private boolean isInDistanceInternal(
int distance, NetworkNode from, NetworkNode to, TwoNetworkNodes cachePairKey) {
if (from.equals(to)) return true;
if (distance == 0) return false;
if (SimpleNetwork.areNodesConnecting(from, to)) return true;
// Breadth-first search of the network
Set<NetworkNode> visitedNodes = Sets.newHashSet();
visitedNodes.add(from);
Set<NetworkNode> networkingNodesToTest = Sets.newHashSet();
listConnectedNotVisitedNetworkingNodes(visitedNodes, from, networkingNodesToTest);
int distanceSearched = 1;
while (distanceSearched < distance) {
distanceSearched++;
for (NetworkNode nodeToTest : networkingNodesToTest) {
if (SimpleNetwork.areNodesConnecting(nodeToTest, to)) {
distanceCache.put(cachePairKey, distanceSearched);
return true;
}
visitedNodes.add(nodeToTest);
}
Set<NetworkNode> nextNetworkingNodesToTest = Sets.newHashSet();
for (NetworkNode nodeToTest : networkingNodesToTest)
listConnectedNotVisitedNetworkingNodes(visitedNodes, nodeToTest, nextNetworkingNodesToTest);
networkingNodesToTest = nextNetworkingNodesToTest;
}
return false;
}
@Override
public int getDistance(NetworkNode from, NetworkNode to) {
TwoNetworkNodes nodePair = new TwoNetworkNodes(from, to);
final Integer cachedDistance = distanceCache.get(nodePair);
if (cachedDistance != null) return cachedDistance;
if ((!hasNetworkingNode(from) && !hasLeafNode(from))
|| (!hasNetworkingNode(to) && !hasLeafNode(to)))
throw new IllegalArgumentException("Cannot test nodes not in network");
if (from.equals(to)) return 0;
if (SimpleNetwork.areNodesConnecting(from, to)) return 1;
// Breadth-first search of the network
Set<NetworkNode> visitedNodes = Sets.newHashSet();
visitedNodes.add(from);
Set<NetworkNode> networkingNodesToTest = Sets.newHashSet();
listConnectedNotVisitedNetworkingNodes(visitedNodes, from, networkingNodesToTest);
int distanceSearched = 1;
while (networkingNodesToTest.size() > 0) {
distanceSearched++;
for (NetworkNode nodeToTest : networkingNodesToTest) {
if (SimpleNetwork.areNodesConnecting(nodeToTest, to)) {
distanceCache.put(new TwoNetworkNodes(from, to), distanceSearched);
return distanceSearched;
}
visitedNodes.add(nodeToTest);
}
Set<NetworkNode> nextNetworkingNodesToTest = Sets.newHashSet();
for (NetworkNode nodeToTest : networkingNodesToTest)
listConnectedNotVisitedNetworkingNodes(visitedNodes, nodeToTest, nextNetworkingNodesToTest);
networkingNodesToTest = nextNetworkingNodesToTest;
}
return -1;
}