Class RealmConfiguration.Builder

Sets whether or not a RealmQuery can be launched from the UI thread.

By default Realm allows queries on the main thread. However, by doing so your application may experience a drop of frames or even ANRs. We recommend diverting queries to non-UI threads or, alternatively, using RealmQuery.findAllAsync() or RealmQuery.findFirstAsync() .

Sets whether or not calls to Realm.executeTransaction are allowed from the UI thread.

WARNING: Realm does not allow synchronous transactions to be run on the main thread unless users explicitly opt in with this method. We recommend diverting calls to executeTransaction to non-UI threads or, alternatively, using Realm.executeTransactionAsync .

Copies the Realm file from the given asset file path.When opening the Realm for the first time, instead of creating an empty file, the Realm file will be copied from the provided asset file and used instead.

This cannot be combined with deleteRealmIfMigrationNeeded() as doing so would just result in the copied file being deleted.

WARNING: This could potentially be a lengthy operation and should ideally be done on a background thread.

Parameters

• assetFile - path to the asset database file.

Throws

• IllegalStateException - if this is configured to clear its schema by calling deleteRealmIfMigrationNeeded() .

Creates the RealmConfiguration based on the builder parameters.

Returns

the created RealmConfiguration .

Sets this to determine if the Realm file should be compacted before returned to the user. It is passed the total file size (data + free space) and the bytes used by data in the file.

Parameters

• compactOnLaunch - a callback called when opening a Realm for the first time during the life of a process to determine if it should be compacted before being returned to the user. It is passed the total file size (data + free space) and the bytes used by data in the file.

Setting this will change the behavior of how migration exceptions are handled. Instead of throwing a io.realm.exceptions.RealmMigrationNeededException the on-disc Realm will be cleared and recreated with the new Realm schema.

This cannot be configured to have an asset file at the same time by calling assetFile(String) as the provided asset file will be deleted in migrations.

WARNING! This will result in loss of data.

Throws

• IllegalStateException - if configured to use an asset file by calling assetFile(String) previously.

Specifies the directory where the Realm file will be saved. The default value is context.getFilesDir() . If the directory does not exist, it will be created.

Parameters

• directory - the directory to save the Realm file in. Directory must be writable.

Throws

• IllegalArgumentException - if directory is null, not writable or a file.

Sets the FlowFactory used to create coroutines Flows from Realm objects. The default factory is RealmFlowFactory .

Parameters

• factory - factory to use.

Sets the initial data in io.realm.Realm . This transaction will be executed only for the first time when database file is created or while migrating the data when Builder.deleteRealmIfMigrationNeeded() is set.

Parameters

• transaction - transaction to execute.

Sets the maximum number of live versions in the Realm file before an IllegalStateException is thrown when attempting to write more data.

Realm is capable of concurrently handling many different versions of Realm objects. This can e.g. happen if you have a Realm open on many different threads or are freezing objects while data is being written to the file.

Under normal circumstances this is not a problem, but if the number of active versions grow too large, it will have a negative effect on the filesize on disk. Setting this parameters can therefore be used to prevent uses of Realm that can result in very large Realms.

Parameters

• number - the maximum number of active versions before an exception is thrown.

Replaces the existing module(s) with one or more RealmModule s. Using this method will replace the current schema for this Realm with the schema defined by the provided modules.

A reference to the default Realm module containing all Realm classes in the project (but not dependencies), can be found using Realm.getDefaultModule() . Combining the schema from the app project and a library dependency is thus done using the following code:

builder.modules(Realm.getDefaultMode(), new MyLibraryModule());

Parameters

• baseModule - the first Realm module (required).

• additionalModules - the additional Realm modules

Throws

• IllegalArgumentException - if any of the modules doesn't have the RealmModule annotation.

Setting this will cause the Realm to become read only and all write transactions made against this Realm will fail with an IllegalStateException .

This in particular mean that initialData(Realm.Transaction) will not work in combination with a read only Realm and setting this will result in a IllegalStateException being thrown.

Marking a Realm as read only only applies to the Realm in this process. Other processes can still write to the Realm.

Sets the RxObservableFactory used to create Rx Observables from Realm objects. The default factory is RealmObservableFactory .

Parameters

• factory - factory to use.

Sets the schema version of the Realm. This must be equal to or higher than the schema version of the existing Realm file, if any. If the schema version is higher than the already existing Realm, a migration is needed.If no migration code is provided, Realm will throw a io.realm.exceptions.RealmMigrationNeededException .