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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.zookeeper.server.quorum;
import java.util.Collections;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.server.SessionTracker;
import org.apache.zookeeper.server.ZooKeeperServerListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A session tracker that supports upgradeable local sessions.
*/
public abstract class UpgradeableSessionTracker implements SessionTracker {
private static final Logger LOG = LoggerFactory.getLogger(UpgradeableSessionTracker.class);
private ConcurrentMap<Long, Integer> localSessionsWithTimeouts;
private ConcurrentMap<Long, Integer> upgradingSessions;
protected LocalSessionTracker localSessionTracker;
protected boolean localSessionsEnabled;
public void start() {
}
public void createLocalSessionTracker(SessionExpirer expirer, int tickTime, long id, ZooKeeperServerListener listener) {
this.localSessionsWithTimeouts = new ConcurrentHashMap<>();
this.localSessionTracker = new LocalSessionTracker(expirer, this.localSessionsWithTimeouts, tickTime, id, listener);
this.upgradingSessions = new ConcurrentHashMap<>();
}
public boolean isTrackingSession(long sessionId) {
return isLocalSession(sessionId) || isGlobalSession(sessionId);
}
public boolean isLocalSession(long sessionId) {
return localSessionTracker != null && localSessionTracker.isTrackingSession(sessionId);
}
@Override
public boolean isLocalSessionsEnabled() {
return localSessionsEnabled;
}
public boolean isUpgradingSession(long sessionId) {
return upgradingSessions != null && upgradingSessions.containsKey(sessionId);
}
public void finishedUpgrading(long sessionId) {
if (upgradingSessions != null) {
upgradingSessions.remove(sessionId);
}
}
public abstract boolean isGlobalSession(long sessionId);
/**
* Upgrades the session to a global session.
* This simply removes the session from the local tracker and marks
* it as global. It is up to the caller to actually
* queue up a transaction for the session.
*
* @param sessionId
* @return session timeout (-1 if not a local session)
*/
public int upgradeSession(long sessionId) {
if (localSessionsWithTimeouts == null) {
return -1;
}
// We won't race another upgrade attempt because only one thread
// will get the timeout from the map
Integer timeout = localSessionsWithTimeouts.remove(sessionId);
if (timeout != null) {
LOG.info("Upgrading session 0x{}", Long.toHexString(sessionId));
// Track global session, which will add to global session tracker
// on leader and do nothing on learner. Need to start track global
// session in leader now to update the session expire between
// LeaderRequestProcessor and PrepRequestProcessor.
trackSession(sessionId, timeout);
// Track ongoing upgrading sessions, learner will use it to find
// other sessions it has which are not in local and global sessions
upgradingSessions.put(sessionId, timeout);
localSessionTracker.removeSession(sessionId);
return timeout;
}
return -1;
}
protected void removeLocalSession(long sessionId) {
if (localSessionTracker == null) {
return;
}
localSessionTracker.removeSession(sessionId);
}
public void checkGlobalSession(long sessionId, Object owner)
throws KeeperException.SessionExpiredException, KeeperException.SessionMovedException {
throw new UnsupportedOperationException();
}
public long getLocalSessionCount() {
if (localSessionsWithTimeouts == null) {
return 0;
}
return localSessionsWithTimeouts.size();
}
public Set<Long> localSessions() {
return (localSessionTracker == null) ? Collections.<Long>emptySet()
: localSessionTracker.localSessions();
}
}
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