/**
* Creates the bag for the peers. This peer knows a lot about close peers and the further away the
* peers are, the less known they are. Distance is measured with XOR of the peer ID. The distance
* of peer with ID 0x12 and peer with Id 0x28 is 0x3a.
*
* @param self The peer ID of this peer
* @param configuration Configuration settings for this map
*/
public PeerMap(
final Number160 self,
int bagSize,
int cacheTimeoutMillis,
int maxNrBeforeExclude,
int[] waitingTimeBetweenNodeMaintenenceSeconds,
int cachSize,
MapAcceptHandler mapHandler) {
if (self == null || self.isZero())
throw new IllegalArgumentException("Zero or null are not a valid IDs");
this.self = self;
this.peerMapStat = new PeerMapStat();
// The original Kademlia suggests 20, butwe can go much lower, as we
// dont have a fixed limit for a bag. The bagSize is a suggestion and if
// maxpeers has not been reached, the peer is added even though it
// exceeds the bag limit.
this.bagSize = bagSize;
this.maxPeers = bagSize * Number160.BITS;
// The time that a removed peer will be in the cache in milliseconds.
this.cacheTimeout = cacheTimeoutMillis;
this.maxFail = maxNrBeforeExclude;
this.maintenanceTimeoutsSeconds = waitingTimeBetweenNodeMaintenenceSeconds;
// The size of the cache of removed peers
this.peerOfflineLogs = new CacheMap<PeerAddress, Log>(cachSize, false);
this.mapHandler = mapHandler;
List<Map<Number160, PeerAddress>> tmp = new ArrayList<Map<Number160, PeerAddress>>();
for (int i = 0; i < Number160.BITS; i++) {
// I made some experiments here and concurrent sets are not
// necessary, as we divide similar to segments aNonBlockingHashSets
// in a
// concurrent map. In a full network, we have 160 segments, for
// smaller we see around 3-4 segments, growing with the number of
// peers. bags closer to 0 will see more read than write, and bags
// closer to 160 will see more writes than reads.
tmp.add(
Collections.<Number160, PeerAddress>synchronizedMap(
new HashMap<Number160, PeerAddress>()));
}
this.peerMap = Collections.unmodifiableList(tmp);
this.statistics = new Statistics(peerMap, self, maxPeers, bagSize);
}
/**
* The distance metric is the XOR metric.
*
* @param id1 The first id
* @param id2 The second id
* @return The distance
*/
static Number160 distance(Number160 id1, Number160 id2) {
return id1.xor(id2);
}
