[we're not talking about those mirror-images that were hip in Flash for a year.] reflection allows your code to inspect its own properties, methods, type, parent-type… . used in recipes including copying xml values to object properties & creating a decorator which extends proxy. I’m putting useful examples below, in one convient spot.
ReflectionUtil.rtf includes:
inspecting an Object internally
- returning the public instance properties/methods of an Object.
- copying/duplicating public instance properties between Objects.
//----------------------------------------------------------------------------
// Methods which inspect the public instance properties/methods of an Object
//----------------------------------------------------------------------------
/**
* locates the public props of $obj
* @param $obj: the object to inspect.
* @param nodeName: 'variable' grabs properties, 'method' grabs methods
* @return: dictionary of nodes in $obj identified by nodeName
*/
public static const VARIABLE:String = 'variable';
public static const METHOD:String = 'method';
public static function findPublic($obj:*, nodeName:String=VARIABLE):Dictionary
{
var dict:Dictionary = new Dictionary(true);
var nodeList:XMLList;
switch (nodeName)
{
case VARIABLE:
nodeList = describeType($obj)..variable;
break;
case METHOD:
nodeList = describeType($obj)..method;
break;
default:
throw new Error('node label is not handled.');
}
var n:int=nodeList.length();
for(var i:int = 0; i < n; i++)
{
dict[String(nodeList[i].@name)] = true;
}
nodeList = null;
return dict;
}
/**
* sets public properties of parent object equal to matching properties of $obj
* @param $obj: object whose matching name/type properties will be
* duplicated (primitives) or pointed to (complex data types)
* @param cloneData
*/
public static function propsFromObject(copyFrom:*, copyTo:*, cloneData:Boolean=false):void
{
var varList:XMLList = describeType(copyTo)..variable;
var n:int=varList.length();
for(var i:int=0; i < n; i++)
{
var prop:String = String(varList[i].@name);
if (copyFrom.hasOwnProperty(prop))
{
copyTo[prop] = (cloneData) ? returnNewRef(copyFrom[prop], varList[i].@type) : copyFrom[prop];
}
}
varList=null;
}
/**
* used by propsFromObject if a new instance of the copied property is desired.
* create additional cases as needed.
* @param prop: the value being duplicated
* @param type: the value's type
* @return: a new instance of the value
* @throws Error: if attempting to duplicate an Object which is not handled
*/
private static function returnNewRef(prop:*, type:*):*
{
var cloneProp:*;
switch (String(type))
{
case "Array":
cloneProp = new Array().concat((prop as Array));
break;
case "flash.display::Bitmap":
cloneProp = new Bitmap((prop as Bitmap).bitmapData);
break;
case "Number":
case "int":
case "uint":
case "String":
case "Boolean":
case "Null":
case "void":
cloneProp = prop;
break;
default:
throw new Error('returnNewRef:: create instantiation for '+type);
}
return cloneProp;
}
// Methods which inspect the public instance properties/methods of an Object
//----------------------------------------------------------------------------
/**
* locates the public props of $obj
* @param $obj: the object to inspect.
* @param nodeName: 'variable' grabs properties, 'method' grabs methods
* @return: dictionary of nodes in $obj identified by nodeName
*/
public static const VARIABLE:String = 'variable';
public static const METHOD:String = 'method';
public static function findPublic($obj:*, nodeName:String=VARIABLE):Dictionary
{
var dict:Dictionary = new Dictionary(true);
var nodeList:XMLList;
switch (nodeName)
{
case VARIABLE:
nodeList = describeType($obj)..variable;
break;
case METHOD:
nodeList = describeType($obj)..method;
break;
default:
throw new Error('node label is not handled.');
}
var n:int=nodeList.length();
for(var i:int = 0; i < n; i++)
{
dict[String(nodeList[i].@name)] = true;
}
nodeList = null;
return dict;
}
/**
* sets public properties of parent object equal to matching properties of $obj
* @param $obj: object whose matching name/type properties will be
* duplicated (primitives) or pointed to (complex data types)
* @param cloneData
*/
public static function propsFromObject(copyFrom:*, copyTo:*, cloneData:Boolean=false):void
{
var varList:XMLList = describeType(copyTo)..variable;
var n:int=varList.length();
for(var i:int=0; i < n; i++)
{
var prop:String = String(varList[i].@name);
if (copyFrom.hasOwnProperty(prop))
{
copyTo[prop] = (cloneData) ? returnNewRef(copyFrom[prop], varList[i].@type) : copyFrom[prop];
}
}
varList=null;
}
/**
* used by propsFromObject if a new instance of the copied property is desired.
* create additional cases as needed.
* @param prop: the value being duplicated
* @param type: the value's type
* @return: a new instance of the value
* @throws Error: if attempting to duplicate an Object which is not handled
*/
private static function returnNewRef(prop:*, type:*):*
{
var cloneProp:*;
switch (String(type))
{
case "Array":
cloneProp = new Array().concat((prop as Array));
break;
case "flash.display::Bitmap":
cloneProp = new Bitmap((prop as Bitmap).bitmapData);
break;
case "Number":
case "int":
case "uint":
case "String":
case "Boolean":
case "Null":
case "void":
cloneProp = prop;
break;
default:
throw new Error('returnNewRef:: create instantiation for '+type);
}
return cloneProp;
}
inspecting an Object type
- checking whether two Objects are the same type
- checking whether an Object extends another
//--------------------------------------
// Methods which inspect Class names
//--------------------------------------
/**
* checks whether two classes are of the same type
* @param compareThis
* @param toThis
* @return
*/
public static function getIsSameType(compareThis:*,toThis:*):Boolean
{
return (getClassName(compareThis) == getClassName(toThis));
}
/**
* @param classIn
* @return: the class name as String
*/
public static function getClassName(classIn:*):String
{
/* === flash.utils.getQualifiedClassName(classIn).split("::")[1] */
return describeType(classIn).@name.split("::")[1];
}
/**
* checks whether one class is a child of another
* @param doesThis: the possible child
* @param extendThis: the possible parent
* @return
*/
public static function getDoesExtend(doesThis:*,extendThis:*):Boolean
{
var doesExtend:Boolean=false;
var extendsL:XMLList = describeType(doesThis).extendsClass;
var toThisClassName:String = getClassName(extendThis);
for each( var i:XML in extendsL)
{
if (i.@type.split("::")[1]==toThisClassName)
{
doesExtend=true;
break;
}
}
extendsL=null;
return doesExtend;
}
// Methods which inspect Class names
//--------------------------------------
/**
* checks whether two classes are of the same type
* @param compareThis
* @param toThis
* @return
*/
public static function getIsSameType(compareThis:*,toThis:*):Boolean
{
return (getClassName(compareThis) == getClassName(toThis));
}
/**
* @param classIn
* @return: the class name as String
*/
public static function getClassName(classIn:*):String
{
/* === flash.utils.getQualifiedClassName(classIn).split("::")[1] */
return describeType(classIn).@name.split("::")[1];
}
/**
* checks whether one class is a child of another
* @param doesThis: the possible child
* @param extendThis: the possible parent
* @return
*/
public static function getDoesExtend(doesThis:*,extendThis:*):Boolean
{
var doesExtend:Boolean=false;
var extendsL:XMLList = describeType(doesThis).extendsClass;
var toThisClassName:String = getClassName(extendThis);
for each( var i:XML in extendsL)
{
if (i.@type.split("::")[1]==toThisClassName)
{
doesExtend=true;
break;
}
}
extendsL=null;
return doesExtend;
}
