ObjFW  OFNull.m at [3e3f49406a]

File src/OFNull.m artifact 6eac9873fd part of check-in 3e3f49406a

/*
 * Copyright (c) 2008, 2009, 2010, 2011
 *   Jonathan Schleifer <js@webkeks.org>
 *
 * All rights reserved.
 *
 * This file is part of ObjFW. It may be distributed under the terms of the
 * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
 * the packaging of this file.
 *
 * Alternatively, it may be distributed under the terms of the GNU General
 * Public License, either version 2 or 3, which can be found in the file
 * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
 * file.
 */

#include "config.h"

#import "OFNull.h"
#import "OFString.h"
#import "OFXMLElement.h"
#import "OFAutoreleasePool.h"

#import "OFInvalidArgumentException.h"
#import "OFNotImplementedException.h"

static OFNull *null = nil;

@implementation OFNull
+ null
{
	if (null != nil)
		return null;

	null = [[self alloc] init];

	return null;
}

- initWithSerialization: (OFXMLElement*)element
{
	OFAutoreleasePool *pool;

	[self release];

	pool = [[OFAutoreleasePool alloc] init];

	if (![[element name] isEqual: [self className]] ||
	    ![[element namespace] isEqual: OF_SERIALIZATION_NS])
		@throw [OFInvalidArgumentException exceptionWithClass: isa
							     selector: _cmd];

	[pool release];

	return [OFNull null];
}

- (OFString*)description
{
	return @"<null>";
}

- copy
{
	return self;
}

- (OFXMLElement*)XMLElementBySerializing
{
	OFAutoreleasePool *pool = [[OFAutoreleasePool alloc] init];
	OFXMLElement *element;

	element = [OFXMLElement elementWithName: [self className]
				      namespace: OF_SERIALIZATION_NS];

	[element retain];
	[pool release];
	[element autorelease];

	return element;
}

- autorelease
{
	return self;
}

- retain
{
	return self;
}

- (void)release
{
}

- (unsigned int)retainCount
{
	return OF_RETAIN_COUNT_MAX;
}

- (void)dealloc
{
	@throw [OFNotImplementedException exceptionWithClass: isa
						    selector: _cmd];
	[super dealloc];	/* Get rid of a stupid warning */
}
@end