/**
* Breadth first traversal of the topology DAG
*
* @param topologies
* @param td
* @param spouts
* @return A partial ordering of components
*/
private Queue<Component> bfs(Topologies topologies, TopologyDetails td, List<Component> spouts) {
// Since queue is a interface
Queue<Component> ordered__Component_list = new LinkedList<Component>();
HashMap<String, Component> visited = new HashMap<String, Component>();
/* start from each spout that is not visited, each does a breadth-first traverse */
for (Component spout : spouts) {
if (!visited.containsKey(spout.id)) {
Queue<Component> queue = new LinkedList<Component>();
queue.offer(spout);
while (!queue.isEmpty()) {
Component comp = queue.poll();
visited.put(comp.id, comp);
ordered__Component_list.add(comp);
List<String> neighbors = new ArrayList<String>();
neighbors.addAll(comp.children);
neighbors.addAll(comp.parents);
for (String nbID : neighbors) {
if (!visited.containsKey(nbID)) {
Component child = topologies.getAllComponents().get(td.getId()).get(nbID);
queue.offer(child);
}
}
}
}
}
return ordered__Component_list;
}
private List<Component> getSpouts(Topologies topologies, TopologyDetails td) {
List<Component> spouts = new ArrayList<Component>();
for (Component c : topologies.getAllComponents().get(td.getId()).values()) {
if (c.type == Component.ComponentType.SPOUT) {
spouts.add(c);
}
}
return spouts;
}