Implemented a node placer using Walker's algorithm in ELK Layered

[stu241636]

No description provided.

[stu241636]

The following examples are still problematic:
Since the algorithm is fundamentally a tree-drawing algorithm, graphs which have cycles (in the undirected sense) are drawn unnaturally, as seen in the following example:

algorithm: layered
elk.direction: DOWN
nodePlacement.strategy: WALKER
nodePlacement.bk.fixedAlignment: BALANCED
cycleBreaking.strategy: MODEL_ORDER
considerModelOrder.strategy: NODES_AND_EDGES

node top
node left
node right
node bottom

edge top -> left
edge top -> right
edge left -> bottom
edge right -> bottom

Dangling nodes, which fundamentally also do not construct a tree, but which contain no cycles, are placed on top of each other:

algorithm: layered
elk.direction: DOWN
nodePlacement.strategy: WALKER
nodePlacement.bk.fixedAlignment: BALANCED
cycleBreaking.strategy: MODEL_ORDER
considerModelOrder.strategy: NODES_AND_EDGES

node n1
node n3
node n2

edge n1 -> n2
edge n3 -> n2

[soerendomroes]

If I read the message correctly, the second argument of toArray must be an LEdge[]?

ERROR] Line 130: The method toArray(Iterable<? extends T>, T[]) in the type Iterables is not applicable for the arguments (Iterable<LEdge>, Class<LEdge>)