chrome/browser/resources/print_preview/data/ticket_items/ticket_item.js

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 cr.define('print_preview.ticket_items', function() {
   6   'use strict';
   7
   8   /**
   9    * An object that represents a user modifiable item in a print ticket. Each
  10    * ticket item has a value which can be set by the user. Ticket items can also
  11    * be unavailable for modifying if the print destination doesn't support it or
  12    * if other ticket item constraints are not met.
  13    * @param {?print_preview.AppState} appState Application state model to update
  14    *     when ticket items update.
  15    * @param {?print_preview.AppState.Field} field Field of the app state to
  16    *     update when ticket item is updated.
  17    * @param {?print_preview.DestinationStore} destinationStore Used listen for
  18    *     changes in the currently selected destination's capabilities. Since
  19    *     this is a common dependency of ticket items, it's handled in the base
  20    *     class.
  21    * @param {?print_preview.DocumentInfo=} opt_documentInfo Used to listen for
  22    *     changes in the document. Since this is a common dependency of ticket
  23    *     items, it's handled in the base class.
  24    * @constructor
  25    * @extends {cr.EventTarget}
  26    */
  27   function TicketItem(appState, field, destinationStore, opt_documentInfo) {
  28     cr.EventTarget.call(this);
  29
  30     /**
  31      * Application state model to update when ticket items update.
  32      * @type {print_preview.AppState}
  33      * @private
  34      */
  35     this.appState_ = appState || null;
  36
  37     /**
  38      * Field of the app state to update when ticket item is updated.
  39      * @type {?print_preview.AppState.Field}
  40      * @private
  41      */
  42     this.field_ = field || null;
  43
  44     /**
  45      * Used listen for changes in the currently selected destination's
  46      * capabilities.
  47      * @type {print_preview.DestinationStore}
  48      * @private
  49      */
  50     this.destinationStore_ = destinationStore || null;
  51
  52     /**
  53      * Used to listen for changes in the document.
  54      * @type {print_preview.DocumentInfo}
  55      * @private
  56      */
  57     this.documentInfo_ = opt_documentInfo || null;
  58
  59     /**
  60      * Backing store of the print ticket item.
  61      * @type {Object}
  62      * @private
  63      */
  64     this.value_ = null;
  65
  66     /**
  67      * Keeps track of event listeners for the ticket item.
  68      * @type {!EventTracker}
  69      * @private
  70      */
  71     this.tracker_ = new EventTracker();
  72
  73     this.addEventHandlers_();
  74   };
  75
  76   /**
  77    * Event types dispatched by this class.
  78    * @enum {string}
  79    */
  80   TicketItem.EventType = {
  81     CHANGE: 'print_preview.ticket_items.TicketItem.CHANGE'
  82   };
  83
  84   TicketItem.prototype = {
  85     __proto__: cr.EventTarget.prototype,
  86
  87     /**
  88      * Determines whether a given value is valid for the ticket item.
  89      * @param {?} value The value to check for validity.
  90      * @return {boolean} Whether the given value is valid for the ticket item.
  91      */
  92     wouldValueBeValid: function(value) {
  93       throw Error('Abstract method not overridden');
  94     },
  95
  96     /**
  97      * @return {boolean} Whether the print destination capability is available.
  98      */
  99     isCapabilityAvailable: function() {
 100       throw Error('Abstract method not overridden');
 101     },
 102
 103     /** @return {!Object} The value of the ticket item. */
 104     getValue: function() {
 105       if (this.isCapabilityAvailable()) {
 106         if (this.value_ == null) {
 107           return this.getDefaultValueInternal();
 108         } else {
 109           return this.value_;
 110         }
 111       } else {
 112         return this.getCapabilityNotAvailableValueInternal();
 113       }
 114     },
 115
 116     /** @return {boolean} Whether the ticket item was modified by the user. */
 117     isUserEdited: function() {
 118       return this.value_ != null;
 119     },
 120
 121     /** @return {boolean} Whether the ticket item's value is valid. */
 122     isValid: function() {
 123       if (!this.isUserEdited()) {
 124         return true;
 125       }
 126       return this.wouldValueBeValid(this.value_);
 127     },
 128
 129     /**
 130      * @param {?} value Value to compare to the value of this ticket item.
 131      * @return {boolean} Whether the given value is equal to the value of the
 132      *     ticket item.
 133      */
 134     isValueEqual: function(value) {
 135       return this.getValue() == value;
 136     },
 137
 138     /**
 139      * @param {?} value Value to set as the value of the ticket item.
 140      */
 141     updateValue: function(value) {
 142       // Use comparison with capabilities for event.
 143       var sendUpdateEvent = !this.isValueEqual(value);
 144       // Don't lose requested value if capability is not available.
 145       this.updateValueInternal(value);
 146       if (this.appState_) {
 147         this.appState_.persistField(this.field_, value);
 148       }
 149       if (sendUpdateEvent)
 150         cr.dispatchSimpleEvent(this, TicketItem.EventType.CHANGE);
 151     },
 152
 153     /**
 154      * @return {?} Default value of the ticket item if no value was set by
 155      *     the user.
 156      * @protected
 157      */
 158     getDefaultValueInternal: function() {
 159       throw Error('Abstract method not overridden');
 160     },
 161
 162     /**
 163      * @return {?} Default value of the ticket item if the capability is
 164      *     not available.
 165      * @protected
 166      */
 167     getCapabilityNotAvailableValueInternal: function() {
 168       throw Error('Abstract method not overridden');
 169     },
 170
 171     /**
 172      * @return {!EventTracker} Event tracker to keep track of events from
 173      *     dependencies.
 174      * @protected
 175      */
 176     getTrackerInternal: function() {
 177       return this.tracker_;
 178     },
 179
 180     /**
 181      * @return {print_preview.Destination} Selected destination from the
 182      *     destination store, or {@code null} if no destination is selected.
 183      * @protected
 184      */
 185     getSelectedDestInternal: function() {
 186       return this.destinationStore_ ?
 187           this.destinationStore_.selectedDestination : null;
 188     },
 189
 190     /**
 191      * @return {print_preview.DocumentInfo} Document data model.
 192      * @protected
 193      */
 194     getDocumentInfoInternal: function() {
 195       return this.documentInfo_;
 196     },
 197
 198     /**
 199      * Dispatches a CHANGE event.
 200      * @protected
 201      */
 202     dispatchChangeEventInternal: function() {
 203       cr.dispatchSimpleEvent(
 204           this, print_preview.ticket_items.TicketItem.EventType.CHANGE);
 205     },
 206
 207     /**
 208      * Updates the value of the ticket item without dispatching any events or
 209      * persisting the value.
 210      * @protected
 211      */
 212     updateValueInternal: function(value) {
 213       this.value_ = value;
 214     },
 215
 216     /**
 217      * Adds event handlers for this class.
 218      * @private
 219      */
 220     addEventHandlers_: function() {
 221       if (this.destinationStore_) {
 222         this.tracker_.add(
 223             this.destinationStore_,
 224             print_preview.DestinationStore.EventType.
 225                 SELECTED_DESTINATION_CAPABILITIES_READY,
 226             this.dispatchChangeEventInternal.bind(this));
 227       }
 228       if (this.documentInfo_) {
 229         this.tracker_.add(
 230             this.documentInfo_,
 231             print_preview.DocumentInfo.EventType.CHANGE,
 232             this.dispatchChangeEventInternal.bind(this));
 233       }
 234     },
 235   };
 236
 237   // Export
 238   return {
 239     TicketItem: TicketItem
 240   };
 241 });