/** Compute the change in depth as an edge is crossed from R to L */
private static int depthDelta(Label label) {
int lLoc = label.getLocation(0, Position.LEFT);
int rLoc = label.getLocation(0, Position.RIGHT);
if (lLoc == Location.INTERIOR && rLoc == Location.EXTERIOR) return 1;
else if (lLoc == Location.EXTERIOR && rLoc == Location.INTERIOR) return -1;
return 0;
}
/**
* Inserted edges are checked to see if an identical edge already exists. If so, the edge is not
* inserted, but its label is merged with the existing edge.
*/
protected void insertUniqueEdge(Edge e) {
// <FIX> MD 8 Oct 03 speed up identical edge lookup
// fast lookup
Edge existingEdge = edgeList.findEqualEdge(e);
// If an identical edge already exists, simply update its label
if (existingEdge != null) {
Label existingLabel = existingEdge.getLabel();
Label labelToMerge = e.getLabel();
// check if new edge is in reverse direction to existing edge
// if so, must flip the label before merging it
if (!existingEdge.isPointwiseEqual(e)) {
labelToMerge = new Label(e.getLabel());
labelToMerge.flip();
}
existingLabel.merge(labelToMerge);
// compute new depth delta of sum of edges
int mergeDelta = depthDelta(labelToMerge);
int existingDelta = existingEdge.getDepthDelta();
int newDelta = existingDelta + mergeDelta;
existingEdge.setDepthDelta(newDelta);
} else { // no matching existing edge was found
// add this new edge to the list of edges in this graph
// e.setName(name + edges.size());
edgeList.add(e);
e.setDepthDelta(depthDelta(e.getLabel()));
}
}