** NSObject category CocoaDevUsersAdditions:**

** NSObject +CocoaDevUsersAdditions.h**

#import <Foundation/Foundation.h>

@interface NSObject (CocoaDevUsersAdditions)

// NOTE: results array contains instance of NSNull where result of performing selector is nil // a collection here is anything responding to -objectEnumerator

• (void)performSelector:(SEL)aSelector withEachObjectFrom:(id)collection;

• (NSArray *)resultsOfPerformingSelector:(SEL)aSelector withEachObjectFrom:(id)collection;

• (void)log; //A very commonly used method, make it part of your default application project in PB or XC

• (id)arrayByAddingObject:(id)anObject; // a convenience for those of us who like to avoid special cases for collections

@end

NSObject+CocoaDevUsersAdditions.m

#import “NSObject+CocoaDevUsersAdditions.h”

@implementation NSObject (CocoaDevUsersAdditions)

• (void)performSelector:(SEL)aSelector withEachObjectFrom:(id)collection { NSEnumerator *objectEnumerator = [collection objectEnumerator]; id object;

  while(object = [objectEnumerator nextObject]) { [self performSelector:aSelector withObject:object]; } }

• (NSArray *)resultsOfPerformingSelector:(SEL)aSelector withEachObjectFrom:(id)collection { NSEnumerator *objectEnumerator = [collection objectEnumerator]; NSMutableArray *results = [NSMutableArray array]; id object, result;

  while(object = [objectEnumerator nextObject]) { result = [self performSelector:aSelector withObject:object]; if (result == nil) result = [NSNull null]; [results addObject:result]; } return results; }

• (void)log { NSLog(@”%@”,self); }

• (id)arrayByAddingObject:(id)anObject { return [NSArray arrayWithObjects:self, anObject, nil]; // NSArray will still behave normally, too } @end

Category:CocoaDevUsersAdditions