org.apache.accumulo.server.conf.ZooConfigurationFactory.java Source code

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Here is the source code for org.apache.accumulo.server.conf.ZooConfigurationFactory.java

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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.accumulo.server.conf;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import org.apache.accumulo.core.client.Instance;
import org.apache.accumulo.core.conf.AccumuloConfiguration;
import org.apache.accumulo.core.conf.Property;
import org.apache.accumulo.core.zookeeper.ZooUtil;
import org.apache.accumulo.fate.zookeeper.ZooCache;
import org.apache.accumulo.fate.zookeeper.ZooCacheFactory;
import org.apache.accumulo.server.Accumulo;
import org.apache.accumulo.server.fs.VolumeManager;
import org.apache.accumulo.server.fs.VolumeManagerImpl;
import org.apache.hadoop.fs.Path;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;

/**
 * A factory for {@link ZooConfiguration} objects.
 */
class ZooConfigurationFactory {
    private static final Map<String, ZooConfiguration> instances = new HashMap<>();

    /**
     * Gets a configuration object for the given instance with the given parent. Repeated calls will
     * return the same object.
     *
     * @param inst
     *          instance; if null, instance is determined from HDFS
     * @param zcf
     *          {@link ZooCacheFactory} for building {@link ZooCache} to contact ZooKeeper (required)
     * @param parent
     *          parent configuration (required)
     * @return configuration
     */
    ZooConfiguration getInstance(Instance inst, ZooCacheFactory zcf, AccumuloConfiguration parent) {
        String instanceId;
        if (inst == null) {
            // InstanceID should be the same across all volumes, so just choose one
            VolumeManager fs;
            try {
                fs = VolumeManagerImpl.get();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            Path instanceIdPath = Accumulo.getAccumuloInstanceIdPath(fs);
            instanceId = ZooUtil.getInstanceIDFromHdfs(instanceIdPath, parent);
        } else {
            instanceId = inst.getInstanceID();
        }

        ZooConfiguration config;
        synchronized (instances) {
            config = instances.get(instanceId);
            if (config == null) {
                ZooCache propCache;

                // The purpose of this watcher is a hack. It forces the creation on a new zoocache instead
                // of using a shared one. This was done so that the zoocache
                // would update less, causing the configuration update count to changes less.
                Watcher watcher = new Watcher() {
                    @Override
                    public void process(WatchedEvent arg0) {
                    }
                };
                if (inst == null) {
                    propCache = zcf.getZooCache(parent.get(Property.INSTANCE_ZK_HOST),
                            (int) parent.getTimeInMillis(Property.INSTANCE_ZK_TIMEOUT), watcher);
                } else {
                    propCache = zcf.getZooCache(inst.getZooKeepers(), inst.getZooKeepersSessionTimeOut(), watcher);
                }
                config = new ZooConfiguration(instanceId, propCache, parent);
                instances.put(instanceId, config);
            }
        }
        return config;
    }

    /**
     * Gets a configuration object for the given instance with the given parent. Repeated calls will
     * return the same object.
     *
     * @param inst
     *          instance; if null, instance is determined from HDFS
     * @param parent
     *          parent configuration (required)
     * @return configuration
     */
    public ZooConfiguration getInstance(Instance inst, AccumuloConfiguration parent) {
        return getInstance(inst, new ZooCacheFactory(), parent);
    }
}