写单实例时注意多线程的情况
/**
* Standard entity tables for use with XML parsers.*
* Supported entity tables: ISO 8859-1.
*
* Each table is a dictionary of entity names to NSData objects containing the character.
*/
@interface TTEntityTables : NSObject {
NSDictionary* _iso88591;
}
/**
* Entity table for ISO 8859-1.
*/
@property (nonatomic, readonly) NSDictionary* iso88591;
@end
@interface TTEntityTables (TTSingleton)
// Access the singleton instance: [[TTEntityTables sharedInstance] <methods>]
+ (TTEntityTables*)sharedInstance;
// Release the shared instance.
+ (void)releaseSharedInstance;
@end
@implementation TTEntityTables
@synthesize iso88591 = _iso88591;
///
- (void)dealloc {
TT_RELEASE_SAFELY(_iso88591);
[super dealloc];
}
///
- (NSDictionary*)iso88591 {
if (nil == _iso88591) {
_iso88591 = [[NSDictionary alloc] initWithObjectsAndKeys:
[NSData dataWithBytes:"\"" length:1], @"quot",
[NSData dataWithBytes:"'" length:1], @"apos",
[NSData dataWithBytes:"&" length:1], @"amp",
[NSData dataWithBytes:"<" length:1], @"lt",
[NSData dataWithBytes:">" length:1], @"gt",
[NSData dataWithBytes:" " length:1], @"nbsp",
[@" " dataUsingEncoding:NSUTF8StringEncoding], @"nbsp",
[@"¡" dataUsingEncoding:NSUTF8StringEncoding], @"iexcl",
[@"¢" dataUsingEncoding:NSUTF8StringEncoding], @"cent",
[@"£" dataUsingEncoding:NSUTF8StringEncoding], @"pound",
[@"¤" dataUsingEncoding:NSUTF8StringEncoding], @"curren",
[@"¥" dataUsingEncoding:NSUTF8StringEncoding], @"yen",
[@"¦" dataUsingEncoding:NSUTF8StringEncoding], @"brvbar",
[@"§" dataUsingEncoding:NSUTF8StringEncoding], @"sect",
[@"¨" dataUsingEncoding:NSUTF8StringEncoding], @"uml",
[@"©" dataUsingEncoding:NSUTF8StringEncoding], @"copy",
[@"ª" dataUsingEncoding:NSUTF8StringEncoding], @"ordf",
[@"«" dataUsingEncoding:NSUTF8StringEncoding], @"laquo",
[@"¬" dataUsingEncoding:NSUTF8StringEncoding], @"not",
[@"®" dataUsingEncoding:NSUTF8StringEncoding], @"reg",
[@"¯" dataUsingEncoding:NSUTF8StringEncoding], @"macr",
[@"°" dataUsingEncoding:NSUTF8StringEncoding], @"deg",
[@"±" dataUsingEncoding:NSUTF8StringEncoding], @"plusmn",
[@"²" dataUsingEncoding:NSUTF8StringEncoding], @"sup2",
[@"³" dataUsingEncoding:NSUTF8StringEncoding], @"sup3",
[@"´" dataUsingEncoding:NSUTF8StringEncoding], @"acute",
[@"µ" dataUsingEncoding:NSUTF8StringEncoding], @"micro",
[@"¶" dataUsingEncoding:NSUTF8StringEncoding], @"para",
[@"·" dataUsingEncoding:NSUTF8StringEncoding], @"middot",
[@"¸" dataUsingEncoding:NSUTF8StringEncoding], @"cedil",
[@"¹" dataUsingEncoding:NSUTF8StringEncoding], @"sup1",
[@"º" dataUsingEncoding:NSUTF8StringEncoding], @"ordm",
[@"»" dataUsingEncoding:NSUTF8StringEncoding], @"raquo",
[@"¼" dataUsingEncoding:NSUTF8StringEncoding], @"frac14",
[@"½" dataUsingEncoding:NSUTF8StringEncoding], @"frac12",
[@"¾" dataUsingEncoding:NSUTF8StringEncoding], @"frac34",
[@"¿" dataUsingEncoding:NSUTF8StringEncoding], @"iquest",
[@"×" dataUsingEncoding:NSUTF8StringEncoding], @"times",
[@"÷" dataUsingEncoding:NSUTF8StringEncoding], @"divide",
[@"À" dataUsingEncoding:NSUTF8StringEncoding], @"Agrave",
[@"Á" dataUsingEncoding:NSUTF8StringEncoding], @"Aacute",
[@"Â" dataUsingEncoding:NSUTF8StringEncoding], @"Acirc",
[@"Ã" dataUsingEncoding:NSUTF8StringEncoding], @"Atilde",
[@"Ä" dataUsingEncoding:NSUTF8StringEncoding], @"Auml",
[@"Å" dataUsingEncoding:NSUTF8StringEncoding], @"Aring",
[@"Æ" dataUsingEncoding:NSUTF8StringEncoding], @"AElig",
[@"Ç" dataUsingEncoding:NSUTF8StringEncoding], @"Ccedil",
[@"È" dataUsingEncoding:NSUTF8StringEncoding], @"Egrave",
[@"É" dataUsingEncoding:NSUTF8StringEncoding], @"Eacute",
[@"Ê" dataUsingEncoding:NSUTF8StringEncoding], @"Ecirc",
[@"Ë" dataUsingEncoding:NSUTF8StringEncoding], @"Euml",
[@"Ì" dataUsingEncoding:NSUTF8StringEncoding], @"Igrave",
[@"Í" dataUsingEncoding:NSUTF8StringEncoding], @"Iacute",
[@"Î" dataUsingEncoding:NSUTF8StringEncoding], @"Icirc",
[@"Ï" dataUsingEncoding:NSUTF8StringEncoding], @"Iuml",
[@"Ð" dataUsingEncoding:NSUTF8StringEncoding], @"ETH",
[@"Ñ" dataUsingEncoding:NSUTF8StringEncoding], @"Ntilde",
[@"Ò" dataUsingEncoding:NSUTF8StringEncoding], @"Ograve",
[@"Ó" dataUsingEncoding:NSUTF8StringEncoding], @"Oacute",
[@"Ô" dataUsingEncoding:NSUTF8StringEncoding], @"Ocirc",
[@"Õ" dataUsingEncoding:NSUTF8StringEncoding], @"Otilde",
[@"Ö" dataUsingEncoding:NSUTF8StringEncoding], @"Ouml",
[@"Ø" dataUsingEncoding:NSUTF8StringEncoding], @"Oslash",
[@"Ù" dataUsingEncoding:NSUTF8StringEncoding], @"Ugrave",
[@"Ú" dataUsingEncoding:NSUTF8StringEncoding], @"Uacute",
[@"Û" dataUsingEncoding:NSUTF8StringEncoding], @"Ucirc",
[@"Ü" dataUsingEncoding:NSUTF8StringEncoding], @"Uuml",
[@"Ý" dataUsingEncoding:NSUTF8StringEncoding], @"Yacute",
[@"Þ" dataUsingEncoding:NSUTF8StringEncoding], @"THORN",
[@"ß" dataUsingEncoding:NSUTF8StringEncoding], @"szlig",
[@"à" dataUsingEncoding:NSUTF8StringEncoding], @"agrave",
[@"á" dataUsingEncoding:NSUTF8StringEncoding], @"aacute",
[@"â" dataUsingEncoding:NSUTF8StringEncoding], @"acirc",
[@"ã" dataUsingEncoding:NSUTF8StringEncoding], @"atilde",
[@"ä" dataUsingEncoding:NSUTF8StringEncoding], @"auml",
[@"å" dataUsingEncoding:NSUTF8StringEncoding], @"aring",
[@"æ" dataUsingEncoding:NSUTF8StringEncoding], @"aelig",
[@"ç" dataUsingEncoding:NSUTF8StringEncoding], @"ccedil",
[@"è" dataUsingEncoding:NSUTF8StringEncoding], @"egrave",
[@"é" dataUsingEncoding:NSUTF8StringEncoding], @"eacute",
[@"ê" dataUsingEncoding:NSUTF8StringEncoding], @"ecirc",
[@"ë" dataUsingEncoding:NSUTF8StringEncoding], @"euml",
[@"ì" dataUsingEncoding:NSUTF8StringEncoding], @"igrave",
[@"í" dataUsingEncoding:NSUTF8StringEncoding], @"iacute",
[@"î" dataUsingEncoding:NSUTF8StringEncoding], @"icirc",
[@"ï" dataUsingEncoding:NSUTF8StringEncoding], @"iuml",
[@"ð" dataUsingEncoding:NSUTF8StringEncoding], @"eth",
[@"ñ" dataUsingEncoding:NSUTF8StringEncoding], @"ntilde",
[@"ò" dataUsingEncoding:NSUTF8StringEncoding], @"ograve",
[@"ó" dataUsingEncoding:NSUTF8StringEncoding], @"oacute",
[@"ô" dataUsingEncoding:NSUTF8StringEncoding], @"ocirc",
[@"õ" dataUsingEncoding:NSUTF8StringEncoding], @"otilde",
[@"ö" dataUsingEncoding:NSUTF8StringEncoding], @"ouml",
[@"ø" dataUsingEncoding:NSUTF8StringEncoding], @"oslash",
[@"ù" dataUsingEncoding:NSUTF8StringEncoding], @"ugrave",
[@"ú" dataUsingEncoding:NSUTF8StringEncoding], @"uacute",
[@"û" dataUsingEncoding:NSUTF8StringEncoding], @"ucirc",
[@"ü" dataUsingEncoding:NSUTF8StringEncoding], @"uuml",
[@"ý" dataUsingEncoding:NSUTF8StringEncoding], @"yacute",
[@"þ" dataUsingEncoding:NSUTF8StringEncoding], @"thorn",
[@"ÿ" dataUsingEncoding:NSUTF8StringEncoding], @"yuml",
nil];
}
return _iso88591;
}
@end
@implementation TTEntityTables (TTSingleton)
static TTEntityTables* sharedInstance = nil;
///
+ (id)sharedInstance {
@synchronized(self) {
if (nil == sharedInstance) {
sharedInstance = [[self alloc] init];
}
}
return sharedInstance;
}
///
- (oneway void)superRelease {
[super release];
}
///
+ (void)releaseSharedInstance {
@synchronized(self) {
[sharedInstance superRelease];
sharedInstance = nil;
}
}
///
+ (id)allocWithZone:(NSZone*)zone {
@synchronized(self) {
if (nil == sharedInstance) {
sharedInstance = [super allocWithZone:zone];
}
}
return sharedInstance;
}
///
- (id)copyWithZone:(NSZone *)zone {
return sharedInstance;
}
///
- (id)retain {
return sharedInstance;
}
///
- (unsigned)retainCount {
return NSUIntegerMax;
}
oneway is used with the distributed objects API, which allows use of objective-c objects between different threads or applications. It tells the system that it should not block the calling thread until the method returns. Without it, the caller will block, even though the method's return type is void. Obviously, it is never used with anything other than void, as doing so would mean the method returns something, but the caller doesn't get it
///
- (oneway void)release {
// Do nothing.
}
///
- (id)autorelease {
return sharedInstance;
}
@end
