git.pond.sub.org Git - eow/blob - static/dojo-release-1.1.1/dojo/data/util/sorter.js

   1 if(!dojo._hasResource["dojo.data.util.sorter"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
   2 dojo._hasResource["dojo.data.util.sorter"] = true;
   3 dojo.provide("dojo.data.util.sorter");
   4
   5 dojo.data.util.sorter.basicComparator = function(       /*anything*/ a,
   6                                                                                                         /*anything*/ b){
   7         //      summary:
   8         //              Basic comparision function that compares if an item is greater or less than another item
   9         //      description:
  10         //              returns 1 if a > b, -1 if a < b, 0 if equal.
  11         //              undefined values are treated as larger values so that they're pushed to the end of the list.
  12
  13         var ret = 0;
  14         if(a > b || typeof a === "undefined" || a === null){
  15                 ret = 1;
  16         }else if(a < b || typeof b === "undefined" || b === null){
  17                 ret = -1;
  18         }
  19         return ret; //int, {-1,0,1}
  20 };
  21
  22 dojo.data.util.sorter.createSortFunction = function(    /* attributes array */sortSpec,
  23                                                                                                                 /*dojo.data.core.Read*/ store){
  24         //      summary:
  25         //              Helper function to generate the sorting function based off the list of sort attributes.
  26         //      description:
  27         //              The sort function creation will look for a property on the store called 'comparatorMap'.  If it exists
  28         //              it will look in the mapping for comparisons function for the attributes.  If one is found, it will
  29         //              use it instead of the basic comparator, which is typically used for strings, ints, booleans, and dates.
  30         //              Returns the sorting function for this particular list of attributes and sorting directions.
  31         //
  32         //      sortSpec: array
  33         //              A JS object that array that defines out what attribute names to sort on and whether it should be descenting or asending.
  34         //              The objects should be formatted as follows:
  35         //              {
  36         //                      attribute: "attributeName-string" || attribute,
  37         //                      descending: true|false;   // Default is false.
  38         //              }
  39         //      store: object
  40         //              The datastore object to look up item values from.
  41         //
  42         var sortFunctions=[];
  43
  44         function createSortFunction(attr, dir){
  45                 return function(itemA, itemB){
  46                         var a = store.getValue(itemA, attr);
  47                         var b = store.getValue(itemB, attr);
  48                         //See if we have a override for an attribute comparison.
  49                         var comparator = null;
  50                         if(store.comparatorMap){
  51                                 if(typeof attr !== "string"){
  52                                          attr = store.getIdentity(attr);
  53                                 }
  54                                 comparator = store.comparatorMap[attr]||dojo.data.util.sorter.basicComparator;
  55                         }
  56                         comparator = comparator||dojo.data.util.sorter.basicComparator;
  57                         return dir * comparator(a,b); //int
  58                 };
  59         }
  60
  61         for(var i = 0; i < sortSpec.length; i++){
  62                 sortAttribute = sortSpec[i];
  63                 if(sortAttribute.attribute){
  64                         var direction = (sortAttribute.descending) ? -1 : 1;
  65                         sortFunctions.push(createSortFunction(sortAttribute.attribute, direction));
  66                 }
  67         }
  68
  69         return function(rowA, rowB){
  70                 var i=0;
  71                 while(i < sortFunctions.length){
  72                         var ret = sortFunctions[i++](rowA, rowB);
  73                         if(ret !== 0){
  74                                 return ret;//int
  75                         }
  76                 }
  77                 return 0; //int
  78         };  //  Function
  79 };
  80
  81 }