Retired Document
Important: This sample code may not represent best practices for current development. The project may use deprecated symbols and illustrate technologies and techniques that are no longer recommended.
LSMClassifier.m
/* |
File: LSMClassifier.m |
Abstract: LSMClassifier encapsulates common Latent Semantic Mapping (LSM) |
framework functionalities. By studying this class, you will see |
how to use LSM framework in common text classification tasks. |
Version: 1.0 |
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*/ |
#import "LSMClassifier.h" |
#import "LSMClassifierResultPrivate.h" |
NSString* gIdToNameMap = @"IdToNameMap"; |
NSString* gNameToIdMap = @"NameToIdMap"; |
//private methods of LSMClassifier |
@interface LSMClassifier(Private) |
// |
// Update catIdToNameMap and catNameToIdMap to keep them in sync. |
// |
- (void)mapCategoryId:(LSMCategory)index toName:(NSString*)name; |
@end |
@implementation LSMClassifier |
- (id)init |
{ |
self = [super init]; |
if (self) { |
//create the LSM map with default allocator and option |
map = LSMMapCreate(kCFAllocatorDefault, 0); |
//set it to training mode, since the map is brandnew. |
currentMode = kLSMCTraining; |
catIdToNameMap = [NSMutableDictionary new]; |
catNameToIdMap = [NSMutableDictionary new]; |
} |
return self; |
} |
- (void)dealloc |
{ |
//dispose everything |
if (catIdToNameMap) [catIdToNameMap release]; |
if (catNameToIdMap) [catNameToIdMap release]; |
if (map) CFRelease(map); |
[super dealloc]; |
} |
- (void)reset |
{ |
[catIdToNameMap release]; |
[catNameToIdMap release]; |
CFRelease(map); |
//create the LSM map with default allocator and option |
map = LSMMapCreate(kCFAllocatorDefault, 0); |
//set it to training mode, since the map is brandnew. |
currentMode = kLSMCTraining; |
catIdToNameMap = [NSMutableDictionary new]; |
catNameToIdMap = [NSMutableDictionary new]; |
} |
- (OSStatus)setModeTo:(SInt32)mode |
{ |
if (currentMode != mode) |
{ |
switch(mode) |
{ |
case kLSMCTraining: |
//set the map to training mode. |
if (LSMMapStartTraining(map) != noErr) |
return kLSMSetModeFailed; |
else |
return noErr; |
case kLSMCEvaluation: |
//compile the map and start evaluation mode |
if (LSMMapCompile(map) != noErr) |
return kLSMSetModeFailed; |
else |
return noErr; |
default: |
return kLSMCNotValidMode; |
} |
} |
return noErr; |
} |
- (OSStatus)addCategory:(NSString*)name |
{ |
NSNumber* mapId = [catNameToIdMap objectForKey:name]; |
if (mapId) |
return kLSMCDuplicatedCategory; |
[self setModeTo:kLSMCTraining]; |
LSMCategory newCategory = LSMMapAddCategory(map); |
[self mapCategoryId:newCategory toName:name]; |
return noErr; |
} |
- (OSStatus)addTrainingText:(NSString*)text toCategory:(NSString*)name with:(UInt32)option |
{ |
NSNumber* mapId = [catNameToIdMap objectForKey:name]; |
if (!mapId) |
return kLSMCNoSuchCategory; |
//convert input text into LSMText text. |
LSMTextRef lsmText = LSMTextCreate(NULL, map); |
if (LSMTextAddWords(lsmText, (CFStringRef)text, CFLocaleGetSystem(), option) != noErr) |
{ |
CFRelease(lsmText); |
return kLSMCErr; |
} |
//Store current mode so that we can restore the mode if we fail. |
unsigned preMode = currentMode; |
[self setModeTo:kLSMCTraining]; |
LSMCategory category = [mapId unsignedIntValue]; |
OSStatus result = LSMMapAddText(map, lsmText, category); |
CFRelease(lsmText); |
if (result != noErr) |
{ |
//something bad happened. |
//let's recover to original mode and return error. |
if (preMode != currentMode) |
[self setModeTo:preMode]; |
return kLSMCErr; |
} |
else |
return noErr; |
} |
- (LSMClassifierResult*)createResultFor:(NSString*)text upTo:(SInt32)numOfResults with:(UInt32)textOption |
{ |
//convert input text into LSMText text. |
LSMTextRef lsmText = LSMTextCreate(NULL, map); |
if (LSMTextAddWords(lsmText, (CFStringRef)text, CFLocaleGetSystem(), textOption) != noErr) |
{ |
CFRelease(lsmText); |
return nil; |
} |
//switch to evaluation mode |
[self setModeTo:kLSMCEvaluation]; |
LSMResultRef result = LSMResultCreate(NULL, map, lsmText, numOfResults, 0); |
CFRelease(lsmText); |
if (!result) return nil; |
return [[LSMClassifierResult alloc] initWithLSMResult:result withIdToNameMap:catIdToNameMap]; |
} |
- (unsigned)numberOfCategories |
{ |
return [catNameToIdMap count]; |
} |
- (NSEnumerator*)categoryEnumerator |
{ |
return [catNameToIdMap keyEnumerator]; |
} |
- (OSStatus)writeToFile:(NSString*) path |
{ |
//put catNameToIdMap into the map's property list so that |
//we can store them to a file all together. |
//Note, if you plan to store NSDictionary object in the property list, the key |
//has to be NSString. |
NSMutableDictionary* dict = [NSMutableDictionary new]; |
[dict setObject:catNameToIdMap forKey:gNameToIdMap]; |
LSMMapSetProperties(map, (CFDictionaryRef)dict); |
[dict release]; |
NSURL* url = [[NSURL alloc] initFileURLWithPath:path]; |
OSStatus status = LSMMapWriteToURL(map, (CFURLRef)url, 0); |
[url release]; |
return (status == noErr) ? noErr : kLSMCWriteError; |
} |
- (OSStatus)readFromFile:(NSString*)path with:(unsigned)mode |
{ |
CFRelease(map); |
[catIdToNameMap release]; |
[catNameToIdMap release]; |
BOOL ok = YES; |
NSURL* url = [[NSURL alloc] initFileURLWithPath:path]; |
map = LSMMapCreateFromURL(NULL, (CFURLRef)url, kLSMMapLoadMutable); |
[url release]; |
if (!map) |
ok = NO; |
else |
{ |
NSDictionary* idNameMaps = (NSDictionary*)LSMMapGetProperties(map); |
if (idNameMaps) |
{ |
NSDictionary* dict = [idNameMaps objectForKey:gNameToIdMap]; |
if (dict) |
{ |
catNameToIdMap = [[NSMutableDictionary alloc] initWithDictionary:dict]; |
catIdToNameMap = [NSMutableDictionary new]; |
NSEnumerator* keys = [catNameToIdMap keyEnumerator]; |
NSString* key; |
while (key = [keys nextObject]) |
[catIdToNameMap setObject:key forKey:[catNameToIdMap objectForKey:key]]; |
} |
else |
ok = NO; |
} |
else |
ok = NO; |
} |
if (ok) |
return [self setModeTo:mode]; |
else |
{ |
//oops, something wrong. Reset the classifier and bail. |
map = LSMMapCreate(NULL, 0); |
catIdToNameMap = [NSMutableDictionary new]; |
catNameToIdMap = [NSMutableDictionary new]; |
[self setModeTo:kLSMCTraining]; |
return kLSMCErr; |
} |
} |
///// private methods ///// |
- (void)mapCategoryId:(LSMCategory)index toName:(NSString*)name |
{ |
NSNumber* idNumber = [[NSNumber alloc] initWithUnsignedInt:index]; |
[catIdToNameMap setObject:name forKey:idNumber]; |
[catNameToIdMap setObject:idNumber forKey:name]; |
[idNumber release]; |
} |
@end |
Copyright © 2007 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2007-05-09