How do I manipulate a tree of immutable objects?
- by Frederik
I'm building an entire application out of immutable objects so that multi-threading and undo become easier to implement. I'm using the Google Collections Library which provides immutable versions of Map, List, and Set.
My application model looks like a tree:
Scene is a top-level object that contains a reference to a root Node.
Each Node can contain child Nodes and Ports.
An object graph might look like this:
Scene
|
+-- Node
|
+-- Node
|
+- Port
+-- Node
|
+- Port
+- Port
If all of these objects are immutable, controlled by a top-level SceneController object:
What is the best way to construct this hierarchy?
How would I replace an object that is arbitrarily deep in the object tree?
Is there a way to support back-links, e.g. a Node having a "parent" attribute?
