Adobe® Flex® 4 Language Reference
Hide Packages and Classes List |  Packages  |  Classes  |  Index  |  Appendixes
mx.charts.chartClasses 
InstanceCache 
Packagemx.charts.chartClasses
Classpublic class InstanceCache
InheritanceInstanceCache Inheritance Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

InstanceCache is a utility that governs the task of creating and managing a set of n object instances, where n changes frequently.



Public Properties
 PropertyDefined By
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
  count : int
The number of items currently required in the cache.
InstanceCache
  creationCallback : Function
A callback invoked when new instances are created.
InstanceCache
  discard : Boolean = false
Determines if unneeded instances are discarded.
InstanceCache
  factory : IFactory
A factory that generates the type of object to cache.
InstanceCache
  format : flash.text:TextFormat
A TextFormat to apply to any instances created.
InstanceCache
  hide : Boolean = true
Determines if unneeded instances should be hidden.
InstanceCache
  insertPosition : int
[write-only] The position of the instance in the parent's child list.
InstanceCache
  instances : Array
[read-only] The Array of cached instances.
InstanceCache
  properties : Object
A hashmap of properties to assign to new instances.
InstanceCache
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
Object
  remove : Boolean = false
Determines if unneeded instances should be removed from their parent.
InstanceCache
Public Methods
 MethodDefined By
  
InstanceCache(type:Object, parent:Object = null, insertPosition:int = -1)
Constructor.
InstanceCache
 Inherited
Indicates whether an object has a specified property defined.
Object
 Inherited
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
 Inherited
Indicates whether the specified property exists and is enumerable.
Object
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
Returns the string representation of the specified object.
Object
 Inherited
Returns the primitive value of the specified object.
Object
Property Detail

count

property
count:int

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The number of items currently required in the cache.



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

creationCallback

property 
public var creationCallback:Function

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

A callback invoked when new instances are created. This callback has the following signature:

      function creationCallback(newInstance:Object, cache:InstanceCache):void;
      

discard

property 
public var discard:Boolean = false

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Determines if unneeded instances are discarded. If set to true, extra elements are discarded when the cache count is reduced. Otherwise, extra elements are kept in a separate cache and reused when the count is increased.

factory

property 
factory:IFactory

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

A factory that generates the type of object to cache. Assigning to this discards all current instances and recreate new instances of the correct type.



Implementation
    public function get factory():IFactory
    public function set factory(value:IFactory):void

format

property 
format:flash.text:TextFormat

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

A TextFormat to apply to any instances created. If set, this format is applied as the current and default format for the contents of any instances created. This property is only relevant if the factory generates TextField instances.



Implementation
    public function get format():flash.text:TextFormat
    public function set format(value:flash.text:TextFormat):void

hide

property 
public var hide:Boolean = true

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Determines if unneeded instances should be hidden. If true, the visible property is set to false on each extra element when the cache count is reduced, and set to true when the count is increased.

This property is only relevant when the factory generates DisplayObjects. Setting this property to true for other factory types generates a run-time error.

insertPosition

property 
insertPosition:int  [write-only]

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The position of the instance in the parent's child list.



Implementation
    public function set insertPosition(value:int):void

instances

property 
instances:Array  [read-only]

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The Array of cached instances. There may be more instances in this Array than currently requested. You should rely on the count property of the instance cache rather than the length of this Array.



Implementation
    public function get instances():Array

properties

property 
properties:Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

A hashmap of properties to assign to new instances. Each key/value pair in this hashmap is assigned to each new instance created. The property hashmap is assigned to any existing instances when set.

The values in the hashmap are not cloned; object values are shared by all instances.



Implementation
    public function get properties():Object
    public function set properties(value:Object):void

remove

property 
public var remove:Boolean = false

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Determines if unneeded instances should be removed from their parent. If true, the removeChild() method is called on the parent for each extra element when the cache count is reduced.

This property is only relevant when the factory generates DisplayObjects. Setting this property to true for other factory types generates a run-time error.

Constructor Detail

InstanceCache

()Constructor
public function InstanceCache(type:Object, parent:Object = null, insertPosition:int = -1)

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Constructor.

Parameters
type:Object — The type of object to construct. This can be either a Class or an IFactory.
 
parent:Object (default = null) — An optional DisplayObject to add new instances to.
 
insertPosition:int (default = -1) — Where in the parent's child list to insert instances. Set to -1 to add the children to the end of the child list.