kform/tech.ostack.kform/ComputedValue

ComputedValue

abstract class ComputedValue<out T> : Computation(source)

Computed value for values of type T.

Computed values should depend on other values. These dependencies may be defined via the dependency function, by providing the path of the dependency relative to the value being computed.

Example computed value which computes the sum between two other values:

object MySum : ComputedValue<Int>() {
    private val ComputedValueContext.value1: Int? by dependency("../value1")
    private val ComputedValueContext.value2: Int? by dependency("../value2")

    override suspend fun ComputedValueContext.compute(): Int = (value1 ?: 0) + (value2 ?: 0)
}

Inheritors

StatefulComputedValue

Constructors

ComputedValue

constructor()

Properties

dependencies

open override val dependencies: Map<String, DependencyInfo>

Dependencies of the computed value. Mapping of keys to the paths this computed value depends on. Keys can be used within a ComputedValueContext to access the value of the dependencies.

externalContextDependencies

open override val externalContextDependencies: Set<String>

Set of external context dependencies of the computed value.

schema

protected val ComputedValueContext.schema: Schema<T>

Schema of the value being computed.

Functions

addDependency

@JvmName(name = "reifiedAddDependency")

protected inline fun <TDependency> addDependency(dependencyKey: String, path: String)

protected fun addDependency(dependencyKey: String, path: String)

@JvmName(name = "reifiedAddDependency")

protected inline fun <TDependency> addDependency(dependencyKey: String, path: Path)

protected fun addDependency(dependencyKey: String, path: Path)

Declares a dependency to path, accessible in the computed value's context via key dependencyKey.

addExternalContextDependency

protected fun addExternalContextDependency(externalContextName: String)

Declares an external context dependency to externalContextName.

compute

abstract suspend fun ComputedValueContext.compute(): T

Runs the computation within a ComputedValueContext containing the value of all declared dependencies. Returns the computed value.

dependency

protected inline fun <TDependency> dependency(path: String, dependencyKey: String? = null): PropertyDelegateProvider<ComputedValue<T>, ReadOnlyProperty<ComputedValueContext, TDependency>>

protected inline fun <TDependency> dependency(path: Path, dependencyKey: String? = null): PropertyDelegateProvider<ComputedValue<T>, ReadOnlyProperty<ComputedValueContext, TDependency>>

Function used to declare a dependency to a path and delegate access to its value within a ComputedValueContext.

dependencyOrNull

protected inline fun <TDependency> dependencyOrNull(path: String, dependencyKey: String? = null): PropertyDelegateProvider<ComputedValue<T>, ReadOnlyProperty<ComputedValueContext, TDependency?>>

protected inline fun <TDependency> dependencyOrNull(path: Path, dependencyKey: String? = null): PropertyDelegateProvider<ComputedValue<T>, ReadOnlyProperty<ComputedValueContext, TDependency?>>

Function used to declare a dependency to a path and delegate access to its value within a ComputedValueContext.

externalContext

protected fun <TContext> externalContext(externalContextName: String? = null): PropertyDelegateProvider<ComputedValue<T>, ReadOnlyProperty<ComputedValueContext, TContext>>

Function used to declare a dependency to an external context and delegate access to its value within a ComputedValueContext.

externalContextOrNull

protected fun <TContext> externalContextOrNull(externalContextName: String? = null): PropertyDelegateProvider<ComputedValue<T>, ReadOnlyProperty<ComputedValueContext, TContext?>>

Function used to declare a dependency to an external context and delegate access to its value within a ComputedValueContext.

toString

open override fun toString(): String