/**
* Adds the given node reference to the finger table and successor list, if appropriate. The
* reference is NOT set as predecessor, even if is closer to this node. Therefore use {@link
* #addReferenceAsPredecessor(Node)}.
*
* @param newReference Reference to be added to the local data structures.
* @throws NullPointerException If the given reference is null.
*/
final synchronized void addReference(Node newReference) {
if (newReference == null) {
NullPointerException e =
new NullPointerException("Node reference to be added must not be null!");
this.logger.error("Null pointer", e);
throw e;
}
boolean debug = this.logger.isEnabledFor(DEBUG);
// June 21, 2006. Moved here by sven to avoid failing of checkIfProxy()
if (newReference.getNodeID().equals(this.localID)) {
if (debug) {
this.logger.debug("Reference on myself was not added");
}
return;
}
// check parameters
this.checkIfProxy(newReference);
this.fingerTable.addReference(newReference);
this.successorList.addSuccessor(newReference);
if (debug) {
this.logger.debug(
"Attempted to add reference "
+ newReference.getNodeID().toString()
+ " to finger table and successor list. Whether it fit "
+ "or not depends on those data structures.");
}
}
/**
* Determines if the given reference is contained in any one data structure, ie. finger table,
* successor list, or predecessor reference.
*
* @param newReference Reference to look up.
* @throws NullPointerException If given reference is <code>null</code>.
* @return <code>true</code> if the reference is contained and <code>false</code> if not.
*/
final synchronized boolean containsReference(Node newReference) {
if (newReference == null) {
NullPointerException e = new NullPointerException("Reference to look up must not be null!");
this.logger.error("Null pointer", e);
throw e;
}
return (this.fingerTable.containsReference(newReference)
|| this.successorList.containsReference(newReference)
|| newReference.equals(this.predecessor));
}
/**
* Adds the given node reference to the finger table and successor list AND sets it as new
* predecessor reference, if appropriate. Appropriateness is given if either the former
* predecessor reference was <code>null</code> or the new reference's ID is located between the
* old predecessor ID and this node's ID. Even if not appropriate as predecessor, the reference is
* added to finger table and successor list.
*
* @param potentialPredecessor Reference which should be this node's predecessor.
* @throws NullPointerException If the given reference is <code>null</code>.
*/
void addReferenceAsPredecessor(Node potentialPredecessor) {
this.checkIfProxy(potentialPredecessor);
if (potentialPredecessor == null) {
NullPointerException e =
new NullPointerException("Reference to potential predecessor may not be null!");
this.logger.error("Null pointer", e);
throw e;
}
// if the local node did not have a predecessor reference before
// or if the potential predecessor is closer to this local node,
// replace the predecessor reference
if (this.predecessor == null
|| potentialPredecessor
.getNodeID()
.isInInterval(this.predecessor.getNodeID(), this.localID)) {
if (this.logger.isEnabledFor(INFO)) {
this.logger.info(
"Setting a new predecessor reference: New reference is "
+ potentialPredecessor
+ ", old reference was "
+ (this.predecessor == null ? "null" : this.predecessor));
}
// replace predecessor reference
this.setPredecessor(potentialPredecessor);
/*
* If a new predecessor, better than the old one has arrived, we
* have to copy the entries, that are relevant for this new
* predecessor. This has to be done by the predecessor itself, NOT
* here. 18.06.2007. sven
*/
// final Set<Entry> entries = this.entries.getEntriesInInterval(
// this.predecessor.nodeID, this.localID);
// this.localChord.getAsyncExecutor().execute(new Runnable() {
// public void run() {
// try {
// for (Entry entryToInsert : entries) {
// getPredecessor().insertEntry(entryToInsert);
// }
// } catch (CommunicationException e) {
// }
// }
// });
}
// add reference
this.addReference(potentialPredecessor);
}
/** {@inheritDoc} */
@Override
public final void leavesNetwork(Node predecessor) {
if (this.logger.isEnabledFor(INFO)) {
this.logger.info("Leaves network invoked; " + this.nodeID + ". Updating references.");
this.logger.info("New predecessor " + predecessor.getNodeID());
}
if (this.logger.isEnabledFor(DEBUG)) {
this.logger.debug("References before update: " + this.references.toString());
}
this.references.removeReference(this.references.getPredecessor());
if (this.logger.isEnabledFor(DEBUG)) {
this.logger.debug("References after update: " + this.references.toString());
}
}
/**
* Closes the connection to the given reference, if it is not kept in any data structure (ie.
* finger table, successor list, predecessor) any more.
*
* @param removedReference Node to which the connection shall be closed, if there exists no
* reference any more.
* @throws NullPointerException If given reference is null.
*/
void disconnectIfUnreferenced(Node removedReference) {
if (removedReference == null) {
NullPointerException e = new NullPointerException("Reference may not be null!");
this.logger.error("Null pointer", e);
throw e;
}
if (!this.containsReference(removedReference)) {
if (!(removedReference instanceof Proxy)) {
this.logger.error("Attempt to disconnect unused reference failed");
throw new RuntimeException("Reference should be of type Proxy");
}
this.logger.debug("Disconnecting unused reference on node " + removedReference);
removedReference.disconnect();
}
}
/**
* Sets the given reference as this node's predecessor. If the former value of this predecessor's
* node was <code>null</code> and if this reference is not used any more (eg. in finger table or
* successor list), the connection to it is closed.
*
* @param potentialPredecessor Reference on the node to be set as new predecessor; may not be null
* @throws NullPointerException If potential predecessor is null.
*/
final synchronized void setPredecessor(Node potentialPredecessor) {
if (potentialPredecessor == null) {
NullPointerException e =
new NullPointerException(
"Potential predecessor of method setPredecessor may not be " + "null!");
this.logger.error("Null pointer", e);
throw e;
}
this.checkIfProxy(potentialPredecessor);
boolean info = this.logger.isEnabledFor(INFO);
if (!(potentialPredecessor.equals(this.predecessor))) {
Node formerPredecessor = this.predecessor;
this.predecessor = potentialPredecessor;
if (formerPredecessor != null) {
this.disconnectIfUnreferenced(formerPredecessor);
/*
* The replicas, which are in the range between the old and the
* new predecessor, on the last successor of this node have to
* be removed if the successor list is full. => capacity of sl ==
* length of sl.
*/
int sLSize = this.successorList.getSize();
if (this.successorList.getCapacity() == sLSize) {
Node lastSuccessor = this.successorList.getReferences().get(sLSize - 1);
try {
lastSuccessor.removeReplicas(this.predecessor.getNodeID(), new HashSet<Entry>());
} catch (CommunicationException e) {
logger.warn("Could not remove replicas on last predecessor", e);
}
}
if (this.logger.isEnabledFor(DEBUG)) {
this.logger.debug(
"Old predecessor " + formerPredecessor + " was replaced by " + potentialPredecessor);
}
} else {
if (info) {
this.logger.info(
"Predecessor reference set to " + potentialPredecessor + "; was null before.");
}
Set<Entry> entriesToRep =
this.entries.getEntriesInInterval(this.predecessor.getNodeID(), this.localID);
List<Node> successors = this.successorList.getReferences();
for (Node successor : successors) {
try {
successor.insertReplicas(entriesToRep);
} catch (CommunicationException e) {
this.logger.warn("Damn. Could not replicate to successor " + successor.getNodeID(), e);
}
}
}
}
}
/** {@inheritDoc} */
@Override
public final RefsAndEntries notifyAndCopyEntries(Node potentialPredecessor)
throws CommunicationException {
/*
* Mutual exclusion between notify and notifyAndCopyEntries. 17.03.2008. sven.
*/
this.notifyLock.lock();
try {
// copy all entries which lie between the local node ID and the ID
// of
// the potential predecessor, including those equal to potential
// predecessor
Set<Entry> copiedEntries =
this.entries.getEntriesInInterval(this.nodeID, potentialPredecessor.getNodeID());
return new RefsAndEntries(this.notify(potentialPredecessor), copiedEntries);
} finally {
this.notifyLock.unlock();
}
}
/**
* Removes the given node reference from the finger table and the successor list. If the given
* reference is the current predecessor, the predecessor reference will be <code>null</code>
* afterwards.
*
* @param oldReference Reference to remove from ALL data structures.
* @throws NullPointerException If reference to remove is <code>null</code>.
*/
final synchronized void removeReference(Node oldReference) {
if (oldReference == null) {
NullPointerException e = new NullPointerException("Reference to remove must not be null!");
this.logger.error("Null pointer", e);
throw e;
}
this.fingerTable.removeReference(oldReference);
this.successorList.removeReference(oldReference);
if (oldReference.equals(this.getPredecessor())) {
this.predecessor = null;
}
disconnectIfUnreferenced(oldReference);
if (this.logger.isEnabledFor(DEBUG)) {
this.logger.debug(
"Attempted to remove reference "
+ oldReference
+ " from all data structures including predecessor reference.");
}
}
/**
* Determines the closest preceding node for the given ID based on finger table, successor list,
* and predecessor, but without testing the node's liveliness.
*
* @param key ID to find closest preceding node for.
* @throws NullPointerException If ID is <code>null</code>.
* @return Reference on closest preceding node.
*/
final synchronized Node getClosestPrecedingNode(ID key) {
if (key == null) {
NullPointerException e = new NullPointerException("ID may not be null!");
this.logger.error("Null pointer", e);
throw e;
}
Map<ID, Node> foundNodes = new HashMap<ID, Node>();
// determine closest preceding reference of finger table
Node closestNodeFT = this.fingerTable.getClosestPrecedingNode(key);
if (closestNodeFT != null) {
foundNodes.put(closestNodeFT.getNodeID(), closestNodeFT);
}
// determine closest preceding reference of successor list
Node closestNodeSL = this.successorList.getClosestPrecedingNode(key);
if (closestNodeSL != null) {
foundNodes.put(closestNodeSL.getNodeID(), closestNodeSL);
}
// predecessor is appropriate only if it precedes the given id
Node predecessorIfAppropriate = null;
if (this.predecessor != null && key.isInInterval(this.predecessor.getNodeID(), this.localID)) {
predecessorIfAppropriate = this.predecessor;
foundNodes.put(this.predecessor.getNodeID(), predecessor);
}
// with three references which may be null, there are eight (8) cases we
// have to enumerate...
Node closestNode = null;
List<ID> orderedIDList = new ArrayList<ID>(foundNodes.keySet());
orderedIDList.add(key);
int sizeOfList = orderedIDList.size();
// size of list must be greater than one to not only contain the key.
// if (sizeOfList > 1) {
/*
* Sort list in ascending order
*/
Collections.sort(orderedIDList);
/*
* The list item with one index lower than that of the key must be the
* id of the closest predecessor or the key.
*/
int keyIndex = orderedIDList.indexOf(key);
/*
* As all ids are located on a ring if the key is the first item in the
* list we have to select the last item as predecessor with help of this
* calculation.
*/
int index = (sizeOfList + (keyIndex - 1)) % sizeOfList;
/*
* Get the references to the node from the map of collected nodes.
*/
ID idOfclosestNode = orderedIDList.get(index);
closestNode = foundNodes.get(idOfclosestNode);
if (closestNode == null) {
throw new NullPointerException("closestNode must not be null!");
}
/*
* Following code is too complicated.
*/
// if (closestNodeFT == null) {
// if (closestNodeSL == null) {
// if (predecessorIfAppropriate == null) {
// // no reference is appropriate
// closestNode = null;
// } else {
// // only predecessor is appropriate (case should not occur,
// // but anyway...
// closestNode = predecessorIfAppropriate;
// }
// } else {
// if (predecessorIfAppropriate == null) {
// // only reference of successor list is appropriate
// closestNode = closestNodeSL;
// } else {
// // either predecessor or reference of successor list is
// // appropriate; determine one of both
// if (predecessorIfAppropriate.nodeID.isInInterval(
// closestNodeSL.nodeID, key)) {
// closestNode = predecessorIfAppropriate;
// } else {
// closestNode = closestNodeSL;
// }
// }
// }
// } else {
// if (closestNodeSL == null) {
// if (predecessorIfAppropriate == null) {
// // only reference of finger table is appropriate
// closestNode = closestNodeFT;
// } else {
// // either predecessor or reference of finger table is
// // appropriate; determine one of both
// if (predecessorIfAppropriate.nodeID.isInInterval(
// closestNodeFT.nodeID, key)) {
// closestNode = predecessorIfAppropriate;
// } else {
// closestNode = closestNodeFT;
// }
// }
// } else {
// if (predecessorIfAppropriate == null) {
// // either reference of successor list or reference of finger
// // table is appropriate; determine one of both
// if (closestNodeSL.nodeID.isInInterval(closestNodeFT.nodeID,
// key)) {
// closestNode = closestNodeSL;
// } else {
// closestNode = closestNodeFT;
// }
// } else {
// // either of the three reference is appropriate; determine
// // first one of the references of successor list and finger
// // table is more appropriate and afterwards compare with
// // predecessor
// if (closestNodeSL.nodeID.isInInterval(closestNodeFT.nodeID,
// key)) {
// if (predecessorIfAppropriate.nodeID.isInInterval(
// closestNodeSL.nodeID, key)) {
// closestNode = predecessorIfAppropriate;
// } else {
// closestNode = closestNodeSL;
// }
// } else {
// if (predecessorIfAppropriate.nodeID.isInInterval(
// closestNodeFT.nodeID, key)) {
// closestNode = predecessorIfAppropriate;
// } else {
// closestNode = closestNodeFT;
// }
// }
// }
// }
// }
if (this.logger.isEnabledFor(DEBUG)) {
this.logger.debug(
"Closest preceding node of ID "
+ key
+ " at node "
+ this.localID.toString()
+ " is "
+ closestNode.getNodeID()
+ " with closestNodeFT="
+ (closestNodeFT == null ? "null" : "" + closestNodeFT.getNodeID())
+ " and closestNodeSL="
+ (closestNodeSL == null ? "null" : "" + closestNodeSL.getNodeID())
+ " and predecessor (only if it precedes given ID)="
+ (predecessorIfAppropriate == null
? "null"
: "" + predecessorIfAppropriate.getNodeID()));
}
return closestNode;
}
// TODO: implement this function in TTP
@Override
public final void broadcast(Broadcast info) throws CommunicationException {
if (this.logger.isEnabledFor(DEBUG)) {
this.logger.debug(" Send broadcast message");
}
// System.out.println("NodeImpl: Send broadcast: " + info);
// Check transaction Number, only accept ascending Numbers
if (info.getTransaction() > this.getTransactionCount()) {
System.out.println(
"NodeImpl: Updating transaction Number from "
+ this.getTransactionCount()
+ " to "
+ info.getTransaction());
this.setTransactionCount(info.getTransaction());
} else {
System.out.println("NodeImpl: Ignoring old transaction ID " + info.getTransaction());
System.out.println("################################################################");
return;
}
// Get and sort known nodes
List<Node> fingerTable = references.getFingerTableEntries();
// make IDs in fingerTable unique
HashSet<Node> fingerSet = new HashSet<Node>(fingerTable);
// but list is better for iteration (we'll frequently need next's next)
List<Node> knownNodes = new ArrayList<Node>(fingerSet);
Collections.sort(knownNodes);
// Iterate over nodes
for (int i = 0; i < knownNodes.size(); ++i) {
Node n = knownNodes.get(i);
// Only broadcast to nodes between own ID and range
if (!n.getNodeID().isInInterval(this.getNodeID(), info.getRange())) {
System.out.println("NodeImpl: Not in range, not sending broadcast");
break;
}
// find successor of Node n (stays if we're at the last node)
ID successorID = info.getRange();
if (knownNodes.size() > i + 1) {
successorID = knownNodes.get(i + 1).getNodeID();
}
// Create broadcast object and send
Broadcast bc =
new Broadcast(
successorID,
this.getNodeID(),
info.getTarget(),
info.getTransaction(),
info.getHit());
// System.out.println("NodeImpl: Broadcasting: " + bc);
n.broadcast(bc);
}
// finally inform application
if (this.notifyCallback != null) {
this.notifyCallback.broadcast(info.getSource(), info.getTarget(), info.getHit());
}
System.out.println("################################################################");
}