Dan Wood: The Eponymous Weblog (Archives)

Dan Wood Dan Wood is co-owner of Karelia Software, creating programs for the Macintosh computer. He is the father of two kids, lives in the Bay Area of California USA, and prefers bicycles to cars. This site is his older weblog, which mostly covers geeky topics like Macs and Mac Programming. Go visit the current blog here.

Useful Tidbits and Egotistical Musings from Dan Wood

Categories: Business · Mac OS X · Cocoa Programming · General · All Categories

Thu, 01 May 2008

Self-Registering Transformers

Here is a snippet of code you can put into any subclass of NSValueTransformer that will cause it to automatically register itself when the class is loaded. This is useful for almost all value transformers, except perhaps those that you need to be given a parameter in the initialization process, such as these cool transformer classes.

This code will just cause the transformer to be registered with the name of the class itself. So if you class was, for instance, CondenseTransformer then you would specify "CondenseTransformer" in your nib file.

+ (void)load
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  NSValueTransformer *theTransformer = [[[self alloc] init] autorelease];
  [NSValueTransformer setValueTransformer:theTransformer
         forName:NSStringFromClass([self class])];
  [pool release];