Kotlin

Description — Couchbase Lite for Android — Kotlin support
Related Content — Databases | Documents | Indexing |

Introduction

Couchbase Lite Android 3.1.9 introduces full idiomatic support for Kotlin apps, out-of-the-box.

Kotlin developers can now build apps using common Kotlin Patterns, that integrate seamlessly with Couchbase Lite for Android and have full feature parity with the Java API; including some convenient Kotlin Extensions to get you started.

Key features include:

Nullability annotations
Named parameters
Kotlin Flows, for asynchronous event notifications

Java support and functionality continues for Android.

Kotlin Extensions

In addition to having full co-compatible access to the existing Java API, Kotlin developers can also access a number of Kotlin Extensions.

The Kotlin Extensions package includes:

Configuration Factories for the configuration of important Couchbase Lite objects such as Databases, Replicators and Listeners.
Change Flows that monitor key Couchbase Lite objects fpr change using Kotlin features such as, Co-routines and Flows.

See: Kotlin Extensions for extension API docs

Configuration Factories

Couchbase Lite provides a set of ConfigurationFactories and CommonConfigurationFactories, these allow use of named parameters to specify property settings.

This makes it simple to create variant configurations, by simply overriding named parameters:

Example of overriding configuration

val listener8080 = URLEndpointListenerConfigurationFactory.newConfig(
    networkInterface = "en0",
    port = 8080
)
val listener8081 = listener8080.newConfig(port = 8081)

Database

Use DatabaseConfigurationFactory to create a DatabaseConfiguration object, overriding the receiver’s values with the passed parameters.

In Use
Definition

database = Database("getting-started")

val DatabaseConfigurationFactory: DatabaseConfiguration? = null

fun DatabaseConfiguration?.create(
    databasePath: String? = null,
    encryptionKey: EncryptionKey? = null
)

Replication

Use ReplicatorConfigurationFactory to create a ReplicatorConfiguration object, overriding the receiver’s values with the passed parameters.

In Use
Definition

val replicator =
    Replicator(
        ReplicatorConfigurationFactory.newConfig(
            collections = mapOf(db.collections to null),
            target = URLEndpoint(URI("ws://localhost:4984/getting-started-db")),
            type = ReplicatorType.PUSH_AND_PULL,
            authenticator = BasicAuthenticator("sync-gateway", "password".toCharArray())
        )
    )

val ReplicatorConfigurationFactory: ReplicatorConfiguration? = null

fun ReplicatorConfiguration?.create(
    database: Database? = null,
    target: Endpoint? = null,
    type: ReplicatorType? = null,
    continuous: Boolean? = null,
    authenticator: Authenticator? = null,
    headers: Map<String, String>? = null,
    pinnedServerCertificate: ByteArray? = null,
    channels: List<String>? = null,
    documentIDs: List<String>? = null,
    pushFilter: ReplicationFilter? = null,
    pullFilter: ReplicationFilter? = null,
    conflictResolver: ConflictResolver? = null,
    maxAttempts: Int? = null,
    maxAttemptWaitTime: Int? = null,
    heartbeat: Int? = null,
    enableAutoPurge: Boolean? = null,
    acceptOnlySelfSignedServerCertificate: Boolean? = null
)

val MessageEndpointListenerConfigurationFactory: MessageEndpointListenerConfiguration? = null

fun MessageEndpointListenerConfiguration?.create(
    database: Database? = null,
    protocolType: ProtocolType? = null
)

Full Text Search

Use FullTextIndexConfigurationFactory to create a FullTextIndexConfiguration object, overriding the receiver’s values with the passed parameters.

In Use
Definition

collection.createIndex(
    "overviewFTSIndex",
    FullTextIndexConfigurationFactory.newConfig("overview"))

val FullTextIndexConfigurationFactory: FullTextIndexConfiguration? = null

fun FullTextIndexConfiguration?.create(expression: String? = null)

Indexing

Use ValueIndexConfigurationFactory to create a ValueIndexConfiguration object, overriding the receiver’s values with the passed parameters.

In Use
Definition

collection.createIndex(
    "TypeNameIndex",
    ValueIndexConfigurationFactory.newConfig("type", "name")
)

val ValueIndexConfigurationFactory: ValueIndexConfiguration? = null

fun ValueIndexConfiguration?.create(vararg expressions: String = emptyArray())

Logs

Use LogFileConfigurationFactory to create a LogFileConfiguration object, overriding the receiver’s values with the passed parameters.

In Use
Definition

Database.log.file.let {
    it.config = LogFileConfigurationFactory.newConfig(
        context.cacheDir.absolutePath, (1)
        maxSize = 10240, (2)
        maxRotateCount = 5, (3)
        usePlainText = false
    ) (4)
    it.level = LogLevel.INFO (5)

}

val LogFileConfigurationFactory: LogFileConfiguration? = null

.LogFileConfiguration.create()

fun LogFileConfiguration?.create(
    directory: String? = null,
    maxSize: Long? = null,
    maxRotateCount: Int? = null,
    usePlainText: Boolean? = null
)

Flows

These wrappers use Flowables to monitor for changes.

Database Change Flow

Use the databaseChangeFlow(Database,Executor) to monitor database change events.

In Use
Definition

val updatedDocs = db.databaseChangeFlow()
    .map { it.documentIDs }
    .asLiveData()

@ExperimentalCoroutinesApi
fun Database.databaseChangeFlow(executor: Executor? = null)

Document Change Flow

Use documentChangeFlow(Database,String,Executor) to monitor changes to a document.

In Use
Definition

val docModDate = db.documentChangeFlow("1001", null)
    .map { it.collection.getDocument(it.documentID)?.getString("lastModified") }
    .asLiveData()

@ExperimentalCoroutinesApi

fun Database.documentChangeFlow(documentId: String, executor: Executor? = null)

Replicator Change Flow

Use replicatorChangeFlow(Replicator,Executor) to monitor replicator changes.

In Use
Definition

val replState = repl.replicatorChangesFlow()
    .map { it.status.activityLevel }
    .asLiveData()

@ExperimentalCoroutinesApi
fun Replicator.replicatorChangesFlow(executor: Executor? = null)

Document Replicator Change Flow

Use documentReplicationFlow(Replicator,Executor) to monitor document changes during replication.

In Use
Definition

val replicatedDocs = repl.documentReplicationFlow(testSerialExecutor)
    .map { update -> update.documents }
    .onEach { listView.setUpdated(it) }
    .collect()

@ExperimentalCoroutinesApi
fun Replicator.documentReplicationFlow(executor: Executor? = null)

Query Change Flow

Use queryChangeFlow(Query,Executor) to monitor document changes during replication.

In Use
Definition

fun watchQuery(query: Query): LiveData<List<Result>> {
    return query.queryChangeFlow()
        .mapNotNull { change ->
            val err = change.error
            if (err != null) {
                throw err
            }
            change.results?.allResults()
        }
        .asLiveData()
}

@ExperimentalCoroutinesApi
fun Query.queryChangeFlow(executor: Executor? = null)

How to . . .

Learn more . . .

Dive Deeper . . .

Mobile Forum | Blog | Tutorials