| Inherits from | |
| Conforms to | |
| Framework | /System/Library/Frameworks/Foundation.framework |
| Availability | Available in Mac OS X v10.2 and later. |
| Companion guide | |
| Declared in | NSKeyedArchiver.h |
| Related sample code |
NSKeyedUnarchiver, a concrete subclass of NSCoder, defines methods for decoding a set of named objects (and scalar values) from a keyed archive. Such archives are produced by instances of the NSKeyedArchiver class.
A keyed archive is encoded as a hierarchy of objects. Each object in the hierarchy serves as a namespace into which other objects are encoded. The objects available for decoding are restricted to those that were encoded within the immediate scope of a particular object. Objects encoded elsewhere in the hierarchy, whether higher than, lower than, or parallel to this particular object, are not accessible. In this way, the keys used by a particular object to encode its instance variables need to be unique only within the scope of that object.
If you invoke one of the decode... methods of this class using a key that does not exist in the archive, a non-positive value is returned. This value varies by decoded type. For example, if a key does not exist in an archive, decodeBoolForKey: returns NO, decodeIntForKey: returns 0, and decodeObjectForKey: returns nil.
NSKeyedUnarchiver supports limited type coercion. A value encoded as any type of integer, whether a standard int or an explicit 32-bit or 64-bit integer, can be decoded using any of the integer decode methods. Likewise, a value encoded as a float or double can be decoded as either a float or a double value. If an encoded value is too large to fit within the coerced type, the decoding method raises an NSRangeException. Further, when trying to coerce a value to an incompatible type, for example decoding an int as a float, the decoding method raises an NSInvalidUnarchiveOperationException.
– containsValueForKey:
– decodeBoolForKey:
– decodeBytesForKey:returnedLength:
– decodeDoubleForKey:
– decodeFloatForKey:
– decodeIntForKey:
– decodeInt32ForKey:
– decodeInt64ForKey:
– decodeObjectForKey:
– finishDecoding
Returns the class from which NSKeyedUnarchiver instantiates an encoded object with a given class name.
+ (Class)classForClassName:(NSString *)codedName
The ostensible name of a class in an archive.
The class from which NSKeyedUnarchiver instantiates an object encoded with the class name codedName. Returns nil if NSKeyedUnarchiver does not have a translation mapping for codedName.
NSKeyedArchiver.hAdds a class translation mapping to NSKeyedUnarchiver whereby objects encoded with a given class name are decoded as instances of a given class instead.
+ (void)setClass:(Class)cls forClassName:(NSString *)codedName
The class with which to replace instances of the class named codedName.
The ostensible name of a class in an archive.
When decoding, the class’s translation mapping is used only if no translation is found first in an instance’s separate translation map.
NSKeyedArchiver.hDecodes and returns the object graph previously encoded by NSKeyedArchiver and stored in a given NSData object.
+ (id)unarchiveObjectWithData:(NSData *)data
An object graph previously encoded by NSKeyedArchiver.
The object graph previously encoded by NSKeyedArchiver and stored in data.
This method raises an NSInvalidArchiveOperationException if data is not a valid archive.
NSKeyedArchiver.hDecodes and returns the object graph previously encoded by NSKeyedArchiver written to the file at a given path.
+ (id)unarchiveObjectWithFile:(NSString *)path
A path to a file that contains an object graph previously encoded by NSKeyedArchiver.
The object graph previously encoded by NSKeyedArchiver written to the file path. Returns nil if there is no file at path.
This method raises an NSInvalidArgumentException if the file at path does not contain a valid archive.
NSKeyedArchiver.hReturns the class from which the receiver instantiates an encoded object with a given class name.
- (Class)classForClassName:(NSString *)codedName
The name of a class.
The class from which the receiver instantiates an encoded object with the class name codedName. Returns nil if the receiver does not have a translation mapping for codedName.
The class’s separate translation map is not searched.
NSKeyedArchiver.hReturns a Boolean value that indicates whether the archive contains a value for a given key within the current decoding scope.
- (BOOL)containsValueForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
YES if the archive contains a value for key within the current decoding scope, otherwise NO.
NSKeyedArchiver.hDecodes a Boolean value associated with a given key.
- (BOOL)decodeBoolForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
The Boolean value associated with the key key. Returns NO if key does not exist.
– encodeBool:forKey: (NSKeyedArchiver)NSKeyedArchiver.hDecodes a stream of bytes associated with a given key.
- (const uint8_t *)decodeBytesForKey:(NSString *)key returnedLength:(NSUInteger *)lengthp
A key in the archive within the current decoding scope. key must not be nil.
Upon return, contains the number of bytes returned.
The stream of bytes associated with the key key. Returns NULL if key does not exist.
The returned value is a pointer to a temporary buffer owned by the receiver. The buffer goes away with the unarchiver, not the containing autorelease pool. You must copy the bytes into your own buffer if you need the data to persist beyond the life of the receiver.
– encodeBytes:length:forKey: (NSKeyedArchiver)NSKeyedArchiver.hDecodes a double-precision floating-point value associated with a given key.
- (double)decodeDoubleForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
The double-precision floating-point value associated with the key key. Returns 0.0 if key does not exist.
If the archived value was encoded as single-precision, the type is coerced.
– encodeDouble:forKey: (NSKeyedArchiver)– encodeFloat:forKey: (NSKeyedArchiver)NSKeyedArchiver.hDecodes a single-precision floating-point value associated with a given key.
- (float)decodeFloatForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
The single-precision floating-point value associated with the key key. Returns 0.0 if key does not exist.
If the archived value was encoded as double precision, the type is coerced, loosing precision. If the archived value is too large for single precision, the method raises an NSRangeException.
– encodeFloat:forKey: (NSKeyedArchiver)– encodeDouble:forKey: (NSKeyedArchiver)NSKeyedArchiver.hDecodes a 32-bit integer value associated with a given key.
- (int32_t)decodeInt32ForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
The 32-bit integer value associated with the key key. Returns 0 if key does not exist.
If the archived value was encoded with a different size but is still an integer, the type is coerced. If the archived value is too large to fit into a 32-bit integer, the method raises an NSRangeException.
– encodeInt32:forKey: (NSKeyedArchiver)NSKeyedArchiver.hDecodes a 64-bit integer value associated with a given key.
- (int64_t)decodeInt64ForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
The 64-bit integer value associated with the key key. Returns 0 if key does not exist.
If the archived value was encoded with a different size but is still an integer, the type is coerced.
– encodeInt64:forKey: (NSKeyedArchiver)NSKeyedArchiver.hDecodes an integer value associated with a given key.
- (int)decodeIntForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
The integer value associated with the key key. Returns 0 if key does not exist.
If the archived value was encoded with a different size but is still an integer, the type is coerced. If the archived value is too large to fit into the default size for an integer, the method raises an NSRangeException.
– encodeInt:forKey: (NSKeyedArchiver)NSKeyedArchiver.hDecodes and returns an object associated with a given key.
- (id)decodeObjectForKey:(NSString *)key
A key in the archive within the current decoding scope. key must not be nil.
The object associated with the key key. Returns nil if key does not exist, or if the value for key is nil.
– encodeObject:forKey: (NSKeyedArchiver)NSKeyedArchiver.hReturns the receiver’s delegate.
- (id < NSKeyedUnarchiverDelegate >)delegate
The receiver’s delegate.
NSKeyedArchiver.hTells the receiver that you are finished decoding objects.
- (void)finishDecoding
Invoking this method allows the receiver to notify its delegate and to perform any final operations on the archive. Once this method is invoked, the receiver cannot decode any further values.
NSKeyedArchiver.hInitializes the receiver for decoding an archive previously encoded by NSKeyedArchiver.
- (id)initForReadingWithData:(NSData *)data
An archive previously encoded by NSKeyedArchiver.
An NSKeyedUnarchiver object initialized for for decoding data.
When you finish decoding data, you should invoke finishDecoding.
This method raises an NSInvalidArchiveOperationException if data is not a valid archive.
NSKeyedArchiver.hAdds a class translation mapping to the receiver whereby objects encoded with a given class name are decoded as instances of a given class instead.
- (void)setClass:(Class)cls forClassName:(NSString *)codedName
The class with which to replace instances of the class named codedName.
The ostensible name of a class in an archive.
When decoding, the receiver’s translation map overrides any translation that may also be present in the class’s map (see setClass:forClassName:).
NSKeyedArchiver.hSets the receiver’s delegate.
- (void)setDelegate:(id < NSKeyedUnarchiverDelegate >)delegate
The delegate for the receiver.
NSKeyedArchiver.hNames of exceptions that are raised by NSKeyedUnarchiver if there is a problem extracting an archive.
NSString *NSInvalidUnarchiveOperationException;
Last updated: 2009-04-15
Mac OS X Reference Library Data Management: File Management NSKeyedUnarchiver Class Reference