//////////////////////////////////////////////////////////////////////////// // // Copyright 2014 Realm Inc. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // //////////////////////////////////////////////////////////////////////////// #import #import @class RLMRealmConfiguration, RLMRealm, RLMObject, RLMSchema, RLMMigration, RLMNotificationToken, RLMThreadSafeReference, RLMAsyncOpenTask; /** A callback block for opening Realms asynchronously. Returns the Realm if the open was successful, or an error otherwise. */ typedef void(^RLMAsyncOpenRealmCallback)(RLMRealm * _Nullable realm, NSError * _Nullable error); NS_ASSUME_NONNULL_BEGIN /** An `RLMRealm` instance (also referred to as "a Realm") represents a Realm database. Realms can either be stored on disk (see `+[RLMRealm realmWithURL:]`) or in memory (see `RLMRealmConfiguration`). `RLMRealm` instances are cached internally, and constructing equivalent `RLMRealm` objects (for example, by using the same path or identifier) multiple times on a single thread within a single iteration of the run loop will normally return the same `RLMRealm` object. If you specifically want to ensure an `RLMRealm` instance is destroyed (for example, if you wish to open a Realm, check some property, and then possibly delete the Realm file and re-open it), place the code which uses the Realm within an `@autoreleasepool {}` and ensure you have no other strong references to it. @warning Non-frozen `RLMRealm` instances are thread-confined and cannot be shared across threads or dispatch queues. Trying to do so will cause an exception to be thrown. You must call this method on each thread you want to interact with the Realm on. For dispatch queues, this means that you must call it in each block which is dispatched, as a queue is not guaranteed to run all of its blocks on the same thread. */ @interface RLMRealm : NSObject #pragma mark - Creating & Initializing a Realm /** Obtains an instance of the default Realm. The default Realm is used by the `RLMObject` class methods which do not take an `RLMRealm` parameter, but is otherwise not special. The default Realm is persisted as *default.realm* under the *Documents* directory of your Application on iOS, in your application's *Application Support* directory on macOS, and in the *Cache* directory on tvOS. The default Realm is created using the default `RLMRealmConfiguration`, which can be changed via `+[RLMRealmConfiguration setDefaultConfiguration:]`. @return The default `RLMRealm` instance for the current thread. */ + (instancetype)defaultRealm; /** Obtains an instance of the default Realm bound to the given queue. Rather than being confined to the thread they are opened on, queue-bound RLMRealms are confined to the given queue. They can be accessed from any thread as long as it is from within a block dispatch to the queue, and notifications will be delivered to the queue instead of a thread's run loop. Realms can only be confined to a serial queue. Queue-confined RLMRealm instances can be obtained when not on that queue, but attempting to do anything with that instance without first dispatching to the queue will throw an incorrect thread exception. The default Realm is created using the default `RLMRealmConfiguration`, which can be changed via `+[RLMRealmConfiguration setDefaultConfiguration:]`. @param queue A serial dispatch queue to confine the Realm to. @return The default `RLMRealm` instance for the given queue. */ + (instancetype)defaultRealmForQueue:(dispatch_queue_t)queue; /** Obtains an `RLMRealm` instance with the given configuration. @param configuration A configuration object to use when creating the Realm. @param error If an error occurs, upon return contains an `NSError` object that describes the problem. If you are not interested in possible errors, pass in `NULL`. @return An `RLMRealm` instance. */ + (nullable instancetype)realmWithConfiguration:(RLMRealmConfiguration *)configuration error:(NSError **)error; /** Obtains an `RLMRealm` instance with the given configuration bound to the given queue. Rather than being confined to the thread they are opened on, queue-bound RLMRealms are confined to the given queue. They can be accessed from any thread as long as it is from within a block dispatch to the queue, and notifications will be delivered to the queue instead of a thread's run loop. Realms can only be confined to a serial queue. Queue-confined RLMRealm instances can be obtained when not on that queue, but attempting to do anything with that instance without first dispatching to the queue will throw an incorrect thread exception. @param configuration A configuration object to use when creating the Realm. @param queue A serial dispatch queue to confine the Realm to. @param error If an error occurs, upon return contains an `NSError` object that describes the problem. If you are not interested in possible errors, pass in `NULL`. @return An `RLMRealm` instance. */ + (nullable instancetype)realmWithConfiguration:(RLMRealmConfiguration *)configuration queue:(nullable dispatch_queue_t)queue error:(NSError **)error; /** Obtains an `RLMRealm` instance persisted at a specified file URL. @param fileURL The local URL of the file the Realm should be saved at. @return An `RLMRealm` instance. */ + (instancetype)realmWithURL:(NSURL *)fileURL; /** Asynchronously open a Realm and deliver it to a block on the given queue. Opening a Realm asynchronously will perform all work needed to get the Realm to a usable state (such as running potentially time-consuming migrations) on a background thread before dispatching to the given queue. In addition, synchronized Realms wait for all remote content available at the time the operation began to be downloaded and available locally. The Realm passed to the callback function is confined to the callback queue as if `-[RLMRealm realmWithConfiguration:queue:error]` was used. @param configuration A configuration object to use when opening the Realm. @param callbackQueue The serial dispatch queue on which the callback should be run. @param callback A callback block. If the Realm was successfully opened, it will be passed in as an argument. Otherwise, an `NSError` describing what went wrong will be passed to the block instead. */ + (RLMAsyncOpenTask *)asyncOpenWithConfiguration:(RLMRealmConfiguration *)configuration callbackQueue:(dispatch_queue_t)callbackQueue callback:(RLMAsyncOpenRealmCallback)callback; /** The `RLMSchema` used by the Realm. */ @property (nonatomic, readonly) RLMSchema *schema; /** Indicates if the Realm is currently engaged in a write transaction. @warning Do not simply check this property and then start a write transaction whenever an object needs to be created, updated, or removed. Doing so might cause a large number of write transactions to be created, degrading performance. Instead, always prefer performing multiple updates during a single transaction. */ @property (nonatomic, readonly) BOOL inWriteTransaction; /** The `RLMRealmConfiguration` object that was used to create this `RLMRealm` instance. */ @property (nonatomic, readonly) RLMRealmConfiguration *configuration; /** Indicates if this Realm contains any objects. */ @property (nonatomic, readonly) BOOL isEmpty; /** Indicates if this Realm is frozen. @see `-[RLMRealm freeze]` */ @property (nonatomic, readonly, getter=isFrozen) BOOL frozen; /** Returns a frozen (immutable) snapshot of this Realm. A frozen Realm is an immutable snapshot view of a particular version of a Realm's data. Unlike normal RLMRealm instances, it does not live-update to reflect writes made to the Realm, and can be accessed from any thread. Writing to a frozen Realm is not allowed, and attempting to begin a write transaction will throw an exception. All objects and collections read from a frozen Realm will also be frozen. */ - (RLMRealm *)freeze NS_RETURNS_RETAINED; /** Returns a live reference of this Realm. All objects and collections read from the returned Realm will no longer be frozen. This method will return `self` if it is not already frozen. */ - (RLMRealm *)thaw; #pragma mark - File Management /** Writes a compacted and optionally encrypted copy of the Realm to the given local URL. The destination file cannot already exist. Note that if this method is called from within a write transaction, the *current* data is written, not the data from the point when the previous write transaction was committed. @param fileURL Local URL to save the Realm to. @param key Optional 64-byte encryption key to encrypt the new file with. @param error If an error occurs, upon return contains an `NSError` object that describes the problem. If you are not interested in possible errors, pass in `NULL`. @return `YES` if the Realm was successfully written to disk, `NO` if an error occurred. */ - (BOOL)writeCopyToURL:(NSURL *)fileURL encryptionKey:(nullable NSData *)key error:(NSError **)error; /** Checks if the Realm file for the given configuration exists locally on disk. For non-synchronized, non-in-memory Realms, this is equivalent to `-[NSFileManager.defaultManager fileExistsAtPath:config.path]`. For synchronized Realms, it takes care of computing the actual path on disk based on the server, virtual path, and user as is done when opening the Realm. @param config A Realm configuration to check the existence of. @return YES if the Realm file for the given configuration exists on disk, NO otherwise. */ + (BOOL)fileExistsForConfiguration:(RLMRealmConfiguration *)config; /** Deletes the local Realm file and associated temporary files for the given configuration. This deletes the ".realm", ".note" and ".management" files which would be created by opening the Realm with the given configuration. It does not delete the ".lock" file (which contains no persisted data and is recreated from scratch every time the Realm file is opened). The Realm must not be currently open on any thread or in another process. If it is, this will return NO and report the error RLMErrorAlreadyOpen. Attempting to open the Realm on another thread while the deletion is happening will block (and then create a new Realm and open that afterwards). If the Realm already does not exist this will return `NO` and report the error NSFileNoSuchFileError; @param config A Realm configuration identifying the Realm to be deleted. @return YES if any files were deleted, NO otherwise. */ + (BOOL)deleteFilesForConfiguration:(RLMRealmConfiguration *)config error:(NSError **)error __attribute__((swift_error(nonnull_error))); #pragma mark - Notifications /** The type of a block to run whenever the data within the Realm is modified. @see `-[RLMRealm addNotificationBlock:]` */ typedef void (^RLMNotificationBlock)(RLMNotification notification, RLMRealm *realm); #pragma mark - Receiving Notification when a Realm Changes /** Adds a notification handler for changes in this Realm, and returns a notification token. Notification handlers are called after each write transaction is committed, either on the current thread or other threads. Handler blocks are called on the same thread that they were added on, and may only be added on threads which are currently within a run loop. Unless you are specifically creating and running a run loop on a background thread, this will normally only be the main thread. The block has the following definition: typedef void(^RLMNotificationBlock)(RLMNotification notification, RLMRealm *realm); It receives the following parameters: - `NSString` \***notification**: The name of the incoming notification. See `RLMRealmNotification` for information on what notifications are sent. - `RLMRealm` \***realm**: The Realm for which this notification occurred. @param block A block which is called to process Realm notifications. @return A token object which must be retained as long as you wish to continue receiving change notifications. */ - (RLMNotificationToken *)addNotificationBlock:(RLMNotificationBlock)block __attribute__((warn_unused_result)); #pragma mark - Writing to a Realm /** Begins a write transaction on the Realm. Only one write transaction can be open at a time for each Realm file. Write transactions cannot be nested, and trying to begin a write transaction on a Realm which is already in a write transaction will throw an exception. Calls to `beginWriteTransaction` from `RLMRealm` instances for the same Realm file in other threads or other processes will block until the current write transaction completes or is cancelled. Before beginning the write transaction, `beginWriteTransaction` updates the `RLMRealm` instance to the latest Realm version, as if `refresh` had been called, and generates notifications if applicable. This has no effect if the Realm was already up to date. It is rarely a good idea to have write transactions span multiple cycles of the run loop, but if you do wish to do so you will need to ensure that the Realm participating in the write transaction is kept alive until the write transaction is committed. */ - (void)beginWriteTransaction; /** Commits all write operations in the current write transaction, and ends the transaction. After saving the changes, all notification blocks registered on this specific `RLMRealm` instance are invoked synchronously. Notification blocks registered on other threads or on collections are invoked asynchronously. If you do not want to receive a specific notification for this write tranaction, see `commitWriteTransactionWithoutNotifying:error:`. This method can fail if there is insufficient disk space available to save the writes made, or due to unexpected i/o errors. This version of the method throws an exception when errors occur. Use the version with a `NSError` out parameter instead if you wish to handle errors. @warning This method may only be called during a write transaction. */ - (void)commitWriteTransaction NS_SWIFT_UNAVAILABLE(""); /** Commits all write operations in the current write transaction, and ends the transaction. After saving the changes, all notification blocks registered on this specific `RLMRealm` instance are invoked synchronously. Notification blocks registered on other threads or on collections are invoked asynchronously. If you do not want to receive a specific notification for this write tranaction, see `commitWriteTransactionWithoutNotifying:error:`. This method can fail if there is insufficient disk space available to save the writes made, or due to unexpected i/o errors. @warning This method may only be called during a write transaction. @param error If an error occurs, upon return contains an `NSError` object that describes the problem. If you are not interested in possible errors, pass in `NULL`. @return Whether the transaction succeeded. */ - (BOOL)commitWriteTransaction:(NSError **)error; /** Commits all write operations in the current write transaction, without notifying specific notification blocks of the changes. After saving the changes, all notification blocks registered on this specific `RLMRealm` instance are invoked synchronously. Notification blocks registered on other threads or on collections are scheduled to be invoked asynchronously. You can skip notifiying specific notification blocks about the changes made in this write transaction by passing in their associated notification tokens. This is primarily useful when the write transaction is saving changes already made in the UI and you do not want to have the notification block attempt to re-apply the same changes. The tokens passed to this method must be for notifications for this specific `RLMRealm` instance. Notifications for different threads cannot be skipped using this method. This method can fail if there is insufficient disk space available to save the writes made, or due to unexpected i/o errors. @warning This method may only be called during a write transaction. @param tokens An array of notification tokens which were returned from adding callbacks which you do not want to be notified for the changes made in this write transaction. @param error If an error occurs, upon return contains an `NSError` object that describes the problem. If you are not interested in possible errors, pass in `NULL`. @return Whether the transaction succeeded. */ - (BOOL)commitWriteTransactionWithoutNotifying:(NSArray *)tokens error:(NSError **)error; /** Reverts all writes made during the current write transaction and ends the transaction. This rolls back all objects in the Realm to the state they were in at the beginning of the write transaction, and then ends the transaction. This restores the data for deleted objects, but does not revive invalidated object instances. Any `RLMObject`s which were added to the Realm will be invalidated rather than becoming unmanaged. Given the following code: ObjectType *oldObject = [[ObjectType objectsWhere:@"..."] firstObject]; ObjectType *newObject = [[ObjectType alloc] init]; [realm beginWriteTransaction]; [realm addObject:newObject]; [realm deleteObject:oldObject]; [realm cancelWriteTransaction]; Both `oldObject` and `newObject` will return `YES` for `isInvalidated`, but re-running the query which provided `oldObject` will once again return the valid object. KVO observers on any objects which were modified during the transaction will be notified about the change back to their initial values, but no other notifcations are produced by a cancelled write transaction. @warning This method may only be called during a write transaction. */ - (void)cancelWriteTransaction; /** Performs actions contained within the given block inside a write transaction. @see `[RLMRealm transactionWithoutNotifying:block:error:]` */ - (void)transactionWithBlock:(__attribute__((noescape)) void(^)(void))block NS_SWIFT_UNAVAILABLE(""); /** Performs actions contained within the given block inside a write transaction. @see `[RLMRealm transactionWithoutNotifying:block:error:]` */ - (BOOL)transactionWithBlock:(__attribute__((noescape)) void(^)(void))block error:(NSError **)error; /** Performs actions contained within the given block inside a write transaction. @see `[RLMRealm transactionWithoutNotifying:block:error:]` */ - (void)transactionWithoutNotifying:(NSArray *)tokens block:(__attribute__((noescape)) void(^)(void))block; /** Performs actions contained within the given block inside a write transaction. Write transactions cannot be nested, and trying to execute a write transaction on a Realm which is already participating in a write transaction will throw an exception. Calls to `transactionWithBlock:` from `RLMRealm` instances in other threads will block until the current write transaction completes. Before beginning the write transaction, `transactionWithBlock:` updates the `RLMRealm` instance to the latest Realm version, as if `refresh` had been called, and generates notifications if applicable. This has no effect if the Realm was already up to date. You can skip notifiying specific notification blocks about the changes made in this write transaction by passing in their associated notification tokens. This is primarily useful when the write transaction is saving changes already made in the UI and you do not want to have the notification block attempt to re-apply the same changes. The tokens passed to this method must be for notifications for this specific `RLMRealm` instance. Notifications for different threads cannot be skipped using this method. @param tokens An array of notification tokens which were returned from adding callbacks which you do not want to be notified for the changes made in this write transaction. @param block The block containing actions to perform. @param error If an error occurs, upon return contains an `NSError` object that describes the problem. If you are not interested in possible errors, pass in `NULL`. @return Whether the transaction succeeded. */ - (BOOL)transactionWithoutNotifying:(NSArray *)tokens block:(__attribute__((noescape)) void(^)(void))block error:(NSError **)error; /** Updates the Realm and outstanding objects managed by the Realm to point to the most recent data. If the version of the Realm is actually changed, Realm and collection notifications will be sent to reflect the changes. This may take some time, as collection notifications are prepared on a background thread. As a result, calling this method on the main thread is not advisable. @return Whether there were any updates for the Realm. Note that `YES` may be returned even if no data actually changed. */ - (BOOL)refresh; /** Set this property to `YES` to automatically update this Realm when changes happen in other threads. If set to `YES` (the default), changes made on other threads will be reflected in this Realm on the next cycle of the run loop after the changes are committed. If set to `NO`, you must manually call `-refresh` on the Realm to update it to get the latest data. Note that by default, background threads do not have an active run loop and you will need to manually call `-refresh` in order to update to the latest version, even if `autorefresh` is set to `YES`. Even with this property enabled, you can still call `-refresh` at any time to update the Realm before the automatic refresh would occur. Write transactions will still always advance a Realm to the latest version and produce local notifications on commit even if autorefresh is disabled. Disabling `autorefresh` on a Realm without any strong references to it will not have any effect, and `autorefresh` will revert back to `YES` the next time the Realm is created. This is normally irrelevant as it means that there is nothing to refresh (as managed `RLMObject`s, `RLMArray`s, and `RLMResults` have strong references to the Realm that manages them), but it means that setting `RLMRealm.defaultRealm.autorefresh = NO` in `application:didFinishLaunchingWithOptions:` and only later storing Realm objects will not work. Defaults to `YES`. */ @property (nonatomic) BOOL autorefresh; /** Invalidates all `RLMObject`s, `RLMResults`, `RLMLinkingObjects`, and `RLMArray`s managed by the Realm. A Realm holds a read lock on the version of the data accessed by it, so that changes made to the Realm on different threads do not modify or delete the data seen by this Realm. Calling this method releases the read lock, allowing the space used on disk to be reused by later write transactions rather than growing the file. This method should be called before performing long blocking operations on a background thread on which you previously read data from the Realm which you no longer need. All `RLMObject`, `RLMResults` and `RLMArray` instances obtained from this `RLMRealm` instance on the current thread are invalidated. `RLMObject`s and `RLMArray`s cannot be used. `RLMResults` will become empty. The Realm itself remains valid, and a new read transaction is implicitly begun the next time data is read from the Realm. Calling this method multiple times in a row without reading any data from the Realm, or before ever reading any data from the Realm, is a no-op. */ - (void)invalidate; #pragma mark - Accessing Objects /** Returns the same object as the one referenced when the `RLMThreadSafeReference` was first created, but resolved for the current Realm for this thread. Returns `nil` if this object was deleted after the reference was created. @param reference The thread-safe reference to the thread-confined object to resolve in this Realm. @warning A `RLMThreadSafeReference` object must be resolved at most once. Failing to resolve a `RLMThreadSafeReference` will result in the source version of the Realm being pinned until the reference is deallocated. An exception will be thrown if a reference is resolved more than once. @warning Cannot call within a write transaction. @note Will refresh this Realm if the source Realm was at a later version than this one. @see `+[RLMThreadSafeReference referenceWithThreadConfined:]` */ - (nullable id)resolveThreadSafeReference:(RLMThreadSafeReference *)reference NS_REFINED_FOR_SWIFT; #pragma mark - Adding and Removing Objects from a Realm /** Adds an object to the Realm. Once added, this object is considered to be managed by the Realm. It can be retrieved using the `objectsWhere:` selectors on `RLMRealm` and on subclasses of `RLMObject`. When added, all child relationships referenced by this object will also be added to the Realm if they are not already in it. If the object or any related objects are already being managed by a different Realm an exception will be thrown. Use `-[RLMObject createInRealm:withObject:]` to insert a copy of a managed object into a different Realm. The object to be added must be valid and cannot have been previously deleted from a Realm (i.e. `isInvalidated` must be `NO`). @warning This method may only be called during a write transaction. @param object The object to be added to this Realm. */ - (void)addObject:(RLMObject *)object; /** Adds all the objects in a collection to the Realm. This is the equivalent of calling `addObject:` for every object in a collection. @warning This method may only be called during a write transaction. @param objects An enumerable collection such as `NSArray`, `RLMArray`, or `RLMResults`, containing Realm objects to be added to the Realm. @see `addObject:` */ - (void)addObjects:(id)objects; /** Adds or updates an existing object into the Realm. The object provided must have a designated primary key. If no objects exist in the Realm with the same primary key value, the object is inserted. Otherwise, the existing object is updated with any changed values. As with `addObject:`, the object cannot already be managed by a different Realm. Use `-[RLMObject createOrUpdateInRealm:withValue:]` to copy values to a different Realm. If there is a property or KVC value on `object` whose value is nil, and it corresponds to a nullable property on an existing object being updated, that nullable property will be set to nil. @warning This method may only be called during a write transaction. @param object The object to be added or updated. */ - (void)addOrUpdateObject:(RLMObject *)object; /** Adds or updates all the objects in a collection into the Realm. This is the equivalent of calling `addOrUpdateObject:` for every object in a collection. @warning This method may only be called during a write transaction. @param objects An enumerable collection such as `NSArray`, `RLMArray`, or `RLMResults`, containing Realm objects to be added to or updated within the Realm. @see `addOrUpdateObject:` */ - (void)addOrUpdateObjects:(id)objects; /** Deletes an object from the Realm. Once the object is deleted it is considered invalidated. @warning This method may only be called during a write transaction. @param object The object to be deleted. */ - (void)deleteObject:(RLMObject *)object; /** Deletes one or more objects from the Realm. This is the equivalent of calling `deleteObject:` for every object in a collection. @warning This method may only be called during a write transaction. @param objects An enumerable collection such as `NSArray`, `RLMArray`, or `RLMResults`, containing objects to be deleted from the Realm. @see `deleteObject:` */ - (void)deleteObjects:(id)objects; /** Deletes all objects from the Realm. @warning This method may only be called during a write transaction. @see `deleteObject:` */ - (void)deleteAllObjects; #pragma mark - Migrations /** The type of a migration block used to migrate a Realm. @param migration A `RLMMigration` object used to perform the migration. The migration object allows you to enumerate and alter any existing objects which require migration. @param oldSchemaVersion The schema version of the Realm being migrated. */ typedef void (^RLMMigrationBlock)(RLMMigration *migration, uint64_t oldSchemaVersion); /** Returns the schema version for a Realm at a given local URL. @param fileURL Local URL to a Realm file. @param key 64-byte key used to encrypt the file, or `nil` if it is unencrypted. @param error If an error occurs, upon return contains an `NSError` object that describes the problem. If you are not interested in possible errors, pass in `NULL`. @return The version of the Realm at `fileURL`, or `RLMNotVersioned` if the version cannot be read. */ + (uint64_t)schemaVersionAtURL:(NSURL *)fileURL encryptionKey:(nullable NSData *)key error:(NSError **)error NS_REFINED_FOR_SWIFT; /** Performs the given Realm configuration's migration block on a Realm at the given path. This method is called automatically when opening a Realm for the first time and does not need to be called explicitly. You can choose to call this method to control exactly when and how migrations are performed. @param configuration The Realm configuration used to open and migrate the Realm. @return The error that occurred while applying the migration, if any. @see RLMMigration */ + (BOOL)performMigrationForConfiguration:(RLMRealmConfiguration *)configuration error:(NSError **)error; #pragma mark - Unavailable Methods /** RLMRealm instances are cached internally by Realm and cannot be created directly. Use `+[RLMRealm defaultRealm]`, `+[RLMRealm realmWithConfiguration:error:]` or `+[RLMRealm realmWithURL]` to obtain a reference to an RLMRealm. */ - (instancetype)init __attribute__((unavailable("Use +defaultRealm, +realmWithConfiguration: or +realmWithURL:."))); /** RLMRealm instances are cached internally by Realm and cannot be created directly. Use `+[RLMRealm defaultRealm]`, `+[RLMRealm realmWithConfiguration:error:]` or `+[RLMRealm realmWithURL]` to obtain a reference to an RLMRealm. */ + (instancetype)new __attribute__((unavailable("Use +defaultRealm, +realmWithConfiguration: or +realmWithURL:."))); /// :nodoc: - (void)addOrUpdateObjectsFromArray:(id)array __attribute__((unavailable("Renamed to -addOrUpdateObjects:."))); @end // MARK: - RLMNotificationToken /** A token which is returned from methods which subscribe to changes to a Realm. Change subscriptions in Realm return an `RLMNotificationToken` instance, which can be used to unsubscribe from the changes. You must store a strong reference to the token for as long as you want to continue to receive notifications. When you wish to stop, call the `-invalidate` method. Notifications are also stopped if the token is deallocated. */ @interface RLMNotificationToken : NSObject /// Stops notifications for the change subscription that returned this token. - (void)invalidate; /// Stops notifications for the change subscription that returned this token. - (void)stop __attribute__((unavailable("Renamed to -invalidate."))) NS_REFINED_FOR_SWIFT; @end NS_ASSUME_NONNULL_END