openlayers/lib/OpenLayers/Filter/Logical.js

   1 /* Copyright (c) 2006-2008 MetaCarta, Inc., published under the Clear BSD
   2  * license.  See http://svn.openlayers.org/trunk/openlayers/license.txt for the
   3   * full text of the license. */
   4
   5
   6 /**
   7  * @requires OpenLayers/Filter.js
   8  */
   9
  10 /**
  11  * Class: OpenLayers.Filter.Logical
  12  * This class represents ogc:And, ogc:Or and ogc:Not rules.
  13  *
  14  * Inherits from
  15  * - <OpenLayers.Filter>
  16  */
  17 OpenLayers.Filter.Logical = OpenLayers.Class(OpenLayers.Filter, {
  18
  19     /**
  20      * APIProperty: filters
  21      * {Array(<OpenLayers.Filter>)} Child filters for this filter.
  22      */
  23     filters: null,
  24
  25     /**
  26      * APIProperty: type
  27      * {String} type of logical operator. Available types are:
  28      * - OpenLayers.Filter.Logical.AND = "&&";
  29      * - OpenLayers.Filter.Logical.OR  = "||";
  30      * - OpenLayers.Filter.Logical.NOT = "!";
  31      */
  32     type: null,
  33
  34     /**
  35      * Constructor: OpenLayers.Filter.Logical
  36      * Creates a logical filter (And, Or, Not).
  37      *
  38      * Parameters:
  39      * options - {Object} An optional object with properties to set on the
  40      *     filter.
  41      *
  42      * Returns:
  43      * {<OpenLayers.Filter.Logical>}
  44      */
  45     initialize: function(options) {
  46         this.filters = [];
  47         OpenLayers.Filter.prototype.initialize.apply(this, [options]);
  48     },
  49
  50     /**
  51      * APIMethod: destroy
  52      * Remove reference to child filters.
  53      */
  54     destroy: function() {
  55         this.filters = null;
  56         OpenLayers.Filter.prototype.destroy.apply(this);
  57     },
  58
  59     /**
  60      * APIMethod: evaluate
  61      * Evaluates this filter in a specific context.  Should be implemented by
  62      *     subclasses.
  63      *
  64      * Parameters:
  65      * context - {Object} Context to use in evaluating the filter.
  66      *
  67      * Returns:
  68      * {Boolean} The filter applies.
  69      */
  70     evaluate: function(context) {
  71         switch(this.type) {
  72             case OpenLayers.Filter.Logical.AND:
  73                 for (var i=0, len=this.filters.length; i<len; i++) {
  74                     if (this.filters[i].evaluate(context) == false) {
  75                         return false;
  76                     }
  77                 }
  78                 return true;
  79
  80             case OpenLayers.Filter.Logical.OR:
  81                 for (var i=0, len=this.filters.length; i<len; i++) {
  82                     if (this.filters[i].evaluate(context) == true) {
  83                         return true;
  84                     }
  85                 }
  86                 return false;
  87
  88             case OpenLayers.Filter.Logical.NOT:
  89                 return (!this.filters[0].evaluate(context));
  90         }
  91     },
  92
  93     /**
  94      * APIMethod: clone
  95      * Clones this filter.
  96      *
  97      * Returns:
  98      * {<OpenLayers.Filter.Logical>} Clone of this filter.
  99      */
 100     clone: function() {
 101         var filters = [];
 102         for(var i=0, len=this.filters.length; i<len; ++i) {
 103             filters.push(this.filters[i].clone());
 104         }
 105         return new OpenLayers.Filter.Logical({
 106             type: this.type,
 107             filters: filters
 108         });
 109     },
 110
 111     CLASS_NAME: "OpenLayers.Filter.Logical"
 112 });
 113
 114
 115 OpenLayers.Filter.Logical.AND = "&&";
 116 OpenLayers.Filter.Logical.OR  = "||";
 117 OpenLayers.Filter.Logical.NOT = "!";