LocalZooKeeperCache.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * Licensed 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 com.yahoo.pulsar.zookeeper;

import java.util.concurrent.ScheduledExecutorService;

import org.apache.bookkeeper.util.OrderedSafeExecutor;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Per ZK client ZooKeeper cache supporting ZNode data and children list caches. A cache entry is identified, accessed
 * and invalidated by the ZNode path. For the data cache, ZNode data parsing is done at request time with the given
 * {@link Deserializer} argument.
 *
 * @param <T>
 */
public class LocalZooKeeperCache extends ZooKeeperCache {

    private static final Logger LOG = LoggerFactory.getLogger(LocalZooKeeperCache.class);

    public LocalZooKeeperCache(final ZooKeeper zk, final OrderedSafeExecutor executor,
            ScheduledExecutorService scheduledExecutor) {
        super(zk, executor, scheduledExecutor);
    }

    @Override
    public <T> void process(WatchedEvent event, final CacheUpdater<T> updater) {
        if (LOG.isDebugEnabled()) {
            LOG.debug("Got Local ZooKeeper WatchedEvent: EventType: {}, KeeperState: {}, Path: {}", event.getType(),
                    event.getState(), event.getPath());
        }
        if (event.getType() == Event.EventType.None) {
            switch (event.getState()) {
            case Expired:
                // in case of expired, the zkSession is no longer good
                LOG.warn("Lost connection from local ZK. Invalidating the whole cache.");
                dataCache.synchronous().invalidateAll();
                childrenCache.invalidateAll();
                return;
            default:
                break;
            }
        }
        super.process(event, updater);
    }
}