DDXMLParser.m

//
//  DDXMLParser.m
//

#import "DDXMLParser.h"


@implementation DDXMLParser
@synthesize arrayOfDictionaries, delegate;

#pragma mark -
#pragma mark Initialisation

- (id)initWithData:(NSData *)data interestingKeys:(NSSet *)interestingKeys_
	   itemElement:(NSString *)itemElement_ delegate:(id <DDXMLParserDelegate>) delegate_ {
	if((self = [super init])) {
		self.delegate = delegate_;
		//Initialising vars for use across class
		interestingKeys = interestingKeys_;
		itemElement = itemElement_;
		NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];
		parser.delegate = self;
		[parser parse];
		[parser release];
	}	
	return self;
}

#pragma mark -
#pragma mark NSXMLParser delegate methods

- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError {
	NSLog(@"error: %@", [parseError localizedDescription]);
}

- (void)parser:(NSXMLParser *)parser validationErrorOccurred:(NSError *)validError {
	NSLog(@"error: %@", [validError localizedDescription]);
}	

- (void) parserDidStartDocument:(NSXMLParser *)parser {
	self.arrayOfDictionaries = [[NSMutableArray alloc] init];
}

- (void)parser: (NSXMLParser *)parser didStartElement: (NSString *) elementName 
		namespaceURI: (NSString *) namespaceURI
		qualifiedName: (NSString *) qualifiedName
		attributes: (NSDictionary *) attributeDictionary {
	//Create a dictionary to store key-object pairs for items in itemElement
	if([elementName isEqualToString:itemElement]) {
		tempDictionary = [[NSMutableDictionary alloc] init];
	}
	//If the current item is one specified in interestingKeys, 
	//create a temp string to store it and remember which element it is
	if ([interestingKeys containsObject:elementName]) {
		//We prevent duplicate entries for elements of the same name that are 
		//more deeply nested in the XML document - assumes we always want
		//the first element encountered of name elementName!
		if([tempDictionary objectForKey:elementName] == nil) {
			keyInProgress = [elementName copy];
			tempString = [[NSMutableString alloc] init];
		}
	}
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName
		namespaceURI:(NSString *)namespaceURI
		qualifiedName:(NSString *)qName {
	//If we have come to the end of itemElement, we're done for that item
	//so add it to the array and release the temp dictionary
	if([elementName isEqualToString:itemElement]) {
		[self.arrayOfDictionaries addObject:tempDictionary];
		[tempDictionary release];
		tempDictionary = nil;
	} else if ([elementName isEqualToString:keyInProgress]) {
		//Item is one of our interesting keys so add its contents to the dictionary
		[tempDictionary setObject:tempString forKey:elementName];
		//Release all those vars associated with this element since we're done with it
		[keyInProgress release];
		keyInProgress = nil;
		[tempString release];
		tempString = nil;
    }
}

- (void) parser: (NSXMLParser *)parser foundCharacters:(NSString *)string {
	//Append chars to the tempString if we're at an element in interestingKeys
	if(tempString != nil) {
		[tempString appendString:string];
	}
}

- (void) parserDidEndDocument:(NSXMLParser *)parser {
	NSLog(@"parser did end doc called");
	[interestingKeys release];
	interestingKeys = nil;
	[itemElement release];
	itemElement = nil;
	if(self.delegate == nil) {
		NSLog(@"it's nil!");
	}
	[self.delegate parserDidFinishParsingData:self.arrayOfDictionaries];
	
}

- (void)dealloc {
	self.arrayOfDictionaries = nil;
	[super dealloc];
}

@end