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package sims.test.gui
import scala.collection.mutable.ListBuffer
import sims.dynamics._
trait Event
case class BodyAdded(world: World, body: Body) extends Event
case class BodyRemoved(world: World, body: Body) extends Event
case class Stepped(wordl: World) extends Event
case class JointAdded(world: World, joint: Joint) extends Event
case class JointRemoved(world: World, joint: Joint) extends Event
object Reactions {
class Impl extends Reactions {
private val parts = new ListBuffer[Reaction]
def isDefinedAt(e: Event) = parts exists (_ isDefinedAt e)
def +=(r: Reaction) = parts += r
def -=(r: Reaction) = parts -= r
def clear() = parts.clear()
def apply(e: Event) {
for (p <- parts; if p isDefinedAt e) p(e)
}
}
type Reaction = PartialFunction[Event, Unit]
}
abstract class Reactions extends Reactions.Reaction {
def +=(r: Reactions.Reaction): Unit
def -=(r: Reactions.Reaction): Unit
def clear(): Unit
}
trait Reactor {
val reactions: Reactions = new Reactions.Impl
def listenTo(ps: Publisher*) = for (p <- ps) p.subscribe(reactions)
def deafTo(ps: Publisher*) = for (p <- ps) p.unsubscribe(reactions)
}
trait Publisher {
import Reactions._
private val listeners = new ListBuffer[Reaction]
def subscribe(listener: Reaction) = listeners += listener
def unsubscribe(listener: Reaction) = listeners -= listener
def publish(e: Event) { for (l <- listeners) l(e) }
}
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