/**
* Wraps all {@link NodeLayout} objects into an internal presentation {@link NodeWrapper} and
* inserts dummy wrappers into the layers between an object and their predecessing nodes if
* necessary. Finally, all nodes are chained over immediate adjacent layers down to their
* predecessors. This is necessary to apply the final step of the Sugiyama algorithm to refine the
* node position within a layer.
*
* @param list : List of all {@link NodeLayout} objects within the current layer
*/
private void addLayer(List<NodeLayout> list) {
ArrayList<NodeWrapper> layer = new ArrayList<NodeWrapper>(list.size());
for (NodeLayout node : list) {
// wrap each NodeLayout with the internal data object and provide a
// corresponding mapping
NodeWrapper nw = new NodeWrapper(node, layers.size());
map.put(node, nw);
layer.add(nw);
// insert dummy nodes if the adjacent layer does not contain the
// predecessor
for (NodeLayout node_predecessor : node.getPredecessingNodes()) { // for
// all
// predecessors
NodeWrapper nw_predecessor = map.get(node_predecessor);
if (nw_predecessor != null) {
for (int level = nw_predecessor.layer + 1; level < nw.layer; level++) {
// add "virtual" wrappers (dummies) to the layers in
// between
// virtual wrappers are in fact parts of a double linked
// list
NodeWrapper nw_dummy = new NodeWrapper(level);
nw_dummy.addPredecessor(nw_predecessor);
nw_predecessor.addSuccessor(nw_dummy);
nw_predecessor = nw_dummy;
layers.get(level).add(nw_dummy);
}
nw.addPredecessor(nw_predecessor);
nw_predecessor.addSuccessor(nw);
}
}
}
layers.add(layer);
updateIndex(layer);
}
public List<List<NodeWrapper>> calculateLayers(
List<NodeLayout> nodes, Map<NodeLayout, Integer> assignedNodes) {
// TODO Auto-generated method stub
map.clear();
List<NodeLayout> predecessors = findRoots(nodes);
nodes.removeAll(predecessors); // nodes now contains only nodes that are
// no roots
addLayer(predecessors);
for (int level = 1; nodes.isEmpty() == false; level++) {
if (level > MAX_LAYERS)
throw new RuntimeException(
"Graphical tree exceeds maximum depth of "
+ MAX_LAYERS
+ "! (Graph not directed? Cycles?)");
List<NodeLayout> layer = new ArrayList<NodeLayout>();
for (NodeLayout item : nodes) {
if (predecessors.containsAll(Arrays.asList(item.getPredecessingNodes()))) layer.add(item);
}
if (layer.size() == 0) layer.add(nodes.get(0));
nodes.removeAll(layer);
predecessors.addAll(layer);
addLayer(layer);
}
return layers;
}
private static List<NodeLayout> findRoots(List<NodeLayout> list) {
List<NodeLayout> roots = new ArrayList<NodeLayout>();
for (NodeLayout iter : list) { // no predecessors means: this is a root,
// add it to list
if (iter.getPredecessingNodes().length == 0) roots.add(iter);
}
return (roots);
}
