Jeff’s blog

http://www.zeuslabs.us/2007/08/19/enforcing-abstract-classes-at-runtime-in-actionscript-3/

看了下他关于用AS3实现的Abstract Class，个人感觉这个实现有点麻烦而且有效率的损失。我试着自己写了一个Abstract Class实现：

抽象类：

[code:php]

package jeff.abstract
{
import flash.errors.IllegalOperationError;

public class MyAbstractClass
{

public function MyAbstractClass(self:MyAbstractClass)
{
if(self != this)
{
throw new IllegalOperationError("Abstract class did not receive reference to self. MyAbstractClass cannot be instantiated directly.");
}
}

public function mustBeOverriden1(param:String):void
{
throw new IllegalOperationError("abstract function must be overriden");
}

public function mustBeOverriden2(param:String):void
{
throw new IllegalOperationError("abstract function must be overriden");
}

}
}

实现类：

package jeff.abstract
{
public class MyImplementClass extends MyAbstractClass
{
public function MyImplementClass()
{
super(this);
}

public override function mustBeOverriden1(param:String):void
{
trace("From or1 "+param);
}

public override function mustBeOverriden2(param:String):void
{
trace("From or2 " + param);
}
}
}

未实现抽象类中的方法的实现类：

package jeff.abstract
{
public class NotImplementAbstract extends MyAbstractClass
{
public function NotImplementAbstract()
{
super(this);
}
}
}

运行类：

package {
import flash.display.Sprite;
import jeff.abstract.MyAbstractClass;
import jeff.abstract.MyImplementClass;
import jeff.abstract.NoImplementAbstract;

public class AbstractTest extends Sprite
{
public function AbstractTest()
{
var a:MyAbstractClass = new MyImplementClass();
a.mustBeOverriden1("hi");
a.mustBeOverriden2("world");

// output: From or1 hi

From or2 world

var b:MyAbstractClass = new NotImplementAbstract();
b.mustBeOverriden1("hi");
b.mustBeOverriden2("world");

// throw exceptions

}
}
}

[/code]
我只是在抽象类中要被抽象的方法中写了个异常抛出语句，意思就是如果你没有覆盖它的话，那么在运行的时候调用这个方法就会抛出异常（并不是像他那样在new的时候就检查是否覆盖了抽象方法）。如果对我这个实现有其它看法的话欢迎评论:)

This entry was posted on Wednesday, August 22nd, 2007 at 10:11 am and is filed under actionscript, oop. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.