Packagecom.yworks.graph.model
Classpublic class LookupDecorator
InheritanceLookupDecorator Inheritance Object


Public Properties
 PropertyDefined By
  decorateNull : Boolean
Whether to decorate null values.
LookupDecorator
  decorator : ILookupDecorator
The decorator to use.
LookupDecorator
  nullIsFallback : Boolean
Whether to continue in the chain if a chain link yiels null.
LookupDecorator
Public Methods
 MethodDefined By
  
LookupDecorator(forItem:Class, implementation:Class, decorator:ILookupDecorator, decorateNull:Boolean = false, nullIsFallback:Boolean = false)
Utility class which enables convenient decoration of look-up chains on top of a given ILookupDecorator.
LookupDecorator
  
hideImplementation(predicate:Function = null):IContextLookupChainLink
Creates a chain link which always returns null when an implementation of the asked type is requested.
LookupDecorator
  
setFactory(factory:Function, predicate:Function = null):IContextLookupChainLink
Creates a chain link and decorates the decorator with it.
LookupDecorator
  
setImplementationWrapper(wrapperFactory:Function, predicate:Function = null):IContextLookupChainLink
Creates a chain link which returns an implementation of the asked type which wraps the default (actually the recently added chain link for the same item and implementation type).
LookupDecorator
  
setInstance(instance:Object, predicate:Function = null):IContextLookupChainLink
Creates a chain link which returns the given instance when asked for the item and implementation type this LookupDecorator is created for.
LookupDecorator
Property Detail
decorateNullproperty
decorateNull:Boolean

Whether to decorate null values.

If set to true wrappers created by the wrapper factory set by setImplementationWrapper() will be created even if they wrap a null value. If set to false, a null value won't be wrapped; instead null will be returned.

Setting a different value will not affect existing chain links.


Implementation
    public function get decorateNull():Boolean
    public function set decorateNull(value:Boolean):void
decoratorproperty 
decorator:ILookupDecorator

The decorator to use.

Setting a different value will not affect existing chain links.


Implementation
    public function get decorator():ILookupDecorator
    public function set decorator(value:ILookupDecorator):void
nullIsFallbackproperty 
nullIsFallback:Boolean

Whether to continue in the chain if a chain link yiels null.

If a factory method (set by setFactory()) yields null the search in the lookup chain will be continued if this value is set to true. This is equivalent to use the default implementaion as fallback.

Setting a different value will not affect existing chain links.


Implementation
    public function get nullIsFallback():Boolean
    public function set nullIsFallback(value:Boolean):void
Constructor Detail
LookupDecorator()Constructor
public function LookupDecorator(forItem:Class, implementation:Class, decorator:ILookupDecorator, decorateNull:Boolean = false, nullIsFallback:Boolean = false)

Utility class which enables convenient decoration of look-up chains on top of a given ILookupDecorator.

Parameters
forItem:Class — The item class to decorate.
 
implementation:Class — The type of implementation which is looked up for.
 
decorator:ILookupDecorator — The decorator to use.
 
decorateNull:Boolean (default = false) — Whether calls that yield null will be decorated by wrapper factories set by setImplementationWrapper().
 
nullIsFallback:Boolean (default = false) — If a factory method (set by setFactory()) yields null the search in the lookup chain will be continued if this value is set to true, otherwise null will be returned.
Method Detail
hideImplementation()method
public function hideImplementation(predicate:Function = null):IContextLookupChainLink

Creates a chain link which always returns null when an implementation of the asked type is requested. This will efficiently disable the default.

A predicate function function( item:Object ):Boolean will be queried whether to return null for the given item or to continue searching in the chain. If no predicate is given the created link will always return null if the correct type is asked for the given item.

Parameters

predicate:Function (default = null) — A predicate method which will return true if null should be returned for the given item. If no predicate is provided null will always be returned.

Returns
IContextLookupChainLink — The chain link which is created and added to the lookup chain.
setFactory()method 
public function setFactory(factory:Function, predicate:Function = null):IContextLookupChainLink

Creates a chain link and decorates the decorator with it.

The chain link delegates to the given factory method function( item:Object ):Object which creates an implementation of the asked type for the given item.

A predicate function function( item:Object ):Boolean will be queried whether to invoke the factory for the given item or to continue searching in the chain (using the default). If no predicate is given, the factory will always be employed if the correct type is asked for the given item.

If nullIsFallback is set to true the link will continue searching in the chain if the factory returns null.

Parameters

factory:Function — A factory method to create an object for the given item.
 
predicate:Function (default = null) — A predicate method which will return true if the factory should be invoked for the given item. If no predicate is provided, the factory will always be invoked.

Returns
IContextLookupChainLink — The chain link which is created and added to the lookup chain.
setImplementationWrapper()method 
public function setImplementationWrapper(wrapperFactory:Function, predicate:Function = null):IContextLookupChainLink

Creates a chain link which returns an implementation of the asked type which wraps the default (actually the recently added chain link for the same item and implementation type).

The chain link delegates to the given factory method function( item:Object, default:Object ):Object which creates an implementation of the asked type for the given item which wraps the given default implementation.

A predicate function function( item:Object ):Boolean will be queried whether to invoke the factory for the given item or return the default. If no predicate is given, the factory will always be employed if the correct type is asked for the given item.

If decorateNull is set to true a null default will be wrapped, too. Otherwise, null will be returned if the default is null, too.

Parameters

wrapperFactory:Function — The factory method which wraps a given implementation.
 
predicate:Function (default = null) — A function which returns true if the default should be wrapped for the given item. If no predicate is given, the default will always be wrapped.

Returns
IContextLookupChainLink — The chain link which is created and added to the lookup chain.
setInstance()method 
public function setInstance(instance:Object, predicate:Function = null):IContextLookupChainLink

Creates a chain link which returns the given instance when asked for the item and implementation type this LookupDecorator is created for.

This allows to use a shared instance which does not have to be configured for the item.

Developers have to make sure that the object is an implementation of the implementation type this LookupDecorator is created for.

A predicate function function( item:Object ):Boolean will be queried whether to invoke the factory for the given item or return the default. If no predicate is given, the factory will always be employed if the correct type is asked for the given item.

Parameters

instance:Object — The instance to return.
 
predicate:Function (default = null) — A function which returns true if the given instance should be returned for the given item. If no predicate is given, the given instance will always be returned.

Returns
IContextLookupChainLink — The chain link which is created and added to the lookup chain.




Wed Oct 7 2015, 04:52 PM +02:00