NSArray category

Each method in the NSArray category corresponds to a method in the NSArray class, but provides a secure version of the functionality. For more information about the functionality and usage, see NSArray in developer.apple.com.

Note the following:

•The url parameter in the category methods must be a file URL, and point to a regular file.

•The category methods return an NSError object. The methods set the properties on the object as described in NSError objects that secure Objective-C methods return.

The following table shows each added method and its corresponding method in NSArray.

Table 30.   NSArray category methods

Method in category

Corresponding method in NSArray

 
+ (id)
   arrayWithContentsOfSecureFile:
   (NSString *)path
   error:(
      NSError *__autoreleasing *)error;
 
+ (id)arrayWithContentsOfFile:
   (NSString *)path;
 
+ (id)
   arrayWithContentsOfSecureURL:
   (NSURL *)aURL
   error:(
      NSError *__autoreleasing *)error;
 
+ (id)arrayWithContentsOfURL:
   (NSURL *)aURL;
 
 
- (id)initWithContentsOfSecureFile:
   (NSString *)path
   error:(
      NSError *__autoreleasing *)error;
 
- (id)initWithContentsOfFile:
   (NSString *)path;
 
 
- (id)initWithContentsOfSecureURL:
   (NSURL *)aURL
   error:(
      NSError *__autoreleasing *)error;
 
- (id)initWithContentsOfURL:
   (NSURL *)aURL;
 
 
- (BOOL)writeToSecureFile:
   (NSString *)path 
   atomically:(BOOL)flag
   error:(
      NSError *__autoreleasing *)error;
 
- (BOOL)writeToFile:
   (NSString *)path 
   atomically:(BOOL)flag;
 
 
- (BOOL)writeToSecureURL:
   (NSURL *)aURL 
   atomically:(BOOL)flag
   error:(
      NSError *__autoreleasing *)error;
 
- (BOOL)writeToURL:
   (NSURL *)aURL 
   atomically:(BOOL)flag;
 

Example:

The following example shows how to use NSArray and NSMutableArray category methods to:

1. Create a secure file and write data to it from a NSMutableArray object.
2. Read the contents of the secure file into an NSArray object.

For brevity, the example does not include error handling.

- (void)NSArrayCategoryExample
{
	NSError *error;
 
	// Create an array and populate it.
        NSArray *array = [NSArray arrayWithObjects:@"one fish", @"two fish", @"red fish",
				                    @"blue fish", nil];	
 
	// Write the array to a secure file.
	NSString *secureArrayFileName = @"/tmp/secureArray";
	[array writeToSecureFile:secureArrayFileName atomically:TRUE error:&error];
 
	// Create an array from the contents of the secure file. 
	NSArray *arrayCopy = [[NSArray alloc]
				initWithContentsOfSecureFile:secureArrayFileName error:&error];
 
	// The contents of the objects 'array' and 'arrayCopy' are identical. 
}