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package mx.trackermap.TrackerMap.client.infrastructure
import kotlin.properties.ReadWriteProperty
import kotlin.reflect.KProperty
object ApplicationDelegates {
/**
* Provides a property delegate, allowing the property to be set once and only once.
*
* If unset (no default value), a get on the property will throw [IllegalStateException].
*/
fun <T> setOnce(defaultValue: T? = null): ReadWriteProperty<Any?, T> = SetOnce(defaultValue)
private class SetOnce<T>(defaultValue: T? = null) : ReadWriteProperty<Any?, T> {
private var isSet = false
private var value: T? = defaultValue
override fun getValue(thisRef: Any?, property: KProperty<*>): T {
return value ?: throw IllegalStateException("${property.name} not initialized")
}
override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) = synchronized(this) {
if (!isSet) {
this.value = value
isSet = true
}
}
}
}
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