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Database implementation of java.util.prefs.Preferences?

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  Database implementation of java.util.prefs.Preferences? Marcin <nomail@nospam.com> - 2012-09-19 22:51 +0200
    Re: Database implementation of java.util.prefs.Preferences? markspace <-@.> - 2012-09-19 15:28 -0700
      Re: Database implementation of java.util.prefs.Preferences? "John B. Matthews" <nospam@nospam.invalid> - 2012-09-19 20:59 -0400
        Re: Database implementation of java.util.prefs.Preferences? markspace <-@.> - 2012-09-19 19:07 -0700
          Re: Database implementation of java.util.prefs.Preferences? "John B. Matthews" <nospam@nospam.invalid> - 2012-09-20 12:20 -0400
    Re: Database implementation of java.util.prefs.Preferences? Roedy Green <see_website@mindprod.com.invalid> - 2012-09-21 07:12 -0700
      Re: Database implementation of java.util.prefs.Preferences? "John B. Matthews" <nospam@nospam.invalid> - 2012-09-21 21:10 -0400
    Re: Database implementation of java.util.prefs.Preferences? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-09-21 10:19 -0700

#2094 — Database implementation of java.util.prefs.Preferences?

Hello

I have a Java program that uses java.util.prefs.Preferences to store 
configuration data. Everything is OK if one user works on one computer 
but if one user can use many computers the data is not shared between 
workstations and "environment" is different dependent on which computer 
user is logged in. I think I can store the same data in database because 
application uses connection to database for other purposes. Do you know 
any implementation of abstract class java.util.prefs.Preferences  that 
uses SQL to store the configuration data? I cannot google anything 
interesting...

Regards,
Mar

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#2095

On 9/19/2012 1:51 PM, Marcin wrote:
>
> I have a Java program that uses java.util.prefs.Preferences to store
> configuration data. Everything is OK if one user works on one computer
> but if one user can use many computers the data is not shared between
> workstations and "environment" is different dependent on which computer
> user is logged in. I think I can store the same data in database because
> application uses connection to database for other purposes. Do you know
> any implementation of abstract class java.util.prefs.Preferences  that
> uses SQL to store the configuration data? I cannot google anything


I would kind of doubt there is one.  In a situation like this, I would 
consider using Preferences::exportSubtree() and 
Preferences::importPreferences() to read and write to a blob in a 
database.

I'd think carefully about it first though, as something about it feels 
like a mismatch for a preferences module in general.

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#2096

In article <k3dgu8$k1h$1@dont-email.me>, markspace <-@.> wrote:

> On 9/19/2012 1:51 PM, Marcin wrote:
> >
> > I have a Java program that uses java.util.prefs.Preferences to 
> > store configuration data. Everything is OK if one user works on one 
> > computer but if one user can use many computers the data is not 
> > shared between workstations and "environment" is different 
> > dependent on which computer user is logged in. I think I can store 
> > the same data in database because application uses connection to 
> > database for other purposes. Do you know any implementation of 
> > abstract class java.util.prefs.Preferences  that uses SQL to store 
> > the configuration data? I cannot google anything
> 
> 
> I would kind of doubt there is one.  In a situation like this, I 
> would consider using Preferences::exportSubtree() and 
> Preferences::importPreferences() to read and write to a blob in a 
> database.
> 
> I'd think carefully about it first though, as something about it 
> feels like a mismatch for a preferences module in general.

"There are two separate trees of preference nodes, one for user 
preferences and one for system preferences." Instead of SQL, just start 
from systemRoot() for shared preferences.

<http://docs.oracle.com/javase/7/docs/api/java/util/prefs/Preferences.html>

-- 
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>

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#2097

On 9/19/2012 5:59 PM, John B. Matthews wrote:
> In article <k3dgu8$k1h$1@dont-email.me>, markspace <-@.> wrote:
>
>> On 9/19/2012 1:51 PM, Marcin wrote:
>>> if one user can use many computers the data is not
>>> shared between workstations and "environment" is different
>>> dependent on which computer user is logged in.
>
>  Instead of SQL, just start
> from systemRoot() for shared preferences.
>

System = one computer.  The op wants to share user configurations 
between multiple computers.  Using systemRoot won't help because it's 
limited to a single system.

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#2098

In article <k3dtpq$lmn$1@dont-email.me>, markspace <-@.> wrote:

> On 9/19/2012 5:59 PM, John B. Matthews wrote:
> > In article <k3dgu8$k1h$1@dont-email.me>, markspace <-@.> wrote:
> >
> >> On 9/19/2012 1:51 PM, Marcin wrote:
> >>> if one user can use many computers the data is not shared between 
> >>> workstations and "environment" is different dependent on which 
> >>> computer user is logged in.
> >
> > Instead of SQL, just start from systemRoot() for shared 
> > preferences.
> >
> 
> System = one computer.  The op wants to share user configurations 
> between multiple computers.  Using systemRoot won't help because 
> it's limited to a single system.

D'oh, I misunderstood the question; thanks for clarifying. I wonder if a 
javax.jnlp.PersistenceService might be useful in this context.

<http://pscode.org/jws/api.html#ps>
<http://docs.oracle.com/javase/7/docs/jre/api/javaws/jnlp/javax/jnlp/Pers
istenceService.html>
<http://docs.oracle.com/javase/7/docs/technotes/guides/javaws/developersg
uide/examples.html>

-- 
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>

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#2099

On Wed, 19 Sep 2012 22:51:03 +0200, Marcin <nomail@nospam.com> wrote,
quoted or indirectly quoted someone who said :

> Do you know 
>any implementation of abstract class java.util.prefs.Preferences  that 
>uses SQL to store the configuration data?

On windows, it uses the registry. on Linux it has a little database.

see http://mindprod.com/jgloss/preferences.html
-- 
Roedy Green Canadian Mind Products http://mindprod.com
The iPhone 5 is a low end Rolex. 

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#2101

In article <ldto581bsn26ok3c4vbg5eghf4q6p9o78l@4ax.com>,
 Roedy Green <see_website@mindprod.com.invalid> wrote:

> On Wed, 19 Sep 2012 22:51:03 +0200, Marcin <nomail@nospam.com> wrote,
> quoted or indirectly quoted someone who said :
> 
> > Do you know any implementation of abstract class 
> > java.util.prefs.Preferences  that uses SQL to store the 
> > configuration data?
> 
> On windows, it uses the registry. on Linux it has a little database.
> 
> see http://mindprod.com/jgloss/preferences.html

Given a declaration such as this:

Preferences p = Preferences
    .userRoot().node("org").node("gcs").node("RobotChase");

Mac OS X uses a single XML file for the leaf node:

~/Library/Preferences/org.gcs.robotchase.plist

<http://www.apple.com/DTDs/PropertyList-1.0.dtd>

In contrast, linux uses a directory sub-tree that reflects the node 
structure:

~/.java.userPrefs/org/gcs/RobotChase/prefs.xml

<http://java.sun/dtd/preferences.dtd>

Given the disparate implementations, it's a pretty good abstraction.

-- 
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>

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#2100

On 9/19/12 1:51 PM, Marcin wrote:
> Hello
>
> I have a Java program that uses java.util.prefs.Preferences to store
> configuration data. Everything is OK if one user works on one computer
> but if one user can use many computers the data is not shared between
> workstations and "environment" is different dependent on which computer
> user is logged in. I think I can store the same data in database because
> application uses connection to database for other purposes. Do you know
> any implementation of abstract class java.util.prefs.Preferences  that
> uses SQL to store the configuration data? I cannot google anything
> interesting...
>
> Regards,
> Mar

If you need to store preferences across computers, 
java.util.prefs.Preferences is not the class to do it with. 
java.util.prefs.Preferences was basically meant to be a Java interface 
into the Windows Registry (with a more system-independent back-end). 
You will want to create your own way of persisting user preferences 
which involves storing them on some server somewhere.  You could put it 
into the same database as your application's domain database, though it 
isn't a good excuse that "I'm already connecting to it."

It may be a better implementation to have a separate Preferences 
database, or web-service, or whatever makes sense in your 
environment(s).  Personally, I like the "web-service" approach, but that 
is 80% of what I do on a daily basis, so my preference (no pun intended) 
is biased.

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