ContentCache

Package	spark.core
Class	public class ContentCache
Inheritance	ContentCache EventDispatcher Object
Implements	IContentLoader

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Provides a caching and queuing image content loader suitable for using a shared image cache for the BitmapImage and spark Image components.

Public Properties

	Property		Defined By
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		enableCaching : Boolean Enables caching behavior and functionality.	ContentCache
		enableQueueing : Boolean Enables queuing behavior and functionality.	ContentCache
		maxActiveRequests : int Maximum simultaneous active requests when queuing is enabled.	ContentCache
		maxCacheEntries : int Maximum size of MRU based cache.	ContentCache
		numCacheEntries : int [read-only] Count of active/in-use cache entries.	ContentCache

Protected Properties

	Property		Defined By
		activeRequests : LinkedList List of queued CacheEntryNode instances currently executing.	ContentCache
		cachedData : Dictionary Map of source to CacheEntryNode.	ContentCache
		cacheEntries : LinkedList Ordered (MRU) list of CacheEntryNode instances.	ContentCache
		priorityGroup : String = "_DEFAULT_" Identifier of the currently prioritized content grouping.	ContentCache
		requestQueue : LinkedList List of queued CacheEntryNode instances.	ContentCache

Public Methods

	Method		Defined By
		ContentCache() Constructor.	ContentCache
		addCacheEntry(source:Object, value:Object):void Adds new entry to cache (or replaces existing entry).	ContentCache
		addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.	EventDispatcher
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	EventDispatcher
		getCacheEntry(source:Object):Object Obtain an entry for the given key if one exists.	ContentCache
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	EventDispatcher
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		load(source:Object, contentLoaderGrouping:String = null):ContentRequest Initiates a content request for the resource identified by the key specified.	ContentCache
		prioritize(contentLoaderGrouping:String):void Promotes a content grouping to the head of the loading queue.	ContentCache
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		removeAllCacheEntries():void Resets our cache content to initial empty state.	ContentCache
		removeAllQueueEntries():void Resets the queue to initial empty state.	ContentCache
		removeCacheEntry(source:Object):void Remove specific entry from cache.	ContentCache
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	EventDispatcher
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns the string representation of the specified object.	Object
		valueOf():Object Returns the primitive value of the specified object.	Object
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	EventDispatcher

Events

Click for more information on events

	Summary	Defined By
activate	[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.	EventDispatcher
deactivate	[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.	EventDispatcher
invalidateLoader	Dispatched when a cache entry is invalidated, generally this occurs when the entry is determined to be untrusted while one or more outstanding load requests are active for a given cache entry.	ContentCache

Protected Constants

	Constant		Defined By
		UNTRUSTED : String = "untrusted" [static] Value used to mark cached URLs that are detected as being from an untrusted source (meaning they will no longer be shareable).	ContentCache

Property Detail

activeRequests

property

protected var activeRequests:LinkedList

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

List of queued CacheEntryNode instances currently executing.

cachedData

property

protected var cachedData:Dictionary

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Map of source to CacheEntryNode.

cacheEntries

property

protected var cacheEntries:LinkedList

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Ordered (MRU) list of CacheEntryNode instances.

enableCaching

property

enableCaching:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Enables caching behavior and functionality. Applies only to new load() requests.

The default value is true.

Implementation
public function get enableCaching():Boolean
public function set enableCaching(value:Boolean):void

enableQueueing

property

enableQueueing:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Enables queuing behavior and functionality. Applies only to new load() requests.

The default value is false.

Implementation
public function get enableQueueing():Boolean
public function set enableQueueing(value:Boolean):void

maxActiveRequests

property

maxActiveRequests:int

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Maximum simultaneous active requests when queuing is enabled.

The default value is 2.

Implementation
public function get maxActiveRequests():int
public function set maxActiveRequests(value:int):void

maxCacheEntries

property

maxCacheEntries:int

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Maximum size of MRU based cache. When numCacheEntries exceeds maxCacheEntries the least recently used are pruned to fit.

The default value is 100.

Implementation
public function get maxCacheEntries():int
public function set maxCacheEntries(value:int):void

numCacheEntries

property

numCacheEntries:int [read-only]

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Count of active/in-use cache entries.

Implementation
public function get numCacheEntries():int

priorityGroup

property

protected var priorityGroup:String = "_DEFAULT_"

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Identifier of the currently prioritized content grouping.

The default value is "_DEFAULT_".

requestQueue

property

protected var requestQueue:LinkedList

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

List of queued CacheEntryNode instances.

Constructor Detail

ContentCache

()

Constructor

public function ContentCache()

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Constructor.

Method Detail

addCacheEntry

()

method

public function addCacheEntry(source:Object, value:Object):void

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Adds new entry to cache (or replaces existing entry).

Parameters

	`source:Object` — Unique key to associate provided value with in cache.

	`value:Object` — Value to cache for given key.

getCacheEntry

()

method

public function getCacheEntry(source:Object):Object

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Obtain an entry for the given key if one exists.

Parameters

source:Object — Unique key used to represent the requested content resource.

Returns

Object — A value being stored by the cache for the provided key. Returns null if not found or in the likely case the value was stored as null.

load

()

method

public function load(source:Object, contentLoaderGrouping:String = null):ContentRequest

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 2.5

Initiates a content request for the resource identified by the key specified.

Parameters

	`source:Object` — Unique key used to represent the requested content resource. This parameter is typically an URL or URLRequest.

	`contentLoaderGrouping:String` (default = `null`) — - (Optional) grouping identifier for the loaded resource. ContentLoader instances supporting content groups generally allow for resources within the same named grouping to be addressed as a whole. For example the ContentCache's loader queue allows requests to be prioritized by contentLoaderGrouping.

Returns

ContentRequest — A ContentRequest instance representing the requested resource.

prioritize

()

method

public function prioritize(contentLoaderGrouping:String):void

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Promotes a content grouping to the head of the loading queue.

Parameters

contentLoaderGrouping:String — Name of content grouping to promote in the loading queue. All queued requests with matching contentLoaderGroup will be shifted to the head of the queue.

removeAllCacheEntries

()

method

public function removeAllCacheEntries():void

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Resets our cache content to initial empty state.

removeAllQueueEntries

()

method

public function removeAllQueueEntries():void

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Resets the queue to initial empty state. All requests, both active and queued, are cancelled. All cache entries associated with canceled requests are invalidated.

removeCacheEntry

()

method

public function removeCacheEntry(source:Object):void

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 1.5

Remove specific entry from cache.

Parameters

source:Object — Unique key for value to remove from cache.

Event Detail

invalidateLoader

Event

Event Object Type: spark.events.LoaderInvalidationEvent
property LoaderInvalidationEvent.type = spark.events.LoaderInvalidationEvent

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 10, AIR 2.0

Dispatched when a cache entry is invalidated, generally this occurs when the entry is determined to be untrusted while one or more outstanding load requests are active for a given cache entry. This mechanism allows any outstanding content requests to be reset due to the fact that the cache entry has been deemed 'unshareable'. Each content request notified then attempts instead re-requests the asset.

Constant Detail

UNTRUSTED

Constant

protected static const UNTRUSTED:String = "untrusted"

Language Version:

ActionScript 3.0

Product Version:

Flex 4.5

Runtime Versions:

Flash Player 9, AIR 1.1

Value used to mark cached URLs that are detected as being from an untrusted source (meaning they will no longer be shareable).

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ContentCache - AS3 Flex

Classes x

activeRequests

cachedData

cacheEntries

enableCaching

enableQueueing

maxActiveRequests

maxCacheEntries

numCacheEntries

priorityGroup

requestQueue

ContentCache

addCacheEntry

getCacheEntry

load

prioritize

removeAllCacheEntries

removeAllQueueEntries

removeCacheEntry

invalidateLoader

UNTRUSTED