de.sciss.mellite.gui.DragAndDrop.scala Maven / Gradle / Ivy

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/*
 *  DragAndDrop.scala
 *  (Mellite)
 *
 *  Copyright (c) 2012-2016 Hanns Holger Rutz. All rights reserved.
 *
 *  This software is published under the GNU General Public License v3+
 *
 *
 *  For further information, please contact Hanns Holger Rutz at
 *  [email protected]
 */

package de.sciss
package mellite
package gui

import java.awt.datatransfer.{UnsupportedFlavorException, Transferable, DataFlavor}

import collection.breakOut

object DragAndDrop {
  sealed trait Flavor[+A] extends DataFlavor

  def internalFlavor[A](implicit ct: reflect.ClassTag[A]): Flavor[A] =
    new DataFlavor(DataFlavor.javaJVMLocalObjectMimeType + ";class=\"" + ct.runtimeClass.getName + "\"") with Flavor[A]

  object Transferable {
    /** Creates a transferable for one particular flavor. */
    def apply[A](flavor: Flavor[A])(data: A): Transferable = new Transferable {
      override def toString = s"Transferable($data)"

      // private val flavor = internalFlavor[A]
      // println(s"My flavor is $flavor")
      def getTransferDataFlavors: Array[DataFlavor] = Array(flavor) // flavors.toArray
      def isDataFlavorSupported(_flavor: DataFlavor): Boolean = {
        import equal.Implicits._
        _flavor === flavor
      }
      def getTransferData(_flavor: DataFlavor): AnyRef  = {
        if (!isDataFlavorSupported(_flavor)) throw new UnsupportedFlavorException(_flavor)
        data  /* .getOrElse(throw new IOException()) */ .asInstanceOf[AnyRef]
      }
    }

    /** Creates a transferable by wrapping a sequence of existing transferables. */
    def seq(xs: Transferable*): Transferable = new Transferable {
      def getTransferDataFlavors: Array[DataFlavor] = xs.flatMap(_.getTransferDataFlavors)(breakOut)
      def isDataFlavorSupported(_flavor: DataFlavor): Boolean = xs.exists(_.isDataFlavorSupported(_flavor))
      def getTransferData(_flavor: DataFlavor): AnyRef = {
        val peer = xs.find(_.isDataFlavorSupported(_flavor)).getOrElse(throw new UnsupportedFlavorException(_flavor))
        peer.getTransferData(_flavor)
      }
    }
  }
}