reactify.reaction.Reaction.scala Maven / Gradle / Ivy
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package reactify.reaction
import reactify.Priority
/**
* Reaction may be thought of similar to `Observer` or `Listener` in other libraries. A Reaction may be added to a
* Reactive in order react when a value is fired upon it.
*
* @tparam T the type received by this Reaction
*/
trait Reaction[T] extends Ordered[Reaction[T]] {
/**
* Invoked when a new value is received by the associated Reactive
*
* @param value the new value
* @param previous the previous value, if one was defined
* @return
*/
def apply(value: T, previous: Option[T]): ReactionStatus
/**
* Priority of this Reaction in contrast to other Reactions attached to the same Reactive. A higher value represents
* a higher position in reactions list. See Priority for pre-defined values.
*/
def priority: Double = Priority.Normal
override def compare(that: Reaction[T]): Int = this.priority.compare(that.priority)
}
object Reaction {
def apply[T](f: T => Unit, priority: Double = Priority.Normal): Reaction[T] = FunctionReaction[T](f, priority)
def changes[T](f: (T, T) => Unit, priority: Double = Priority.Normal): Reaction[T] = {
ChangeFunctionReaction[T](f, priority)
}
}