Scala Swing Tree Wrapper

This is a fork of the original project by Ken Scambler which was placed in the public domain (see issue #6).

The purpose of this fork/branch, using a BSD style license, is to move to a private name space (de.sciss.swingtree) in order to make this package available on Maven Central for ad hoc use, without the danger of colliding with a possible future scala.swing package, should this ever be incorporated into the standard Scala library.

So to link to this fork:

"de.sciss" %% "swingtree" % "1.3.+"

Below are the original notes.

This project provides a Scala wrapper for Java's JTree class, and aims to be suitable for eventual inclusion in the official Scala Swing library. The design was initiated in the Scala debate forum in February 2010.

Most uses of JTree are vastly simpler -- all you need to provide is the root nodes, and a function that provides the children.

A small, fixed tree


case class Node[A](value: A, children: Node[A]*)
val menuItems = Node("Hobbies", Node("Skateboarding"), //... etc
      
new Tree[Node] {
  model = TreeModel(menuItems)(_.children)
  renderer = Tree.Renderer(_.value)
}

An XML document


val xml: scala.xml.Node = //...
new Tree(TreeModel(Seq(xml)) {_.child.filter(_.text.trim.nonEmpty)})

The file system


new Tree[File] {
  model = TreeModel(new File(".")) {f => 
    if (f.isDirectory) f.listFiles.toSeq else Seq()
  }
}

Infinitely deep structure


// All factors of 1000, and the factors' factors, etc
new Tree(TreeModel(1000) {n => 1 to n filter (n % _ == 0)})

A diverse object graph

With a custom renderer - they are a piece of cake too.


case class Customer(id: Int, title: String, firstName: String, lastName: String)
case class Product(id: String, name: String, price: Double)
case class Order(id: Int, customer: Customer, product: Product, quantity: Int)
val orders: List[Order] = //...

new Tree[Any] {
  model = TreeModel[Any](orders: _*) {
    case Order(_, cust, prod, qty) => Seq(cust, prod, "Qty" -> qty)
    case Product(id, name, price) => Seq("ID" -> id, "Name" -> name, "Price" -> ("$" + price))
    case Customer(id, _, first, last) => Seq("ID" -> id, "First name" -> first, "Last name" -> last)
    case _ => Seq.empty
  }

  renderer = Tree.Renderer({
    case Order(id, _, _, qty) => "Order #" + id + " x " + qty
    case Product(id, _, _) => "Product " + id
    case Customer(_, title, first, last) => title + " " + first + " " + last
    case (field, value) => field + ": " + value
    case x => x.toString
  })
}

Add, edit and remove nodes on an internal model, copied from the original data.


val child = Node("child")
val parent = Node("parent", child)
val root = Node("root", parent)

val tree = new Tree[Node] {
  model = InternalTreeModel(root)(_.children)
}

// Doesn't affect the original data, because the model is internally represented.
var child2 = Node("child2")
tree.model(Path(root, parent, child)) = child2
tree.model.remove(Path(root, parent, child2))
tree.model.insertUnder(Path(root, parent), child, 0)
tree.model.insertBefore(Path(root, parent, child), Node("before-child"))
tree.model.insertAfter(Path(root, parent, child), Node("after-child"))

Add, edit and remove nodes on an external model, consisting of original data.


val child = Node("child")
val parent = Node("parent", child)
val root = Node("root", parent)

val tree = new Tree[Node] {
  model = ExternalTreeModel(root)(_.children).makeUpdatableWith {
    (pathOfFile, updatedFile) => 
      pathOfFile.last.name = updatedFile.name; pathOfFile.last
  }.makeInsertableWith {
    (parentPath, fileToInsert, index) => 
      parentPath.last.insertChild(index, fileToInsert); true
  }.makeRemovableWith {
    (pathToRemove) => 
      pathToRemove.delete(); true
  }
}

// The original data will be mutated by the given functions, because the model is externally represented.
var child2 = Node("child2")
tree.model(Path(root, parent, child)) = child2
tree.model.remove(Path(root, parent, child2))
tree.model.insertUnder(Path(root, parent), child, 0)
tree.model.insertBefore(Path(root, parent, child), Node("before-child"))
tree.model.insertAfter(Path(root, parent, child), Node("after-child"))

sciss / swingtree 1.3.0