datastore-core/androidx.datastore.core

Package-level declarations

Types

Datastore common version of java.io.Closeable

class CorruptionException(message: String, cause: Throwable? = null) : IOException

A subclass of IOException that indicates that the file could not be de-serialized due to data format corruption. This exception should not be thrown when the IOException is due to a transient IO issue or permissions issue.

DataMigration

interface DataMigration<T>

Interface for migrations to DataStore. Methods on this migration (shouldMigrate, migrate and cleanUp) may be called multiple times, so their implementations must be idempotent. These methods may be called multiple times if DataStore encounters issues when writing the newly migrated data to disk or if any migration installed in the same DataStore throws an Exception.

DataStore

interface DataStore<T>

DataStore provides a safe and durable way to store small amounts of data, such as preferences and application state. It does not support partial updates: if any field is modified, the whole object will be serialized and persisted to disk. If you want partial updates, consider the Room API (SQLite).

DataStoreFactory

expect object DataStoreFactory

actual object DataStoreFactory

Public factory for creating DataStore instances.

actual object DataStoreFactory

Public factory for creating DataStore instances.

FileStorage

@RestrictTo(value = [RestrictTo.Scope.LIBRARY_GROUP])

class FileStorage<T>(serializer: Serializer<T>, produceFile: () -> File) : Storage<T>

The Java IO File version of the Storage interface. Is able to read and write T to a given file location.

IOException

expect open class IOException(message: String?, cause: Throwable?)

Common IOException to be defined in jvm and native code.

actual typealias IOException = IOException

actual open class IOException(message: String?, cause: Throwable?)

Common IOException mapped to a custom exception class in native code.

ReadScope

interface ReadScope<T> : Closeable

The scope used for a read transaction.

Serializer

interface Serializer<T>

The serializer determines the on-disk format and API for accessing it.

Storage

interface Storage<T>

Storage provides a way to create StorageConnections that allow read and write a particular type of data. Storage is used to construct DataStore objects, and encapsulates all the specifics of the data format and persistence.

StorageConnection

interface StorageConnection<T> : Closeable

StorageConnection provides a way to read and write a particular type of data. StorageConnections are created from Storage objects.

WriteScope

interface WriteScope<T> : ReadScope<T>

The scope used for a write transaction.

Functions

readData

suspend fun <T> StorageConnection<T>.readData(): T

use

inline fun <T : Closeable, R> T.use(block: (T) -> R): R

Ensures a Closeable object has its close() method called at the end of the supplied block.

writeData

suspend fun <T> StorageConnection<T>.writeData(value: T)