| //////////////////////////////////////////////////////////////////////////////// |
| // |
| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to You under the Apache License, Version 2.0 |
| // (the "License"); you may not use this file except in compliance with |
| // the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| package mx.binding |
| { |
| |
| import flash.events.Event; |
| import flash.events.IEventDispatcher; |
| import flash.utils.getQualifiedClassName; |
| import mx.core.EventPriority; |
| import mx.core.mx_internal; |
| import mx.events.PropertyChangeEvent; |
| import mx.utils.DescribeTypeCache; |
| |
| use namespace mx_internal; |
| |
| [ExcludeClass] |
| |
| /** |
| * @private |
| */ |
| public class PropertyWatcher extends Watcher |
| { |
| include "../core/Version.as"; |
| |
| //-------------------------------------------------------------------------- |
| // |
| // Constructor |
| // |
| //-------------------------------------------------------------------------- |
| |
| /** |
| * Create a PropertyWatcher |
| * |
| * @param prop The name of the property to watch. |
| * @param event The event type that indicates the property has changed. |
| * @param listeners The binding objects that are listening to this Watcher. |
| * @param propertyGetter A helper function used to access non-public variables. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| public function PropertyWatcher(propertyName:String, |
| events:Object, |
| listeners:Array, |
| propertyGetter:Function = null) |
| { |
| super(listeners); |
| |
| _propertyName = propertyName; |
| this.events = events; |
| this.propertyGetter = propertyGetter; |
| useRTTI = !events; |
| } |
| |
| //-------------------------------------------------------------------------- |
| // |
| // Variables |
| // |
| //-------------------------------------------------------------------------- |
| |
| /** |
| * The parent object of this property. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| private var parentObj:Object; |
| |
| /** |
| * The events that indicate the property has changed |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| protected var events:Object; |
| |
| /** |
| * Storage for the propertyGetter property. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| protected var propertyGetter:Function; |
| |
| //-------------------------------------------------------------------------- |
| // |
| // Properties |
| // |
| //-------------------------------------------------------------------------- |
| |
| //---------------------------------- |
| // propertyName |
| //---------------------------------- |
| |
| /** |
| * Storage for the propertyName property. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| private var _propertyName:String; |
| |
| /** |
| * The name of the property this Watcher is watching. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| public function get propertyName():String |
| { |
| return _propertyName; |
| } |
| |
| //---------------------------------- |
| // useRTTI |
| //---------------------------------- |
| |
| /** |
| * If compiler can't determine bindability from static type, |
| * use RTTI on runtime values. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| private var useRTTI:Boolean; |
| |
| //-------------------------------------------------------------------------- |
| // |
| // Overridden methods: Watcher |
| // |
| //-------------------------------------------------------------------------- |
| |
| /** |
| * If the parent has changed we need to update ourselves |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| override public function updateParent(parent:Object):void |
| { |
| if (parentObj && parentObj is IEventDispatcher) |
| { |
| for (var eventType:String in events) |
| { |
| parentObj.removeEventListener(eventType, eventHandler); |
| } |
| } |
| |
| if (parent is Watcher) |
| parentObj = parent.value; |
| else |
| parentObj = parent; |
| |
| if (parentObj) |
| { |
| if (useRTTI) |
| { |
| // Use RTTI to ensure that parentObj is an IEventDispatcher, |
| // and that bindability metadata exists |
| // for parentObj[_propertyName]. |
| |
| events = {}; |
| |
| if (parentObj is IEventDispatcher) |
| { |
| var info:BindabilityInfo = |
| DescribeTypeCache.describeType(parentObj). |
| bindabilityInfo; |
| |
| events = info.getChangeEvents(_propertyName); |
| |
| if (objectIsEmpty(events)) |
| { |
| trace("warning: unable to bind to property '" + |
| _propertyName + "' on class '" + |
| getQualifiedClassName(parentObj) + "'"); |
| } |
| else |
| { |
| addParentEventListeners(); |
| } |
| } |
| else |
| { |
| trace("warning: unable to bind to property '" + |
| _propertyName + "' on class '" + |
| getQualifiedClassName(parentObj) + |
| "' (class is not an IEventDispatcher)"); |
| } |
| } |
| else |
| { |
| // useRTTI == false implies that the compiler |
| // has provided us with a list of change events. |
| // NOTE: this normally also implies that parentObj |
| // is guaranteed to implement IEventDispatcher. |
| // The guard below is necessitated by Proxy cases, |
| // which provide blanket bindability information |
| // on properties which are not strongly typed, |
| // and so could accept values that do not implement |
| // IEventDispatcher. |
| // In these cases, correct binding behavior depends on |
| // the Proxy implementation providing after-the-fact |
| // bindability by wrapping assigned values and attaching |
| // event listeners at that point. |
| // Here we can only fail silently. |
| |
| if (parentObj is IEventDispatcher) |
| addParentEventListeners(); |
| } |
| } |
| |
| // Now get our property. |
| wrapUpdate(updateProperty); |
| } |
| |
| /** |
| * @private |
| */ |
| override protected function shallowClone():Watcher |
| { |
| var clone:PropertyWatcher = new PropertyWatcher(_propertyName, |
| events, |
| listeners, |
| propertyGetter); |
| |
| return clone; |
| } |
| |
| //-------------------------------------------------------------------------- |
| // |
| // Methods |
| // |
| //-------------------------------------------------------------------------- |
| |
| /** |
| * @private |
| */ |
| private function addParentEventListeners():void |
| { |
| for (var eventType:String in events) |
| { |
| if (eventType != "__NoChangeEvent__") |
| { |
| parentObj.addEventListener( |
| eventType, eventHandler, false, EventPriority.BINDING, true); |
| } |
| } |
| } |
| |
| /** |
| * @private |
| */ |
| private function traceInfo():String |
| { |
| return "Watcher(" + getQualifiedClassName(parentObj) + "." + |
| _propertyName + "): events = [" + |
| eventNamesToString() + (useRTTI ? "] (RTTI)" : "]"); |
| } |
| |
| /** |
| * @private |
| */ |
| private function eventNamesToString():String |
| { |
| var s:String = " "; |
| |
| for (var ev:String in events) |
| { |
| s += ev + " "; |
| } |
| |
| return s; |
| } |
| |
| /** |
| * @private |
| */ |
| private function objectIsEmpty(o:Object):Boolean |
| { |
| for (var p:String in o) |
| { |
| return false; |
| } |
| return true; |
| } |
| |
| /** |
| * Gets the actual property then updates |
| * the Watcher's children appropriately. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| private function updateProperty():void |
| { |
| if (parentObj) |
| { |
| if (_propertyName == "this") |
| { |
| value = parentObj; |
| } |
| else |
| { |
| if (propertyGetter != null) |
| { |
| value = propertyGetter.apply(parentObj, [ _propertyName ]); |
| } |
| else |
| { |
| value = parentObj[_propertyName]; |
| } |
| } |
| } |
| else |
| { |
| value = null; |
| } |
| |
| updateChildren(); |
| } |
| |
| //-------------------------------------------------------------------------- |
| // |
| // Event handlers |
| // |
| //-------------------------------------------------------------------------- |
| |
| /** |
| * The generic event handler. |
| * The only event we'll hear indicates that the property has changed. |
| * |
| * @langversion 3.0 |
| * @playerversion Flash 9 |
| * @playerversion AIR 1.1 |
| * @productversion Flex 3 |
| */ |
| public function eventHandler(event:Event):void |
| { |
| if (event is PropertyChangeEvent) |
| { |
| var propName:Object = PropertyChangeEvent(event).property; |
| |
| if (propName != _propertyName) |
| return; |
| } |
| |
| wrapUpdate(updateProperty); |
| |
| notifyListeners(events[event.type]); |
| } |
| } |
| |
| } |
