private void handleSourcePathSet(int source, int dst, ArrayList<Walk> pathSet) {
        HashMap<String, Integer> pathDist = new HashMap<String, Integer>();
        for(Walk w : pathSet) {
            String pathType = getPathType(w);
            if (pathDist.containsKey(pathType)) {
                pathDist.put(pathType, pathDist.get(pathType) + 1);
            } else {
                pathDist.put(pathType, 1);
            }
        }

        try {
            // Write the distribution out to a file. You probably want to replace this.
            for(Map.Entry<String, Integer> pathCount : pathDist.entrySet()) {
                output.write(source + "-" + dst +"," + pathCount.getKey() + "," + pathCount.getValue() + "\n");
            }
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }