Example: Adding States and Identifying Users | 297duplicate=false;
for(var ob=0;ob<this.observers.length;ob++)
{
if(this.observers[ob]==obserNow)
{
duplicate=true;
trace( this.observers[ob].subName+ " already a subscriber.
\n");
}
}
if(! duplicate)
{
this.observers.push(obserNow);
}
}In some cases, you may not want to limit single subscriptions with a common name.
To allow multiple subscribers with the same name, just don’t add the above code
that prevents doing so.
Updated Observer
Now the Observer application has far more functionality. Not only can each
observer be identified by a specific name, no more than a single observer with the
same name will be allowed to subscribe. What’s more, four states are now tracked
and sent out if changed. Example 8-10 through Example 8-13 should be saved in the
same folder using the captions for the filenames.
Example 8-10. Subject.as
package
{
//Subject Interface
public interface Subject
{
function subscribeObserver(o:Observer):void;
function unsubscribeObserver(o:Observer):void;
function notifyObserver( ):void;
}
}
Example 8-11. Observer.as
package
{
//Observer Interface
public interface Observer
{
function update(news:String,sports:String,stocks:Number,entertainment:
String):void;
}
}