RLMObjectId

@interface RLMObjectId : NSObject

A 12-byte (probably) unique object identifier.

ObjectIds are similar to a GUID or a UUID, and can be used to uniquely identify objects without a centralized ID generator. An ObjectID consists of:

  1. A 4 byte timestamp measuring the creation time of the ObjectId in seconds since the Unix epoch.
  2. A 5 byte random value
  3. A 3 byte counter, initialized to a random value.

ObjectIds are intended to be fast to generate. Sorting by an ObjectId field will typically result in the objects being sorted in creation order.

  • Creates a new randomly-initialized ObjectId.

    Declaration

    Objective-C

    + (nonnull instancetype)objectId;

    Swift

    class func generate() -> Self
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  • Creates a new zero-initialized ObjectId.

    Declaration

    Objective-C

    - (nonnull instancetype)init;

    Swift

    init()
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  • Creates a new ObjectId from the given 24-byte hexadecimal string.

    Returns nil and sets error if the string is not 24 characters long or contains any characters other than 0-9a-fA-F.

    Declaration

    Objective-C

    - (nullable instancetype)initWithString:(nonnull NSString *)string
                                  error:(NSError *_Nullable *_Nullable)error;

    Swift

    init(string: String) throws

    Parameters

    string

    The string to parse.
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  • Creates a new ObjectId using the given date, machine identifier, process identifier.

    Declaration

    Objective-C

    - (nonnull instancetype)initWithTimestamp:(nonnull NSDate *)timestamp
                        machineIdentifier:(int)machineIdentifier
                        processIdentifier:(int)processIdentifier;

    Swift

    init(timestamp: Date, machineIdentifier: Int32, processIdentifier: Int32)

    Parameters

    timestamp

    A timestamp as NSDate.
    machineIdentifier

    The machine identifier.
    processIdentifier

    The process identifier.
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  • Comparision operator to check if the right hand side is greater than the current value.

    Declaration

    Objective-C

    - (BOOL)isGreaterThan:(nullable RLMObjectId *)objectId;

    Swift

    func isGreaterThan(_ objectId: RLMObjectId?) -> Bool
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  • Comparision operator to check if the right hand side is greater than or equal to the current value.

    Declaration

    Objective-C

    - (BOOL)isGreaterThanOrEqualTo:(nullable RLMObjectId *)objectId;

    Swift

    func isGreaterThanOrEqual(to objectId: RLMObjectId?) -> Bool
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  • Comparision operator to check if the right hand side is less than the current value.

    Declaration

    Objective-C

    - (BOOL)isLessThan:(nullable RLMObjectId *)objectId;

    Swift

    func isLessThan(_ objectId: RLMObjectId?) -> Bool
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  • Comparision operator to check if the right hand side is less than or equal to the current value.

    Declaration

    Objective-C

    - (BOOL)isLessThanOrEqualTo:(nullable RLMObjectId *)objectId;

    Swift

    func isLessThanOrEqual(to objectId: RLMObjectId?) -> Bool
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  • Get the ObjectId as a 24-character hexadecimal string.

    Declaration

    Objective-C

    @property (nonatomic, readonly) NSString *_Nonnull stringValue;

    Swift

    var stringValue: String { get }
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  • Get the timestamp for the RLMObjectId

    Declaration

    Objective-C

    @property (nonatomic, readonly) NSDate *_Nonnull timestamp;

    Swift

    var timestamp: Date { get }
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