package net.tomp2p.p2p;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.NavigableSet;
import java.util.Random;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.atomic.AtomicReferenceArray;
import net.tomp2p.futures.BaseFuture;
import net.tomp2p.futures.FutureResponse;
import net.tomp2p.futures.FutureRouting;
import net.tomp2p.p2p.builder.RoutingBuilder;
import net.tomp2p.peers.Number160;
import net.tomp2p.peers.PeerAddress;
import net.tomp2p.peers.PeerFilter;
import net.tomp2p.rpc.DigestInfo;
import net.tomp2p.utils.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The routing mechanism. Since this is called from Netty handlers, we don't have any visibility issues. If you want to
* use an execution handler, then it must be an OrderedMemoryAwareThreadPoolExecutor.
*
* http://stackoverflow.com/questions/8304309/keeping-state-in-a-netty-channelhandler
*
* @author Thomas Bocek
*
*/
public class RoutingMechanism {
private static final Logger LOG = LoggerFactory.getLogger(RoutingMechanism.class);
private final AtomicReferenceArray<FutureResponse> futureResponses;
private final FutureRouting futureRoutingResponse;
private final Collection<PeerFilter> peerFilters;
private NavigableSet<PeerAddress> queueToAsk;
private SortedSet<PeerAddress> alreadyAsked;
private SortedMap<PeerAddress, DigestInfo> directHits;
private NavigableSet<PeerAddress> potentialHits;
private int nrNoNewInfo = 0;
private int nrFailures = 0;
private int nrSuccess = 0;
private int maxDirectHits;
private int maxNoNewInfo;
private int maxFailures;
private int maxSucess;
private boolean stopCreatingNewFutures;
/**
* Creates the routing mechanism. Make sure to set the max* fields.
*
* @param futureResponses
* The current future responeses that are running
* @param futureRoutingResponse
* The reponse future from this routing request
*/
public RoutingMechanism(final AtomicReferenceArray<FutureResponse> futureResponses,
final FutureRouting futureRoutingResponse, final Collection<PeerFilter> peerFilters) {
this.futureResponses = futureResponses;
this.futureRoutingResponse = futureRoutingResponse;
this.peerFilters = peerFilters;
}
public FutureRouting futureRoutingResponse() {
return futureRoutingResponse;
}
/**
* @return The number of parallel requests. The number is determined by the length of the future response array
*/
public int parallel() {
return futureResponses.length();
}
/**
* @return True if we should stop creating more futures, false otherwise
*/
public boolean isStopCreatingNewFutures() {
return stopCreatingNewFutures;
}
/**
* @param i
* The number of the future response to get
* @return The future response at position i
*/
public FutureResponse futureResponse(final int i) {
return futureResponses.get(i);
}
/**
* @param i
* The number of the future response to get and set
* @param futureResponse
* The future response to set
* @return The old future response
*/
public FutureResponse futureResponse(final int i, final FutureResponse futureResponse) {
return futureResponses.getAndSet(i, futureResponse);
}
/**
* @param queueToAsk
* The queue that contains the peers that will be queried in the future
* @return This class
*/
public RoutingMechanism queueToAsk(final NavigableSet<PeerAddress> queueToAsk) {
this.queueToAsk = queueToAsk;
return this;
}
/**
* @return The queue that contains the peers that will be queried in the future
*/
public NavigableSet<PeerAddress> queueToAsk() {
synchronized (this) {
return queueToAsk;
}
}
/**
* @param alreadyAsked
* The peer we have already queried, we need to store them to not ask the same peers again
* @return This class
*/
public RoutingMechanism alreadyAsked(final SortedSet<PeerAddress> alreadyAsked) {
this.alreadyAsked = alreadyAsked;
return this;
}
/**
* @return The peer we have already queried, we need to store them to not ask the same peers again
*/
public SortedSet<PeerAddress> alreadyAsked() {
synchronized (this) {
return alreadyAsked;
}
}
/**
* @param potentialHits
* The potential hits are those reported by other peers that we did not check if they contain certain
* data.
* @return This class
*/
public RoutingMechanism potentialHits(final NavigableSet<PeerAddress> potentialHits) {
this.potentialHits = potentialHits;
return this;
}
/**
* @return The potential hits are those reported by other peers that we did not check if they contain certain data.
*/
public NavigableSet<PeerAddress> potentialHits() {
synchronized (this) {
return potentialHits;
}
}
/**
* @param directHits
* The peers that have certain data stored on it
* @return This class
*/
public RoutingMechanism directHits(final SortedMap<PeerAddress, DigestInfo> directHits) {
this.directHits = directHits;
return this;
}
/**
* @return The peers that have certain data stored on it
*/
public SortedMap<PeerAddress, DigestInfo> directHits() {
return directHits;
}
public int getMaxDirectHits() {
return maxDirectHits;
}
public void maxDirectHits(int maxDirectHits) {
this.maxDirectHits = maxDirectHits;
}
public int maxNoNewInfo() {
return maxNoNewInfo;
}
public void maxNoNewInfo(int maxNoNewInfo) {
this.maxNoNewInfo = maxNoNewInfo;
}
public int maxFailures() {
return maxFailures;
}
public void maxFailures(int maxFailures) {
this.maxFailures = maxFailures;
}
public int maxSucess() {
return maxSucess;
}
public void maxSucess(int maxSucess) {
this.maxSucess = maxSucess;
}
public PeerAddress pollFirstInQueueToAsk() {
synchronized (this) {
return queueToAsk.pollFirst();
}
}
public PeerAddress pollRandomInQueueToAsk(Random rnd) {
synchronized (this) {
return Utils.pollRandom(queueToAsk(), rnd);
}
}
public void addToAlreadyAsked(PeerAddress next) {
synchronized (this) {
alreadyAsked.add(next);
}
}
public void neighbors(RoutingBuilder builder) {
synchronized (this) {
futureRoutingResponse.neighbors(directHits, potentialHits, alreadyAsked,
builder.isBootstrap(), builder.isRoutingToOthers());
}
}
/**
* Cancel the future that causes the underlying futures to cancel as well.
*/
public void cancel() {
int len = futureResponses.length();
for (int i = 0; i < len; i++) {
BaseFuture baseFuture = futureResponses.get(i);
if (baseFuture != null) {
baseFuture.cancel();
}
}
}
public AtomicReferenceArray<FutureResponse> futureResponses() {
return futureResponses;
}
public void addPotentialHits(PeerAddress remotePeer) {
synchronized (this) {
potentialHits.add(remotePeer);
}
}
public void stopCreatingNewFutures(boolean stopCreatingNewFutures) {
this.stopCreatingNewFutures = stopCreatingNewFutures;
}
public boolean evaluateFailed() {
return (++nrFailures) > maxFailures();
}
public boolean evaluateSuccess(PeerAddress remotePeer, DigestInfo digestBean,
Collection<PeerAddress> newNeighbors, boolean last, Number160 locationkey) {
boolean finished;
synchronized (this) {
filterPeers(newNeighbors, alreadyAsked, queueToAsk, locationkey);
if (evaluateDirectHits(remotePeer, directHits, digestBean, getMaxDirectHits())) {
// stop immediately
LOG.debug("we have enough direct hits {}", directHits);
finished = true;
stopCreatingNewFutures = true;
} else if ((++nrSuccess) > maxSucess()) {
// wait until pending futures are finished
LOG.debug("we have reached max success {}", nrSuccess);
finished = last;
stopCreatingNewFutures = true;
} else if (evaluateInformation(newNeighbors, queueToAsk, alreadyAsked, maxNoNewInfo())) {
// wait until pending futures are finished
LOG.debug("we have no new information for the {} time", maxNoNewInfo());
finished = last;
stopCreatingNewFutures = true;
} else {
// continue
finished = false;
stopCreatingNewFutures = false;
}
}
return finished;
}
private void filterPeers(Collection<PeerAddress> newNeighbors, SortedSet<PeerAddress> alreadyAsked,
NavigableSet<PeerAddress> queueToAsk, Number160 locationkey) {
if (peerFilters == null || peerFilters.size() == 0) {
return;
}
Collection<PeerAddress> all = new ArrayList<PeerAddress>();
all.addAll(alreadyAsked);
all.addAll(queueToAsk);
for (Iterator<PeerAddress> iterator = newNeighbors.iterator(); iterator.hasNext();) {
PeerAddress newNeighbor = iterator.next();
for (PeerFilter peerFilter : peerFilters) {
if (peerFilter.reject(newNeighbor, all, locationkey)) {
iterator.remove();
}
}
}
}
/**
* For get requests we can finish earlier if we found the data we were looking for. This checks if we reached the
* end of our search.
*
* @param remotePeer
* The remote peer that gave us thi digest information
* @param directHits
* The result map that will store how many peers reported that data is there
* @param digestBean
* The digest information coming from the remote peer
* @param maxDirectHits
* The max. number of direct hits, e.g. finding the value we were looking for before we can stop.
* @return True if we can stop, false, if we should continue.
*/
static boolean evaluateDirectHits(final PeerAddress remotePeer,
final Map<PeerAddress, DigestInfo> directHits, final DigestInfo digestBean,
final int maxDirectHits) {
if (digestBean.size() > 0) {
directHits.put(remotePeer, digestBean);
if (directHits.size() >= maxDirectHits) {
return true;
}
}
return false;
}
/**
* Checks if we reached the end of our search.
*
* @param newNeighbors
* The new neighbors we just received
* @param queueToAsk
* The peers that are in the queue to be asked
* @param alreadyAsked
* The peers we have already asked
* @param noNewInfo
* counter how many times we did not find any peer that is closer to the target
* @param maxNoNewInfo
* The maximum number of replies from neighbors that do not give us closer peers
* @return True if we should stop, false if we should continue with the routing
*/
boolean evaluateInformation(final Collection<PeerAddress> newNeighbors,
final SortedSet<PeerAddress> queueToAsk, final Set<PeerAddress> alreadyAsked,
final int maxNoNewInfo) {
boolean newInformation = merge(queueToAsk, newNeighbors, alreadyAsked);
if (newInformation) {
nrNoNewInfo = 0;
return false;
} else {
return (++nrNoNewInfo) >= maxNoNewInfo;
}
}
/**
* Updates queueToAsk with new data, returns if we found peers closer than we already know.
*
* @param queueToAsk
* The queue to get updated
* @param newPeers
* The new peers reported from remote peers. Since the remote peers do not know what we know, we need to
* filter this information.
* @param alreadyAsked
* The peers we already know.
* @return True if we added peers that are closer to the target than we already knew. Please note, it will return
* false if we add new peers that are not closer to a target.
*/
static boolean merge(final SortedSet<PeerAddress> queueToAsk, final Collection<PeerAddress> newPeers,
final Collection<PeerAddress> alreadyAsked) {
final SortedSet<PeerAddress> result = new TreeSet<PeerAddress>(queueToAsk.comparator());
Utils.difference(newPeers, result, alreadyAsked);
if (result.size() == 0) {
return false;
}
PeerAddress first = result.first();
boolean newInfo = isNew(queueToAsk, first);
queueToAsk.addAll(result);
return newInfo;
}
/**
* Checks if an item will be the highest in a sorted set.
*
* @param queueToAsk
* The sorted set to check
* @param item
* The element to check if it will be the highest in the sorted set
* @return True, if item will be the highest element.
*/
private static boolean isNew(final SortedSet<PeerAddress> queueToAsk, final PeerAddress item) {
if (queueToAsk.contains(item)) {
return false;
}
SortedSet<PeerAddress> tmp = queueToAsk.headSet(item);
return tmp.size() == 0;
}
public int nrNoNewInfo() {
return nrNoNewInfo;
}
}