Persistent data structures in Java

Question

Does anyone know a library or some at least some research on creating and using persistent data structures in Java? I don\'t refer to persistence as long term storage but persis

Answer 1

Have a look at Functional Java. Currently provided persistent datastructures include:

• Singly-linked list (fj.data.List)
• Lazy singly-linked list (fj.data.Stream)
• Nonempty list (fj.data.NonEmptyList)
• Optional value (a container of length 0 or 1) (fj.data.Option)
• Set (fj.data.Set)
• Multi-way tree (a.k.a. rose tree) (fj.data.Tree)
• Immutable map (fj.data.TreeMap)
• Products (tuples) of arity 1-8 (fj.P1..P8)
• Vectors of arity 2-8 (fj.data.vector.V2..V8)
• Pointed list (fj.data.Zipper)
• Pointed tree (fj.data.TreeZipper)
• Type-safe, generic heterogeneous list (fj.data.hlist.HList)
• Immutable arrays (fj.data.Array)
• Disjoint union datatype (fj.data.Either)

A number of usage examples are provided with the binary distribution. The source is available under a BSD license from Google Code.