Is there a Directed Acyclic Graph (DAG) data type in Java, and should I use it?

Question

I am modeling a power subsystem in Java. A simple SQLite database contains a set of Line Replaceable Units (LRUs) and the connections between them. I am writing a Power Mode

Answer 1

FWIW if someone wants a standard-libraries only solution, A map of sets or a map of other collections might do the job too, although not as well.

Answer 2

For this particular problem. I've decided to use a LinkedListMultimap from Guava.

Answer 3

As you can see if regarding the "related" questions, similar questions were already asked. And no, Java does not have a general-purpose graph/tree/DAG data type (if we don't count Swing's TreeModel).

Make your own one.

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Here is an example (readonly) interface:

interface Node<N extends Node<N,E>, E extends Edge<N,E>> {
    public Set<E> outgoingEdges();
    public Set<E> ingoingEdges();
}

interface Edge<N extends Node<N,E>, E extends Edge<N,E>> {
    public E source();
    public E sink();
}

You would then have

interface LRU implements Node<LRU, Line> { ... }
interface Line implements Edge<LRU, Line> { ... }

(or classes instead).

Answer 4

I don't know if it can help but take a look at JGraphT.