Add a new DebugTools object for debugging methods

src/main/scala/org/gerweck/scalafx/util/ScalaFXDebugTools.scala

@@ -0,0 +1,43 @@
+package org.gerweck.scalafx.util
+
+import scalafx.scene.input.Dragboard
+
+import org.log4s._
+
+/** Miscellaneous utility methods for debugging activity. */
+object ScalaFXDebugTools {
+
+  /** Print information about drag-and-drop content to the logs.
+    *
+    * This can get quite noisy if you do it on DragOver, so typically this
+    * would only be used during debugging and disabled altogether in the real
+    * product.
+    */
+  def logDragboardInfo(logger: Logger, level: LogLevel, showData: Boolean = true)(drb: Dragboard): Unit = {
+    val summary = {
+      val m =
+        Map("html"  -> drb.hasHtml,
+            "text"  -> drb.hasString,
+            "url"   -> drb.hasUrl,
+            "image" -> drb.hasImage,
+            "rtf"   -> drb.hasRtf)
+      m.map{case (k, v) => s"has${k.capitalize}: $v"}.mkString("; ")
+    }
+    var pieces: Seq[String] = Vector(summary)
+    if (showData) {
+      if (drb.hasUrl) {
+        pieces :+= s"Dragboard URL: ${drb.url}"
+      }
+      if (drb.hasHtml) {
+        pieces :+= s"Dragboard HTML: ${drb.html}"
+      }
+      if (drb.hasString) {
+        pieces :+= s"Dragboard String: ${drb.string}"
+      }
+      if (drb.hasRtf) {
+        pieces :+= s"Dragboard RTF: ${drb.rtf}"
+      }
+    }
+    logger(level)(pieces.mkString("\n"))
+  }
+}