Setting flags for elements in NSMutableArray - iphone

Question

I have an NSMutableArray of elements and I want to be able to conditionally set custom flags for some of the elements. For example an error count for certain elements if they return an error. If the count is more than 3, I would like to delete this element from an array.
What would be the best way to implement such behaviour?

Answer 1

A few options:
Have a separate array holding your counter for each object. When deleting one from your original array, remember to delete it's corresponding counter object.
Create a small class that contains an int value and whatever other object you are storing in the array, and populate your NSMutableArray with that object. You will then have your object and the error counter on the same place
Edit: The second option is the most scalable one, if you ever want to add more flags or whatever to it.

Answer 2

You would be better off creating a mutable array filled with mutable dictionaries. This would allow you have two keys corresponding to each index in the array:
NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithObjectsAndKeys:
#"some text, or what ever you want to store",#"body",
[NSNumber numberWithUnsignedInteger:0],#"errorCount",
nil];
[myMutableArray addObject:mutableDictionary];
And then here is a basic example of how to increment the error count for a specific item in the array:
- (void)errorInArray:(NSUInteger)idx
{
if ([[[myMutableArray objectAtIndex:idx] objectForKey:#"errorCount"] unsignedIntegerValue] == 2) {
[myMutableArray removeObjectAtIndex:idx];
}else{
NSUInteger temp = [[[myMutableArray objectAtIndex:idx] objectForKey:#"errorCount"] unsignedIntegerValue];
temp ++;
[[myMutableArray objectAtIndex:idx] setObject:[NSNumber numberWithUnsignedInteger:temp] forKey:#"errorCount"];
}
}

Answer 3

As alluded above, no need for custom object creation necessarily:
Creating a mutable array, creating a dictionary with objects/keys and adding said dictionary to the array:
NSMutableArray *myArray = [[NSMutableArray alloc] init] autorelease];
NSMutableDictionary *myDictionary = [NSMutableDictionary dictionaryWithObjectsAndKeys:
#"John Doe", #"elementName",
[NSNumber numberWithInt:0], #"errorCount",
nil];
[myArray addObject:myDictionary];