as 中的反射 describeType

describeType函数在adobe官方在线文档上的定义如下：生成描述ActionScript对象(命令为方法的参数)的XML对象，此方法实现ActionScript语言的反射编程概念。

这个方法的应用场景可能是这样的：

定义一个方法，解析很多邮件的消息，很多消息的内容格式又是一致的(需要实现方法的共用)，那么定义下面一系列的方法了。

public function parseEmail_1():void {}

public function parseEmail_2_3_4_5():void {}

public function parseEmail_10_11_12():void {}

…

如何根据邮件格式的消息，直接就调用了相应的函数？那首先需要有一个对象存储了该类的所有方法，然后查找到包含此id的方法，之后调用它即可。

当参数为对象的时候,则返回的 XML 对象包括该类型的所有实例属性，但不包括任何静态属性。.isStatic属性为flase

当参数为类的时候,返回的 XML 对象不仅仅包括类型的静态属性，而且还包括它的所有实例属性。 实例属性嵌套在名为 <factory> 的标签内，从而与静态属性区分开来。 在这种情况下，<type> 标签的 isStatic 属性为 true。

accessor  属性

method  方法

示例：

建立一个名为“describeType_Test”的ActionScript工程。使用describeType(类名)即可获得到该类的所有相关信息

<type name="describeType_Test" base="Class" isDynamic="true" isFinal="true" isStatic="true">
  <extendsClass type="Class"/>
  <extendsClass type="Object"/>
  <accessor name="prototype" access="readonly" type="*" declaredBy="Class"/>
  <factory type="describeType_Test">
    <extendsClass type="flash.display::Sprite"/>
    <extendsClass type="flash.display::DisplayObjectContainer"/>
    <extendsClass type="flash.display::InteractiveObject"/>
    <extendsClass type="flash.display::DisplayObject"/>
    <extendsClass type="flash.events::EventDispatcher"/>
    <extendsClass type="Object"/>
    <implementsInterface type="flash.events::IEventDispatcher"/>
    <implementsInterface type="flash.display::IBitmapDrawable"/>
    <accessor name="useHandCursor" access="readwrite" type="Boolean" declaredBy="flash.display::Sprite"/>
    <accessor name="root" access="readonly" type="flash.display::DisplayObject" declaredBy="flash.display::DisplayObject"/>
    <accessor name="stage" access="readonly" type="flash.display::Stage" declaredBy="flash.display::DisplayObject"/>
    <accessor name="mask" access="readwrite" type="flash.display::DisplayObject" declaredBy="flash.display::DisplayObject"/>
    <accessor name="width" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="visible" access="readwrite" type="Boolean" declaredBy="flash.display::DisplayObject"/>
    <accessor name="alpha" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="height" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="mouseY" access="readonly" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="rotation" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="mouseX" access="readonly" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="mouseEnabled" access="readwrite" type="Boolean" declaredBy="flash.display::InteractiveObject"/>
    <accessor name="tabIndex" access="readwrite" type="int" declaredBy="flash.display::InteractiveObject"/>
    <accessor name="doubleClickEnabled" access="readwrite" type="Boolean" declaredBy="flash.display::InteractiveObject"/>
    <accessor name="focusRect" access="readwrite" type="Object" declaredBy="flash.display::InteractiveObject"/>
    <accessor name="y" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="cacheAsBitmap" access="readwrite" type="Boolean" declaredBy="flash.display::DisplayObject"/>
    <accessor name="x" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="opaqueBackground" access="readwrite" type="Object" declaredBy="flash.display::DisplayObject"/>
    <accessor name="accessibilityImplementation" access="readwrite" type="flash.accessibility::AccessibilityImplementation" declaredBy="flash.display::InteractiveObject">
      <metadata name="Inspectable">
        <arg key="environment" value="none"/>
      </metadata>
    </accessor>
    <accessor name="scrollRect" access="readwrite" type="flash.geom::Rectangle" declaredBy="flash.display::DisplayObject"/>
    <accessor name="filters" access="readwrite" type="Array" declaredBy="flash.display::DisplayObject"/>
    <accessor name="blendMode" access="readwrite" type="String" declaredBy="flash.display::DisplayObject"/>
    <accessor name="transform" access="readwrite" type="flash.geom::Transform" declaredBy="flash.display::DisplayObject"/>
    <accessor name="name" access="readwrite" type="String" declaredBy="flash.display::DisplayObject"/>
    <accessor name="scale9Grid" access="readwrite" type="flash.geom::Rectangle" declaredBy="flash.display::DisplayObject"/>
    <accessor name="loaderInfo" access="readonly" type="flash.display::LoaderInfo" declaredBy="flash.display::DisplayObject"/>
    <accessor name="accessibilityProperties" access="readwrite" type="flash.accessibility::AccessibilityProperties" declaredBy="flash.display::DisplayObject"/>
    <accessor name="contextMenu" access="readwrite" type="flash.ui::ContextMenu" declaredBy="flash.display::InteractiveObject"/>
    <accessor name="soundTransform" access="readwrite" type="flash.media::SoundTransform" declaredBy="flash.display::Sprite"/>
    <accessor name="parent" access="readonly" type="flash.display::DisplayObjectContainer" declaredBy="flash.display::DisplayObject"/>
    <accessor name="numChildren" access="readonly" type="int" declaredBy="flash.display::DisplayObjectContainer"/>
    <accessor name="dropTarget" access="readonly" type="flash.display::DisplayObject" declaredBy="flash.display::Sprite"/>
    <accessor name="tabEnabled" access="readwrite" type="Boolean" declaredBy="flash.display::InteractiveObject"/>
    <accessor name="hitArea" access="readwrite" type="flash.display::Sprite" declaredBy="flash.display::Sprite"/>
    <accessor name="scaleX" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="graphics" access="readonly" type="flash.display::Graphics" declaredBy="flash.display::Sprite"/>
    <accessor name="scaleY" access="readwrite" type="Number" declaredBy="flash.display::DisplayObject"/>
    <accessor name="textSnapshot" access="readonly" type="flash.text::TextSnapshot" declaredBy="flash.display::DisplayObjectContainer"/>
    <accessor name="buttonMode" access="readwrite" type="Boolean" declaredBy="flash.display::Sprite"/>
    <accessor name="tabChildren" access="readwrite" type="Boolean" declaredBy="flash.display::DisplayObjectContainer"/>
    <accessor name="mouseChildren" access="readwrite" type="Boolean" declaredBy="flash.display::DisplayObjectContainer"/>
    <method name="swapChildren" declaredBy="flash.display::DisplayObjectContainer" returnType="void">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
      <parameter index="2" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="startDrag" declaredBy="flash.display::Sprite" returnType="void">
      <parameter index="1" type="Boolean" optional="true"/>
      <parameter index="2" type="flash.geom::Rectangle" optional="true"/>
    </method>
    <method name="stopDrag" declaredBy="flash.display::Sprite" returnType="void"/>
    <method name="removeEventListener" declaredBy="flash.events::EventDispatcher" returnType="void">
      <parameter index="1" type="String" optional="false"/>
      <parameter index="2" type="Function" optional="false"/>
      <parameter index="3" type="Boolean" optional="true"/>
    </method>
    <method name="parseEmail_13_14_1115" declaredBy="describeType_Test" returnType="void"/>
    <method name="addEventListener" declaredBy="flash.events::EventDispatcher" returnType="void">
      <parameter index="1" type="String" optional="false"/>
      <parameter index="2" type="Function" optional="false"/>
      <parameter index="3" type="Boolean" optional="true"/>
      <parameter index="4" type="int" optional="true"/>
      <parameter index="5" type="Boolean" optional="true"/>
    </method>
    <method name="parseEmail_10_101_112" declaredBy="describeType_Test" returnType="void"/>
    <method name="parseEmail_2" declaredBy="describeType_Test" returnType="void"/>
    <method name="willTrigger" declaredBy="flash.events::EventDispatcher" returnType="Boolean">
      <parameter index="1" type="String" optional="false"/>
    </method>
    <method name="dispatchEvent" declaredBy="flash.events::EventDispatcher" returnType="Boolean">
      <parameter index="1" type="flash.events::Event" optional="false"/>
    </method>
    <method name="hasEventListener" declaredBy="flash.events::EventDispatcher" returnType="Boolean">
      <parameter index="1" type="String" optional="false"/>
    </method>
    <method name="parseEmail_3" declaredBy="describeType_Test" returnType="void"/>
    <method name="toString" declaredBy="flash.events::EventDispatcher" returnType="String"/>
    <method name="parseEmail_1" declaredBy="describeType_Test" returnType="void"/>
    <method name="globalToLocal" declaredBy="flash.display::DisplayObject" returnType="flash.geom::Point">
      <parameter index="1" type="flash.geom::Point" optional="false"/>
    </method>
    <method name="localToGlobal" declaredBy="flash.display::DisplayObject" returnType="flash.geom::Point">
      <parameter index="1" type="flash.geom::Point" optional="false"/>
    </method>
    <method name="getBounds" declaredBy="flash.display::DisplayObject" returnType="flash.geom::Rectangle">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="addChildAt" declaredBy="flash.display::DisplayObjectContainer" returnType="flash.display::DisplayObject">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
      <parameter index="2" type="int" optional="false"/>
    </method>
    <method name="getRect" declaredBy="flash.display::DisplayObject" returnType="flash.geom::Rectangle">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="removeChild" declaredBy="flash.display::DisplayObjectContainer" returnType="flash.display::DisplayObject">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="addChild" declaredBy="flash.display::DisplayObjectContainer" returnType="flash.display::DisplayObject">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="removeChildAt" declaredBy="flash.display::DisplayObjectContainer" returnType="flash.display::DisplayObject">
      <parameter index="1" type="int" optional="false"/>
    </method>
    <method name="contains" declaredBy="flash.display::DisplayObjectContainer" returnType="Boolean">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="hitTestObject" declaredBy="flash.display::DisplayObject" returnType="Boolean">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="getChildIndex" declaredBy="flash.display::DisplayObjectContainer" returnType="int">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
    </method>
    <method name="hitTestPoint" declaredBy="flash.display::DisplayObject" returnType="Boolean">
      <parameter index="1" type="Number" optional="false"/>
      <parameter index="2" type="Number" optional="false"/>
      <parameter index="3" type="Boolean" optional="true"/>
    </method>
    <method name="setChildIndex" declaredBy="flash.display::DisplayObjectContainer" returnType="void">
      <parameter index="1" type="flash.display::DisplayObject" optional="false"/>
      <parameter index="2" type="int" optional="false"/>
    </method>
    <method name="getChildByName" declaredBy="flash.display::DisplayObjectContainer" returnType="flash.display::DisplayObject">
      <parameter index="1" type="String" optional="false"/>
    </method>
    <method name="getChildAt" declaredBy="flash.display::DisplayObjectContainer" returnType="flash.display::DisplayObject">
      <parameter index="1" type="int" optional="false"/>
    </method>
    <method name="parseEmail_4_5_6_7" declaredBy="describeType_Test" returnType="void"/>
    <method name="getObjectsUnderPoint" declaredBy="flash.display::DisplayObjectContainer" returnType="Array">
      <parameter index="1" type="flash.geom::Point" optional="false"/>
    </method>
    <method name="areInaccessibleObjectsUnderPoint" declaredBy="flash.display::DisplayObjectContainer" returnType="Boolean">
      <parameter index="1" type="flash.geom::Point" optional="false"/>
    </method>
    <method name="swapChildrenAt" declaredBy="flash.display::DisplayObjectContainer" returnType="void">
      <parameter index="1" type="int" optional="false"/>
      <parameter index="2" type="int" optional="false"/>
    </method>
  </factory>
</type>

这样，只需要获取到该xml对象下的所有method节点，然后遍历它，匹配到包含该邮件格式id的方法，使用split将方法名分隔开：parseEmail、1、2、…，第一位则为方法名，之后的便是该方法可以解析的指定格式的id，调用this[funName](paras..);

 

as的示例代码：

package
{
    import flash.display.Sprite;
    import flash.utils.describeType;
    import flash.utils.getDefinitionByName;
    import flash.utils.getQualifiedClassName;
    import flash.utils.getQualifiedSuperclassName;

    public class describeType_Test extends Sprite
    {
        public function describeType_Test()
        {
            //this [object describeType_Test]
            var clsStr:String = getQualifiedClassName(this);    //describeType_Test
            var supClsStr:String = getQualifiedSuperclassName(this);    //flash.display::Sprite

            var cls:Class = getDefinitionByName(clsStr) as Class;

            var xml:XML = describeType(cls);

            trace(xml);
        }

        public function parseEmail_1():void
        {

        }

        public function parseEmail_2():void
        {

        }

        public function parseEmail_3():void
        {

        }

        public function parseEmail_4_5_6_7():void
        {

        }

        public function parseEmail_10_101_112():void
        {

        }

        public function parseEmail_13_14_1115():void
        {

        }

    }
}