119 lines
4.4 KiB
Objective-C
119 lines
4.4 KiB
Objective-C
#import "YapDatabase.h"
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#import "YapDatabaseTransaction.h"
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/**
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* A common use case for metadata is to store timestamps.
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*
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* These categories provide a a number of enhancements including:
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*
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* - methods that strongly type the metadata as a date, making compiler type-checks possible
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* - methods for enumerating and cleaning the database.
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*
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* Note: See YapAbstractDatabase.h for a faster serializer/deserializer when using timestamps.
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**/
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@interface YapDatabaseReadTransaction (Timestamp)
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/**
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* This method invokes metadataForKey: and checks the result.
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* If the resulting metadata is of class NSDate, it is returned.
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* Otherwise it returns nil.
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**/
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- (NSDate *)timestampForKey:(NSString *)key;
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/**
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* Returns the list of keys, ordered by metadata timestamp.
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*
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* What do I pass for the 'ordered' parameter? Use:
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* - To enumerate from oldest to newest timestamp (1990,2004,2012): NSOrderedAscending
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* - To enumerate from newest to oldest timestamp (2012,2004,1990): NSOrderedDescending
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*
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* Keys without an associated metadata timestamp are not included in the list.
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*
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* If you don't pass a proper value for the ordered parameter (either NSOrderedAscending or NSOrderedDescending),
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* then the default value of NSOrderedAscending is used.
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**/
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- (NSArray *)allKeysOrdered:(NSComparisonResult)NSOrderedAscendingOrDescending;
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/**
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* Allows you to enumerate the keys based on their metadata timestamp.
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*
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* What do I pass for the 'ordered' parameter? Use:
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* - To enumerate from oldest to newest timestamp (1990,2004,2012): NSOrderedAscending
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* - To enumerate from newest to oldest timestamp (2012,2004,1990): NSOrderedDescending
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*
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* Keys without a metadata timestamp are not included in the enumeration.
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*
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* If you don't pass a proper value for the ordered parameter (either NSOrderedAscending or NSOrderedDescending),
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* then the default value of NSOrderedAscending is used.
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**/
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- (void)enumerateKeysAndMetadataOrdered:(NSComparisonResult)NSOrderedAscendingOrDescending
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usingBlock:
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(void (^)(NSUInteger idx, NSString *key, NSDate *timestamp, BOOL *stop))block;
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/**
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* Allows you to enumerate the objects based on their metadata timestamp.
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*
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* What do I pass for the 'ordered' parameter? Use:
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* - To enumerate from oldest to newest timestamp (1990,2004,2012): NSOrderedAscending
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* - To enumerate from newest to oldest timestamp (2012,2004,1990): NSOrderedDescending
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*
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* Objects without a metadata timestamp are not included in the enumeration.
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*
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* If you don't pass a proper value for the ordered parameter (either NSOrderedAscending or NSOrderedDescending),
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* then the default value of NSOrderedAscending is used.
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**/
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- (void)enumerateKeysAndObjectsOrdered:(NSComparisonResult)NSOrderedAscendingOrDescending
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usingBlock:
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(void (^)(NSUInteger idx, NSString *key, id object, NSDate *timestamp, BOOL *stop))block;
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@end
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@interface YapDatabaseReadWriteTransaction (Timestamp)
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/**
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* This methods simply invokes setObject:forKey:withMetadata:, but provides stronger type safety for the compiler.
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**/
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- (void)setObject:(id)object forKey:(NSString *)key withTimestamp:(NSDate *)timestamp;
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/**
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* This methods simply invokes setMetadata:forKey:, but provides stronger type safety for the compiler.
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**/
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- (void)setTimestamp:(NSDate *)timestamp forKey:(NSString *)key;
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/**
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* Removes any objects that have a metadata timestamp,
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* and whose timestamp is earlier/later than the given date.
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*
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* @return An array of keys that were removed.
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**/
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- (NSArray *)removeObjectsEarlierThan:(NSDate *)date;
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- (NSArray *)removeObjectsLaterThan:(NSDate *)date;
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/**
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* Removes any objects that have a metadata timestamp,
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* and whose timestamp is earlier/later or equal to the given data.
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*
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* @return An array of keys that were removed.
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**/
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- (NSArray *)removeObjectsEarlierThanOrEqualTo:(NSDate *)date;
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- (NSArray *)removeObjectsLaterThanOrEqualTo:(NSDate *)date;
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/**
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* Removes any objects that lie within the given time range (inclusive).
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*
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* That is, if an object has a metadata timestamp, then the object is removed if:
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* startDate >= timestamp <= endDate
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*
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* You may optionally pass nil for one of the dates.
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* For example, if you passed nil for the endDate,
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* then all objects with timestamp later than or equal to the given startDate would be removed.
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*
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* @return An array of keys that were removed.
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**/
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- (NSArray *)removeObjectsFrom:(NSDate *)startDate to:(NSDate *)endDate;
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@end
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