DataTree
/**
key : sessionId value: 该sessionId创建的临时节点列表
* This hashtable lists the paths of the ephemeral nodes of a session.
*/
private final Map<Long, HashSet<String>> ephemerals = new ConcurrentHashMap<Long, HashSet<String>>();
createNode
public void createNode(final String path, byte data[], List<ACL> acl,
long ephemeralOwner, int parentCVersion, long zxid, long time, Stat outputStat)
throws KeeperException.NoNodeException,
KeeperException.NodeExistsException {
int lastSlash = path.lastIndexOf('/');
String parentName = path.substring(0, lastSlash);
String childName = path.substring(lastSlash + 1);
StatPersisted stat = new StatPersisted();
stat.setCtime(time);
stat.setMtime(time);
stat.setCzxid(zxid);
stat.setMzxid(zxid);
stat.setPzxid(zxid);
stat.setVersion(0);
stat.setAversion(0);
stat.setEphemeralOwner(ephemeralOwner);
DataNode parent = nodes.get(parentName); // 获取父节点
if (parent == null) { // 获取不到会报错
throw new KeeperException.NoNodeException(); // 报错: Node does not exist
}
synchronized (parent) {
Set<String> children = parent.getChildren();
if (children.contains(childName)) { // 已经存在子节点
throw new KeeperException.NodeExistsException(); // 存在报错: Node already exists
}
if (parentCVersion == -1) {
parentCVersion = parent.stat.getCversion();
parentCVersion++;
}
parent.stat.setCversion(parentCVersion);
parent.stat.setPzxid(zxid);
Long longval = aclCache.convertAcls(acl);
DataNode child = new DataNode(data, longval, stat); // 创建1个子节点
parent.addChild(childName); // 添加到父节点队列上
nodes.put(path, child); // 把该节点放到nodes上 不管是否临时节点 都放进去
EphemeralType ephemeralType = EphemeralType.get(ephemeralOwner);
if (ephemeralType == EphemeralType.CONTAINER) {
containers.add(path);
} else if (ephemeralType == EphemeralType.TTL) {
ttls.add(path);
} else if (ephemeralOwner != 0) { // 关注临时节点 *****
HashSet<String> list = ephemerals.get(ephemeralOwner);
if (list == null) {
list = new HashSet<String>();
// key:sessionId value: 该会话创建的临时节点列表
ephemerals.put(ephemeralOwner, list);
}
synchronized (list) {
list.add(path); // todo 添加到临时节点列表
}
}
if (outputStat != null) {
child.copyStat(outputStat);
}
}
// now check if its one of the zookeeper node child
if (parentName.startsWith(quotaZookeeper)) { //父节点是/zookeeper/quota
// now check if its the limit node
if (Quotas.limitNode.equals(childName)) {
// this is the limit node
// get the parent and add it to the trie
pTrie.addPath(parentName.substring(quotaZookeeper.length()));
}
if (Quotas.statNode.equals(childName)) {
updateQuotaForPath(parentName
.substring(quotaZookeeper.length()));
}
}
// also check to update the quotas for this node
String lastPrefix = getMaxPrefixWithQuota(path);
if(lastPrefix != null) {
// ok we have some match and need to update
updateCount(lastPrefix, 1);
updateBytes(lastPrefix, data == null ? 0 : data.length);
}
dataWatches.triggerWatch(path, Event.EventType.NodeCreated);
childWatches.triggerWatch(parentName.equals("") ? "/" : parentName,
Event.EventType.NodeChildrenChanged);
}
killSession
正常断开，或非正常连接断开的时候，会调用killSession，这里把该会话创建的临时节点都删除
void killSession(long session, long zxid) {
// the list is already removed from the ephemerals
// so we do not have to worry about synchronizing on
// the list. This is only called from FinalRequestProcessor
// so there is no need for synchronization. The list is not
// changed here. Only create and delete change the list which
// are again called from FinalRequestProcessor in sequence.
HashSet<String> list = ephemerals.remove(session); // todo 临时节点删除 临时节点不能有子节点 1个session有多个临时节点
if (list != null) {
for (String path : list) {
try {
deleteNode(path, zxid); // 删除节点
} catch (NoNodeException e) {
}
}
}
