scalafx-utils/src/main/scala/org/gerweck/scalafx/util/prefs/ObservablePref.scala

// package org.gerweck.scalafx.util
// package prefs

// import java.util.prefs._

// import scalafx.application.Platform.runLater
// import scalafx.beans.property.ObjectProperty

// import org.gerweck.scala.util.prefs._

// /* TODO: take an implicit that will deteremine whether this is an `ObjectProperty` or what */
// class ObservablePref[A] protected (path: String)(implicit handler: Pref.AccessHandler[A], prefs: Preferences)
//     extends Pref[A](path) { thisPref =>

//   lazy val observe: ObjectProperty[A] = {
//     val initialValue: A = this()
//     val property = ObjectProperty[A](initialValue)

//     /* We build two bridges, one that listens for changes in the preferences system and pushes
//      * them into the observable property, and another that listens for updates to the property and
//      * pushes them to the preference system. Each bridge is gated so that it only activates if the
//      * value has actually changed, which prevents the infinite looping that would otherwise occur
//      * in a bidirectional bridge. */

//     /* Preferences => Property bridge */

//     /* In Scala 2.12, the callback could just be bare inside `addPreferenceChangeListener`.
//      * However, it must be created explicitly since we cross-compile against Scala 2.11. */
//     val changeListener = new PreferenceChangeListener {
//       def preferenceChange(pce: PreferenceChangeEvent): Unit = {
//         if (pce.getKey == path) {
//           runLater {
//             val currentValue = thisPref()
//             if (property.value != currentValue) {
//               property.value = currentValue
//             }
//           }
//         }
//       }
//     }
//     prefs.addPreferenceChangeListener(changeListener)

//     /* Property => Preferences bridge */
//     property.onChange { (_, _, newV) =>
//       if (newV != this()) {
//         this() = newV
//       }
//     }

//     /* Return the bridged property */
//     property
//   }
// }

// object ObservablePref {
//   def apply[A](path: String)(implicit handler: PrefHandler[A], prefs: Preferences) = {
//     new ObservablePref(path)(new Pref.AccessHandler.Optional, prefs)
//   }
//   def apply[A](path: String, default: A)(implicit handler: PrefHandler[A], prefs: Preferences) = {
//     new ObservablePref(path)(new Pref.AccessHandler.Defaulted(default), prefs)
//   }
// }