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Add observability via MetaRef

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This commit is contained in:
Alexander Nozik 2024-07-22 12:20:05 +03:00
parent 8723f49efd
commit 904262a22a
1 changed files with 19 additions and 0 deletions
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19
dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/MetaRef.kt
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@ -7,6 +7,7 @@ import space.kscience.dataforge.meta.descriptors.MetaDescriptorBuilder
import space.kscience.dataforge.misc.DFExperimental
import space.kscience.dataforge.names.Name
import space.kscience.dataforge.names.asName
import space.kscience.dataforge.names.startsWith
import kotlin.properties.PropertyDelegateProvider
import kotlin.properties.ReadOnlyProperty
@ -35,6 +36,24 @@ public operator fun <T> MutableMetaProvider.set(ref: MetaRef<T>, value: T) {
set(ref.name, ref.converter.convert(value))
}
/**
* Observe changes to specific property via given [ref].
*
* This listener should be removed in a same way as [ObservableMeta.onChange].
*
* @param callback an action to be performed on each change of item. Null means that the item is not present or malformed.
*/
@DFExperimental
public fun <T: Any> ObservableMeta.onValueChange(owner: Any?, ref: MetaRef<T>, callback: (T?) -> Unit) {
onChange(owner) { name ->
if (name.startsWith(ref.name)) {
get(name)?.let { value ->
callback(ref.converter.readOrNull(value))
}
}
}
}
/**
* Remove a node corresponding to [ref] from a mutable provider if it exists
*/