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Re: observing dealloc
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Re: observing dealloc


  • Subject: Re: observing dealloc
  • From: Ken Tozier <email@hidden>
  • Date: Tue, 29 May 2007 01:22:48 -0400


On May 29, 2007, at 12:28 AM, Chris Suter wrote:



No.

As others have suggested, why don't you just do something like the following?

+ GlobalVarType *)globalVar
{
  static GlobalVarType *globalVar;
  if (!globalVar)
    globleVar = [[[GlobalVarType alloc] init];
  return globalVar;
}

This obviously isn't thread-safe; you'd have to add any thread safety you might want.

Trying to generalise this would be just making things more complicated for no real gain.

The main reason is that with a generalized mechanism, there's no possibility for static variable name collisions. Many different classes could all have a "gFoo" global without having to dream up a different name for each class. Secondly, with a standard accessor like "globalForKey", there's no need to create individual accessors like you did or clutter up code with all those unique variable names. Just define a set of keys that can be reused in many classes and fetch corresponding globals with these keys.


For example:

NSColor *currentColor = (selected) ? [self globalForKey: @"backgroundColor"] : [self globalForKey: @"foregroundColor"] ;

As opposed to:

NSColor *currentColor = (selected) ? gMyClassBackgroundColor : gMyClassForegroundColor ;


Third, it's cleaner to implement.

Compare this:

int						gMyClassIntGlobal			= 0;
float						gMyClassFloatGlobal			= 0;
NSString				*gMyClassStringGlobal		= nil;
NSMutableDictionary		*gMyClassDictGlobal			= nil;
BOOL					gMyClassGlobalsInitialized	= NO;

+ (void) initialize
{
	if (! gMyClassGlobalsInitialized )
	{
		gMyClassIntGlobal	= 1;
		gMyClassFloatGlobal	= 3.1415926535;
		gMyClassStringGlobal = @"bobo the wonder pig";
		gMyClassDictGlobal	= [[NSMutableDictionary dictionary] retain];
		gMyClassGlobalsInitialized = YES;
	}
}

To this:

+ (void) initialize
{
if (![MyObject globalsInitialized])
{
[MyObject setGlobal: [NSNumber numberWithInt: 1] forKey: @"global_int"];
[MyObject setGlobal: [NSNumber numberWithFloat: 3.1415926535] forKey: @"global_float"];
[MyObject setGlobal: @"bobo the wonder pig" forKey: @"global_string"];
[MyObject setGlobal: [[[NSMutableDictionary dictionary] retain] forKey: @"global_dict"];
}
}



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  • Follow-Ups:
    • Re: observing dealloc
      • From: James Bucanek <email@hidden>
    • Re: observing dealloc
      • From: Ken Tozier <email@hidden>
References: 
 >Re: observing dealloc (From: Erik Buck <email@hidden>)
 >Re: observing dealloc (From: Ken Tozier <email@hidden>)
 >Re: observing dealloc (From: Steve Israelson <email@hidden>)
 >Re: observing dealloc (From: Ken Tozier <email@hidden>)
 >Re: observing dealloc (From: Chris Hanson <email@hidden>)
 >Re: observing dealloc (From: Ken Tozier <email@hidden>)
 >Re: observing dealloc (From: Chris Suter <email@hidden>)

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