Deprecated metadata tag

用法：
[Deprecated("string_describing_deprecation")]
[Deprecated(message="string_describing_deprecation")]
[Deprecated(replacement="string_specifying_replacement")]
[Deprecated(replacement="string_specifying_replacement", since="version_of_replacement")]

原文(引用自adobe flex4 help)：
A class or class element marked as deprecated is one which is considered obsolete, and whose use is discouraged in the current release. While the class or class element still works, its use can generate compiler warnings

一個類別或是類別中的項目被標記成Deprecated表示此項目是過時的、廢棄的、不建議使用的，不鼓勵使用在當前的釋出版本。雖然被宣告廢棄的Class或Class中的項目仍然工作，但能讓編譯器產生警告提醒。

The mxmlc command-line compiler supports the show-deprecation-warnings compiler option, which, when true, configures the compiler to issue deprecation warnings when your application uses deprecated elements. The default value is true.

Insert the [Deprecated] metadata tag before a property, method, or class definition to mark that element as deprecated. The [Deprecated] metadata tag has the following options for its syntax when used with a class, property or method:
 
功用：

• 標記已經廢棄的Class以免誤用，若使用編譯器會出現警告提醒。

範例：
//宣告method已經廢棄，並提示改用建議的method

package com
{
　import spark.components.Group;
　public class MyDeprecatedGroup extends Group
　{
　　public function MyDeprecatedGroup()
　　{
　　　super();
　　}　　
　　private var _topGap:Number; 
　　//宣告topGap廢棄,並建議使用topPixels
　　[Deprecated(replacement="MyDeprecatedGroup.topPixels")] 
　　public function set topGap(value:Number):void
　　{
　　　_topGap = value;
　　}
　　public function get topGap():Number
　　{
　　　return _topGap;
　　}
　}
}  

//Application

<?xml version="1.0" encoding="utf-8"?> 
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
xmlns:s="library://ns.adobe.com/flex/spark" 
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"
applicationComplete="application1_applicationCompleteHandler(event)" xmlns:com="com.*"
>
<fx:Script\>
<![CDATA[ 
]]>
</fx:Script>
<com:MyDeprecatedGroup>
　<com:topGap>1.0</com:topGap>  
</com:MyDeprecatedGroup>
</s:Application>   

訊息警告如下圖：
 

 
 
 
 
 

• Event,Effect,Style,metadata tags也支援 deprecation功能

文件
The [Event], [Effect] and [Style] metadata tags also support deprecation. These tags support the following options for syntax:
 
在Event,Effect,Style的metadata tags中，也都支持deprecation的宣告,用法如下
 
用法
[Event(... , deprecatedMessage="string_describing_deprecation")]
[Event(... , deprecatedReplacement="change2")]
[Event(... , deprecatedReplacement="string_specifying_replacement", deprecatedSince="version_of_replacement")]