this link might help. I’m thinking maybe its “different classloaders” ???

http://java.sun.com/developer/technicalArticles/Programming/singletons/

6 classes
GlobalTest_Singleton has a is exactly what it says
GlobalTest_Element is a prototype for an element which is instantiated by an “extends maxobject”
GlobalTest_Sub1Element : type of element to be instantiated inside an “extends maxobject”
GlobalTest_Sub2Element : type of element to be instantiated inside an “extends maxobject”
GlobalTest_Sub1: an “extends maxobject” which instantiates Sub1Element
GlobalTest_Sub2: an “extends maxobject” which instantiates Sub2Element

what I need is for getSingleton() to work in Sub1Element, Sub2Element, Sub1, and Sub2 so that they all reference the same instance of singleton.

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
import com.cycling74.max.*;

public class GlobalTest_Singleton
{
private static GlobalTest_Singleton theonlyone = new GlobalTest_Singleton();

private GlobalTest_Singleton()
{ }

public static GlobalTest_Singleton get_Singleton() {
return theonlyone;
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
import com.cycling74.max.*;

public class GlobalTest_Element
{

public static GlobalTest_Singleton gui = GlobalTest_Singleton.get_Singleton();

public GlobalTest_Element()
{
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
import com.cycling74.max.*;

public class GlobalTest_Sub1Element extends GlobalTest_Element
{

public GlobalTest_Sub1Element()
{
MaxObject.post(“Sub1Element constructor: “+gui);
}

}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
import com.cycling74.max.*;

public class GlobalTest_Sub2Element extends GlobalTest_Element
{
public GlobalTest_Sub2Element()
{
MaxObject.post(“Sub1Element constructor: “+gui);
}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
import com.cycling74.max.*;

public class GlobalTest_Sub1 extends MaxObject
{
private GlobalTest_Sub1Element s=null;

private GlobalTest_Singleton gui2 = GlobalTest_Singleton.get_Singleton();

public GlobalTest_Sub1(Atom[] args)
{
declareInlets(new int[]{DataTypes.ALL});
declareOutlets(new int[]{DataTypes.ALL});

s = new GlobalTest_Sub1Element();
post(“GlobalTest_Sub1 gui= “+s.gui);
post(“GlobalTest_Sub1 gui2= “+gui2);

}
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
import com.cycling74.max.*;

public class GlobalTest_Sub2 extends MaxObject
{
private GlobalTest_Singleton gui2 = GlobalTest_Singleton.get_Singleton();

private GlobalTest_Sub2Element s=null;

public GlobalTest_Sub2(Atom[] args)
{
declareInlets(new int[]{DataTypes.ALL});
declareOutlets(new int[]{DataTypes.ALL});

s = new GlobalTest_Sub2Element();
post(“GlobalTest_Sub2 gui= “+s.gui);
post(“GlobalTest_Sub2 gui2= “+gui2);
}
}

>From a glance at your code, it would seem to be a correct
implementation of one of the ways of implementing a Singleton. Deos it
work when you test it?

The other approach is to declare the single instance final:

public class Benedict {
public static final Benedict INSTANCE = new Benedict();

private Benedict() {
…
}

… // etc.
}

The static factory method you use is more flexible, though perhaps
minimally less efficient (or so say the books I’ve been reading).

I guess the real question is what you want to use it
for…constructing a gui sounds a little odd, but I don’t know the
circumstances. A great book for getting started with design patterns
(among them the singleton) is O’Reilly’s Head First Design Patterns.
Also has an innovative approach to design itself.

– Paul

On 5/3/07, Matthew Aidekman wrote:
>
> Ok I’m going to try and explain this as succinctly as possible. it may be a brain teaser. I’m a beginner javamaxer. In fact I just learned what a singleton was. What I’m doing in reality is editing the Java JitterGui. but I’ve mangled it pretty fearsome. I’m thinking what I need is an ?interface? of some sort.
>
> this link might help. I’m thinking maybe its “different classloaders” ???
> http://java.sun.com/developer/technicalArticles/Programming/singletons/
>
>
> 6 classes
> GlobalTest_Singleton has a is exactly what it says
> GlobalTest_Element is a prototype for an element which is instantiated by an “extends maxobject”
> GlobalTest_Sub1Element : type of element to be instantiated inside an “extends maxobject”
> GlobalTest_Sub2Element : type of element to be instantiated inside an “extends maxobject”
> GlobalTest_Sub1: an “extends maxobject” which instantiates Sub1Element
> GlobalTest_Sub2: an “extends maxobject” which instantiates Sub2Element
>
>
> what I need is for getSingleton() to work in Sub1Element, Sub2Element, Sub1, and Sub2 so that they all reference the same instance of singleton.
>
>
>
> //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> import com.cycling74.max.*;
>
> public class GlobalTest_Singleton
> {
> private static GlobalTest_Singleton theonlyone = new GlobalTest_Singleton();
>
> private GlobalTest_Singleton()
> { }
>
> public static GlobalTest_Singleton get_Singleton() {
> return theonlyone;
> }
> }
> //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> import com.cycling74.max.*;
>
> public class GlobalTest_Element
> {
>
> public static GlobalTest_Singleton gui = GlobalTest_Singleton.get_Singleton();
>
> public GlobalTest_Element()
> {
> }
> }
> //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> import com.cycling74.max.*;
>
> public class GlobalTest_Sub1Element extends GlobalTest_Element
> {
>
> public GlobalTest_Sub1Element()
> {
> MaxObject.post(“Sub1Element constructor: “+gui);
> }
>
> }
> //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> import com.cycling74.max.*;
>
> public class GlobalTest_Sub2Element extends GlobalTest_Element
> {
> public GlobalTest_Sub2Element()
> {
> MaxObject.post(“Sub1Element constructor: “+gui);
> }
> }
> //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> import com.cycling74.max.*;
>
> public class GlobalTest_Sub1 extends MaxObject
> {
> private GlobalTest_Sub1Element s=null;
>
> private GlobalTest_Singleton gui2 = GlobalTest_Singleton.get_Singleton();
>
> public GlobalTest_Sub1(Atom[] args)
> {
> declareInlets(new int[]{DataTypes.ALL});
> declareOutlets(new int[]{DataTypes.ALL});
>
> s = new GlobalTest_Sub1Element();
> post(“GlobalTest_Sub1 gui= “+s.gui);
> post(“GlobalTest_Sub1 gui2= “+gui2);
>
> }
> }
> //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
> import com.cycling74.max.*;
>
> public class GlobalTest_Sub2 extends MaxObject
> {
> private GlobalTest_Singleton gui2 = GlobalTest_Singleton.get_Singleton();
>
> private GlobalTest_Sub2Element s=null;
>
> public GlobalTest_Sub2(Atom[] args)
> {
> declareInlets(new int[]{DataTypes.ALL});
> declareOutlets(new int[]{DataTypes.ALL});
>
> s = new GlobalTest_Sub2Element();
> post(“GlobalTest_Sub2 gui= “+s.gui);
> post(“GlobalTest_Sub2 gui2= “+gui2);
> }
> }
>
>

–
—– |(*,+,#,=)(#,=,*,+)(=,#,+,*)(+,*,=,#)| —–

when I instantiate sub1 and sub2, this is what appears in the max window. each SubElement appears to be in its own world where singleton must be reinstantiated. I would assume this is expected behaviour and its my “fault.”

Sub1Element constructor: GlobalTest_Singleton@7e6081
GlobalTest_Sub1 gui= GlobalTest_Singleton@7e6081
GlobalTest_Sub1 gui2= GlobalTest_Singleton@7e6081
Sub1Element constructor: GlobalTest_Singleton@fff2dc
GlobalTest_Sub2 gui= GlobalTest_Singleton@fff2dc
GlobalTest_Sub2 gui2= GlobalTest_Singleton@fff2dc

Ollie

On 4 May 2007, at 07:21, Matthew Aidekman wrote:

> I’ve uploaded a set of files with this exact code.
>
> when I instantiate sub1 and sub2, this is what appears in the max
> window. each SubElement appears to be in its own world where
> singleton must be reinstantiated. I would assume this is expected
> behaviour and its my “fault.”
>
> Sub1Element constructor: GlobalTest_Singleton@7e6081
> GlobalTest_Sub1 gui= GlobalTest_Singleton@7e6081
> GlobalTest_Sub1 gui2= GlobalTest_Singleton@7e6081
> Sub1Element constructor: GlobalTest_Singleton@fff2dc
> GlobalTest_Sub2 gui= GlobalTest_Singleton@fff2dc
> GlobalTest_Sub2 gui2= GlobalTest_Singleton@fff2dc
>
>

If I simultaneously ‘zap’ your two classes, or if one of the class
files is recompiled and the object then reloaded, then they do start
to report different singletons, which makes sense in light of the
above article. Presumably the MXJClassLoader for each class also
looks after the classes being referenced by it, resulting in two
GlobalTest_Singleton classes.

I’m doing stuff with static variables being used across a set of
classes too, and boring though it is, I’ve always felt safer quitting
and restarting Max when I really want to be sure that something
static is doing what I expected it to do. But now I’m curious,
presumably you can make your own MXJClassLoader and force it to load
a specified set of classes, or a package. Hmmm.

Ollie

On 4 May 2007, at 09:14, Oliver Bown wrote:

> I ran your classes and got the behaviour you wanted (the expected
> behaviour) rather than the behaviour you report. Everything is
> pointing to the same GlobalTest_Singleton. Looks like your code is
> fine but your test patch is doing something funny. Are you zapping
> or something?
>
> Ollie
>
> On 4 May 2007, at 07:21, Matthew Aidekman wrote:
>
>> I’ve uploaded a set of files with this exact code.
>>
>> when I instantiate sub1 and sub2, this is what appears in the max
>> window. each SubElement appears to be in its own world where
>> singleton must be reinstantiated. I would assume this is expected
>> behaviour and its my “fault.”
>>
>> Sub1Element constructor: GlobalTest_Singleton@7e6081
>> GlobalTest_Sub1 gui= GlobalTest_Singleton@7e6081
>> GlobalTest_Sub1 gui2= GlobalTest_Singleton@7e6081
>> Sub1Element constructor: GlobalTest_Singleton@fff2dc
>> GlobalTest_Sub2 gui= GlobalTest_Singleton@fff2dc
>> GlobalTest_Sub2 gui2= GlobalTest_Singleton@fff2dc
>>
>>
>

What version of Max are you on? Under an older classloading scheme, this
approach wouldn’t work at all. Under the current one, it should, but
you’re well off closing and opening the patch, or zapping everything, or
even restarting max to make sure everything’s loaded from the same
classloader.

–
Owen

Matthew Aidekman wrote:
> Ok I’m going to try and explain this as succinctly as possible. it
> may be a brain teaser. I’m a beginner javamaxer. In fact I just
> learned what a singleton was. What I’m doing in reality is editing
> the Java JitterGui. but I’ve mangled it pretty fearsome. I’m
> thinking what I need is an ?interface? of some sort.

I will look into classloader zap etc..

you guys rock. I can’t believe someone actually tested that gobblety gook.

Given that you’re up to date mxj-wise, can you verify Ollie’s experience
that it works if you restart max? All instances should then share a
classloader, and static behaviour should work across objects.

–
Owen

/looking into zap

unfortunately, I’m just not at that level yet. I looked up classloader, I don’t understand it. but I will make my way through it more slowly.

O

On 4 May 2007, at 17:35, Matthew Aidekman wrote:

>
> ollie, if you figure that thing out with the classloaders, please
> let me know, I’m planning on scripting these objects in and out
> of existence so it would be very helpful.
>
> unfortunately, I’m just not at that level yet. I looked up
> classloader, I don’t understand it. but I will make my way through
> it more slowly.