How should I find my Screen Saver's preferences?

Question

I'm writing a screen saver that basically draws stuff the user types into a box. I have not completed it yet, because I have not been able to locate where the screen saver preferences are located. Here's the code that takes care of the preferences:
//PrefControl.m
//I wrote this on my brother's school computer. Go !:
#import "PrefControl.h"
//define what you have - not defined in header file because there is no need to access the predefined text in any other file:
#define DISPLAYED_TEXT @"com.nodomain.Saver.DISPLAYED"
@implementation PrefControl
@synthesize displayed;
-(id) init{
self = [super init];
if(self){
//read user defaults
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
displayed = [defaults stringForKey: DISPLAYED_TEXT];
return self;
-(void) writePrefs{
//write preferences the way the UserDefaults guide says to:
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
NSMutableDictionary* defs = [NSMutableDictionary dictionaryWithCapacity:1];
[defs setObject:displayed forKey:DISPLAYED_TEXT];
[defaults registerDefaults:defs];
-(void) dealloc{
[self writePrefs];
[super dealloc];
+(void) initialize{
//set up user defaults for the first time:
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
NSMutableDictionary* defs = [NSMutableDictionary dictionaryWithCapacity:1];
[defs setObject:@"Hello, World!" forKey:DISPLAYED_TEXT];
[defaults registerDefaults:defs];
+(PrefControl*) prefs{
return [[[PrefControl alloc]init]autorelease];
@end
and its header:
//PrefControl.h
//I wrote this.
#import <cocoa/cocoa.h>
@interface PrefControl:NSObject{
NSString* displayed;//the text my Screen Saver displays.
@property(readonly, nonatomic) NSString* displayed;
-(id) init;//sets up all the properties. done over time.
-(void) writePrefs;//writes the defaults.
-(void) dealloc;
+(void) initialize;//sets up the defaults.
+(PrefControl*) prefs;//makes and autoreleases a new PrefControl.
@end
Now on to my question: Where can I find my preferences file? Is it the System Preferences preferences PLIST or is it my own Screen Saver's PLIST? How can I change the file so I can test if it saves properly? I am going to edit it with the PLIST editor that came with XCode.
I prefer to do the behind-the-scenes work before working on the major GUI if I can.

Answer 1

I just did a little test and changed something in my Screen Saver settings and looked to see what changed (just had a Finder window open in my ~/Library/Preferences and had the "Date Modified" column selected so that the most recent change would appear at the top) and noticed that the file called com.apple.screensaver.xxxx.plist file changed (the xxxx is a hex number that is part of your UUID, or perhaps the whole UUID, as have seen it both ways). This screensaver preferences file is located in ~/Library/Preferences/ByHost which makes sense, as every user would need their own set of screen saver preferences on each host.
Looking at this file in TextWrangler it looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>askForPassword</key>
<integer>0</integer>
<key>idleTime</key>
<integer>300</integer>
<key>lastNonRandomModuleName</key>
<string>Flurry</string>
<key>moduleName</key>
<string>Flurry</string>
<key>modulePath</key>
<string>/System/Library/Screen Savers/Flurry.saver</string>
<key>tokenRemovalAction</key>
<integer>0</integer>
</dict>
</plist>
Hope that helps.
One thing I did have a question about is how to find the UUID. On a Mac Pro system the command:
system_profiler | grep -i uuid
returned the expected number that was part of the com.apple.screensaver.xxxx.plist file, but this did not work on a MacBook Pro. No luck trying to find out why so far. Anyone have any ideas? There is also a UUID associated with a disk volume, that appears to have nothing to do with the UUID associated with the system. So the UUID I'm talking about here is for the system, not a disk.
-Bob