sdbus-kotlin/com.monkopedia.sdbus/PropertyDelegate

PropertyDelegate

open class PropertyDelegate<R, T : Any>(proxy: Proxy, val interfaceName: InterfaceName, val propertyName: PropertyName, type: KSerializer<T>, module: SerializersModule, signature: TypeSignature) : ReadOnlyProperty<R, T>

A read-only Kotlin property delegate backed by a D-Bus property.

Reading the delegated property issues a D-Bus Get. The delegate also offers convenience accessors (getOrNull, await) and reactive observation of the property (changes, values, changesOrNull, valuesOrNull). Obtain one via Proxy.propDelegate.

The observation methods come in two families:

changes/changesOrNull emit change events only — nothing is emitted until the property changes after collection starts.
values/valuesOrNull emit the current value first, then all subsequent changes.

Each family has a throwing and a nullable variant: get, changes and values surface a missing/invalidated property as an exception or by dropping the event, while getOrNull, changesOrNull and valuesOrNull represent it as null.

Inheritors

MutablePropertyDelegate

Constructors

PropertyDelegate

constructor(proxy: Proxy, interfaceName: InterfaceName, propertyName: PropertyName, type: KSerializer<T>, module: SerializersModule, signature: TypeSignature)

Properties

interfaceName

val interfaceName: InterfaceName

Interface that declares the property

propertyName

val propertyName: PropertyName

Name of the property

Functions

await

suspend fun await(): T

Waits for the property to be present and returns the first value when it is. If the property is currently valid, then it is returned immediately.

changes

fun changes(): Flow<T>

Produces a flow that observes the PropertiesChanged signal and emits the new value of this property each time it changes.

changesOrNull

fun changesOrNull(): Flow<T?>

Like changes but also emits null whenever the property has been invalidated (i.e. it appears in the invalidatedProperties of a PropertiesChanged signal), instead of dropping the event.

get

fun get(): T

Gets the current value of the property.

getOrNull

fun getOrNull(): T?

Gets the current value of the property, however if the property doesn't currently exist (org.freedesktop.DBus.Error.InvalidArgs), returns null rather than throwing. Any other com.monkopedia.sdbus.SdbusException is still thrown.

getValue

open operator override fun getValue(thisRef: R, property: KProperty<*>): T

values

fun values(): Flow<T>

Produces a flow of all values of the property: the current value (from get) is emitted first when collection starts, followed by every subsequent change (from changes).

valuesOrNull

fun valuesOrNull(): Flow<T?>

Like values but null-safe: the current value (from getOrNull, null if the property doesn't currently exist) is emitted first when collection starts, followed by every subsequent change (from changesOrNull, which emits null on invalidation).