Re: [Flashcoders] When singletons go bad
It's a workaround for Flash creating an instance of my component without
running my init() method when the component is dragged onto the stage. I
had posted that problem on here a couple of weeks ago and this solution had
helped prevent from creating a second. I was using the Singleton like from
EAS p 382. If I remember correctly the constructor was being called despite
being private when the component was dragged on the stage- this would result
in a first instance of the class being created without running the line of
code that was setting my _myManager value to reference the class.
On 2/20/06, Isaac Rivera <[EMAIL PROTECTED]> wrote:
>
> I do not understand your implementation of this pattern.
>
> Classically, in single-threaded environments like the flash player,
> Singleton is implemented as below (using your nomenclature):
>
> class MyManager {
> private static _myManager: MyManager = null;
>
> public static function getInstance(): MyManager {
> if(_myManager == null) {
> _myManager = new MyManager();
> }
> return _myManager;
> }
>
> private function MyManager() {
> // constructor stuff here...
> }
> }
>
> This works. I use it regularly.
>
> The strange bit in your code is:
>
> > if(_myManager==null){
> > _myManager=this;
> > }
>
> Since _myManager is a PRIVATE and STATIC property set JUST BEFORE
> calling the constructor the FIRST TIME, why should the constructor
> attempt to set it? Specially when it does so as an instance property
> (ie. Not declaring the Class scope first as in:
>
> MyManager._myManager = this;
>
> What is the advantage of this block?
>
> izk
>
> On Feb 20, 2006, at 9:14 AM, Manuel Saint-Victor wrote:
>
> > Jesse,
> > Here is the getInstance that I am using
> >
> >
> > private function MyManager() {
> > // constructor
> > if(_myManager==null){
> >
> > _myManager=this;
> > }
> >
> > init();
> > }
> >
> > public static function getInstance() : MyManager{
> > if(_myManager==null){
> >
> > _myManager=new MyManager();
> > }
> > return _myManager;
> > }
> >
> >
> >
> > I switched the name of the class a bit but everything else is
> > unchanged in
> > these two methods.
> >
> > Mani
> > ___
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> >
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Re: [Flashcoders] When singletons go bad
I do not understand your implementation of this pattern.
Classically, in single-threaded environments like the flash player,
Singleton is implemented as below (using your nomenclature):
class MyManager {
private static _myManager: MyManager = null;
public static function getInstance(): MyManager {
if(_myManager == null) {
_myManager = new MyManager();
}
return _myManager;
}
private function MyManager() {
// constructor stuff here...
}
}
This works. I use it regularly.
The strange bit in your code is:
if(_myManager==null){
_myManager=this;
}
Since _myManager is a PRIVATE and STATIC property set JUST BEFORE
calling the constructor the FIRST TIME, why should the constructor
attempt to set it? Specially when it does so as an instance property
(ie. Not declaring the Class scope first as in:
MyManager._myManager = this;
What is the advantage of this block?
izk
On Feb 20, 2006, at 9:14 AM, Manuel Saint-Victor wrote:
Jesse,
Here is the getInstance that I am using
private function MyManager() {
// constructor
if(_myManager==null){
_myManager=this;
}
init();
}
public static function getInstance() : MyManager{
if(_myManager==null){
_myManager=new MyManager();
}
return _myManager;
}
I switched the name of the class a bit but everything else is
unchanged in
these two methods.
Mani
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Re: [Flashcoders] When singletons go bad
Only in AS3, not AS2. In AS2: trace ( null == undefined ); // true That's not his problem; that solution works fine. Something else is failing. It's been this way since like Flash 5. - Original Message - From: "Morten Barklund TBWA\Play" <[EMAIL PROTECTED]> To: "Flashcoders mailing list" Sent: Monday, February 20, 2006 9:40 AM Subject: Re: [Flashcoders] When singletons go bad Manuel Saint-Victor wrote: > I had MyManager declared and in my variable declaration chunk up top but > had > not added in the last part(=null) > > private static var _myManager : MyManager; > > I'm going to try changing that and see how if that helps. That would exactly be the problem - as the variable is undefined when not set - never null. Initialising to null or just casting to boolean in the condition should fix the problem. -- Morten Barklund - Information Architect - TBWA\Play Gothersgade 49, 4th floor - DK-1123 Copenhagen K, Denmark Phone: +45 7027 2227 - Fax: +45 3369 1174 ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com
Re: [Flashcoders] When singletons go bad
Manuel Saint-Victor wrote: I had MyManager declared and in my variable declaration chunk up top but had not added in the last part(=null) private static var _myManager : MyManager; I'm going to try changing that and see how if that helps. That would exactly be the problem - as the variable is undefined when not set - never null. Initialising to null or just casting to boolean in the condition should fix the problem. -- Morten Barklund - Information Architect - TBWA\Play Gothersgade 49, 4th floor - DK-1123 Copenhagen K, Denmark Phone: +45 7027 2227 - Fax: +45 3369 1174 ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com
Re: [Flashcoders] When singletons go bad
It's a workaround that someone suggested on the list earlier. Because users
can drag and drop our components in some cases they were getting
instantiated without the static variable being set so they suggested
throwing in that as a way of preventing double instantiation.
I had MyManager declared and in my variable declaration chunk up top but had
not added in the last part(=null)
private static var _myManager : MyManager;
I'm going to try changing that and see how if that helps.
Mani
On 2/20/06, Morten Barklund TBWAPlay <[EMAIL PROTECTED]> wrote:
>
> Manuel Saint-Victor wrote:
> > if(_myManager==null){
>
> Nothing is null, unless explicitly set to null.
>
> And why do you check for the existence of the staticly set _myManager
> both in the static singleton-accessor and in the constructor - one of
> them should be enough.
>
> --
> Morten Barklund - Information Architect - TBWA\Play
> Gothersgade 49, 4th floor - DK-1123 Copenhagen K, Denmark
> Phone: +45 7027 2227 - Fax: +45 3369 1174
> ___
> Flashcoders@chattyfig.figleaf.com
> To change your subscription options or search the archive:
> http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
>
> Brought to you by Fig Leaf Software
> Premier Authorized Adobe Consulting and Training
> http://www.figleaf.com
> http://training.figleaf.com
>
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Re: [Flashcoders] When singletons go bad
Manuel Saint-Victor wrote:
if(_myManager==null){
Nothing is null, unless explicitly set to null.
And why do you check for the existence of the staticly set _myManager
both in the static singleton-accessor and in the constructor - one of
them should be enough.
--
Morten Barklund - Information Architect - TBWA\Play
Gothersgade 49, 4th floor - DK-1123 Copenhagen K, Denmark
Phone: +45 7027 2227 - Fax: +45 3369 1174
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Re: [Flashcoders] When singletons go bad
Jesse,
Here is the getInstance that I am using
private function MyManager() {
// constructor
if(_myManager==null){
_myManager=this;
}
init();
}
public static function getInstance() : MyManager{
if(_myManager==null){
_myManager=new MyManager();
}
return _myManager;
}
I switched the name of the class a bit but everything else is unchanged in
these two methods.
Mani
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Re: [Flashcoders] When singletons go bad
Gotta go for the virus, buddy, ya' can't band-aid it up. That guilt you're feeling is good. Use that frustration to fuel your desire to solve the problem. While you should be commended for finding a solution, it's still just a cover up for the real issue. Post your getInstance method if you can't post the whole class, maybe that will help. - Original Message - From: "Manuel Saint-Victor" <[EMAIL PROTECTED]> To: "Flashcoders mailing list" Sent: Saturday, February 18, 2006 1:16 AM Subject: [Flashcoders] When singletons go bad In my app I have a Singleton that's composed of and manages a video component. In theory- anyone calling the getInstance should be getting that same class and therefore subsequent references to its public properties should be calling the same instanceright? Problem is my getInstances() were not able to control things such as Netstream in that class. Is there some weirdness in having certain aspects be static properties? I ended up finally just pinning them to a namespace on a static class (I'll call the class MJ for now) like this MJ.videoManager and MJ.stateObject it works and I guess it's better than _global(flame off... I know we've had this discussion already) but feels to me that I've negated the benefit of the Singleton if I'm pinning my singleton to the MJ static object and then just going there to find it as other classes need it. Don't get me wrong -it's working and we're happy- but a part of me feels like I took this great pattern used it and then bastardized it. When i try to have other parts of the movie use getInstance to create a reference variable and call methods on it i don't get results. I can't really post code or give a whole bunch of details at this point so I'm trying to describe it the best I can. M ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com
[Flashcoders] When singletons go bad
In my app I have a Singleton that's composed of and manages a video component. In theory- anyone calling the getInstance should be getting that same class and therefore subsequent references to its public properties should be calling the same instanceright? Problem is my getInstances() were not able to control things such as Netstream in that class. Is there some weirdness in having certain aspects be static properties? I ended up finally just pinning them to a namespace on a static class (I'll call the class MJ for now) like this MJ.videoManager and MJ.stateObject it works and I guess it's better than _global(flame off... I know we've had this discussion already) but feels to me that I've negated the benefit of the Singleton if I'm pinning my singleton to the MJ static object and then just going there to find it as other classes need it. Don't get me wrong -it's working and we're happy- but a part of me feels like I took this great pattern used it and then bastardized it. When i try to have other parts of the movie use getInstance to create a reference variable and call methods on it i don't get results. I can't really post code or give a whole bunch of details at this point so I'm trying to describe it the best I can. M ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com
