrap function.
  49                 // directReturn:
  50                 //              If directReturn is true, the value passed in for wrap will be
  51                 //              returned instead of being called. Alternately, the
  52                 //              AdapterRegistry can be set globally to "return not call" using
  53                 //              the returnWrappers property. Either way, this behavior allows
  54                 //              the registry to act as a "search" function instead of a
  55                 //              function interception library.
  56                 // override:
  57                 //              If override is given and true, the check function will be given
  58                 //              highest priority. Otherwise, it will be the lowest priority
  59                 //              adapter.
  60                 this.pairs[((override) ? "unshift" : "push")]([name, check, wrap, directReturn]);
  61         },
  62
  63         match: function(/* ... */){
  64                 // summary:
  65                 //              Find an adapter for the given arguments. If no suitable adapter
  66                 //              is found, throws an exception. match() accepts any number of
  67                 //              arguments, all of which are passed to all matching functions
  68                 //              from the registered pairs.
  69                 for(var i = 0; i < this.pairs.length; i++){
  70                         var pair = this.pairs[i];
  71                         if(pair[1].apply(this, arguments)){
  72                                 if((pair[3])||(this.returnWrappers)){
  73                                         return pair[2];
  74                                 }else{
  75                                         return pair[2].apply(this, arguments);
  76                                 }
  77                         }
  78                 }
  79                 throw new Error("No match found");
  80         },
  81
  82         unregister: function(name){
  83                 // summary:
  84                 //              Remove a named adapter from the registry
  85                 // name: String
  86                 //              The name of the adapter.
  87                 // returns: Boolean
  88                 //              Returns true if operation is successful.
  89                 //              Returns false if operation fails.
  90
  91                 // FIXME: this is kind of a dumb way to handle this. On a large
  92                 // registry this will be slow-ish and we can use the name as a lookup
  93                 // should we choose to trade memory for speed.
  94                 for(var i = 0; i < this.pairs.length; i++){
  95                         var pair = this.pairs[i];
  96                         if(pair[0] == name){
  97                                 this.pairs.splice(i, 1);
  98                                 return true;
  99                         }
 100                 }
 101                 return false;
 102         }
 103 });
 104
 105 return AdapterRegistry;
 106 });