EONullValue
- Inherits from:
- (com.apple.client.eocontrol) Object
(com.apple.yellow.eocontrol) NSObject
- Implements:
- (com.apple.client.eocontrol only) NSCoding
- (com.apple.client.eocontrol only) EOSortOrdering.Comparison
- (com.apple.client.eocontrol only) Cloneable
- Package:
- com.apple.client.eocontrol
- com.apple.yellow.eocontrol
Class Description
The EONullValue class defines a unique object used to represent null values in collection objects (which don't allow null values). For example, NSDictionaries fetched by an EOAdaptorChannel contain an EONullValue instance for such values. EONullValue is automatically translated to null in enterprise objects, however, so most applications should rarely need to account for this class.
EONullValue has exactly one instance, returned by the nullValue static method. You can safely cache this instance and use the == operator to test for the presence of a null value:
EONullValue myNull = EONullValue.nullValue(); /* ... */ if (value == myNull) { /* ... */ }
Interfaces Implemented
NSCoding (com.apple.client.eocontrol only)
classForCoder
encodeWithCoder
EOSortOrderingComparison
- compareAscending
- compareCaseInsensitiveAscending
- compareCaseInsensitiveDescending
- compareDescending
Cloneable (com.apple.client.eocontrol only)
Constructors
EONullValue
public
EONullValue
()
Static Methods
nullValue
public static EONullValue
nullValue
()