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      1 
      2 <!--
      3 @license
      4 Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
      5 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
      6 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
      7 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
      8 Code distributed by Google as part of the polymer project is also
      9 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
     10 -->
     11 
     12 <link rel="import" href="../polymer/polymer.html">
     13 
     14 <script>
     15 
     16   /**
     17    * @param {!Function} selectCallback
     18    * @constructor
     19    */
     20   Polymer.IronSelection = function(selectCallback) {
     21     this.selection = [];
     22     this.selectCallback = selectCallback;
     23   };
     24 
     25   Polymer.IronSelection.prototype = {
     26 
     27     /**
     28      * Retrieves the selected item(s).
     29      *
     30      * @method get
     31      * @returns Returns the selected item(s). If the multi property is true,
     32      * `get` will return an array, otherwise it will return
     33      * the selected item or undefined if there is no selection.
     34      */
     35     get: function() {
     36       return this.multi ? this.selection.slice() : this.selection[0];
     37     },
     38 
     39     /**
     40      * Clears all the selection except the ones indicated.
     41      *
     42      * @method clear
     43      * @param {Array} excludes items to be excluded.
     44      */
     45     clear: function(excludes) {
     46       this.selection.slice().forEach(function(item) {
     47         if (!excludes || excludes.indexOf(item) < 0) {
     48           this.setItemSelected(item, false);
     49         }
     50       }, this);
     51     },
     52 
     53     /**
     54      * Indicates if a given item is selected.
     55      *
     56      * @method isSelected
     57      * @param {*} item The item whose selection state should be checked.
     58      * @returns Returns true if `item` is selected.
     59      */
     60     isSelected: function(item) {
     61       return this.selection.indexOf(item) >= 0;
     62     },
     63 
     64     /**
     65      * Sets the selection state for a given item to either selected or deselected.
     66      *
     67      * @method setItemSelected
     68      * @param {*} item The item to select.
     69      * @param {boolean} isSelected True for selected, false for deselected.
     70      */
     71     setItemSelected: function(item, isSelected) {
     72       if (item != null) {
     73         if (isSelected !== this.isSelected(item)) {
     74           // proceed to update selection only if requested state differs from current
     75           if (isSelected) {
     76             this.selection.push(item);
     77           } else {
     78             var i = this.selection.indexOf(item);
     79             if (i >= 0) {
     80               this.selection.splice(i, 1);
     81             }
     82           }
     83           if (this.selectCallback) {
     84             this.selectCallback(item, isSelected);
     85           }
     86         }
     87       }
     88     },
     89 
     90     /**
     91      * Sets the selection state for a given item. If the `multi` property
     92      * is true, then the selected state of `item` will be toggled; otherwise
     93      * the `item` will be selected.
     94      *
     95      * @method select
     96      * @param {*} item The item to select.
     97      */
     98     select: function(item) {
     99       if (this.multi) {
    100         this.toggle(item);
    101       } else if (this.get() !== item) {
    102         this.setItemSelected(this.get(), false);
    103         this.setItemSelected(item, true);
    104       }
    105     },
    106 
    107     /**
    108      * Toggles the selection state for `item`.
    109      *
    110      * @method toggle
    111      * @param {*} item The item to toggle.
    112      */
    113     toggle: function(item) {
    114       this.setItemSelected(item, !this.isSelected(item));
    115     }
    116 
    117   };
    118 
    119 </script>
    120