org.apache.hadoop.hbase.client.ZooKeeperRegistry.java Source code

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Here is the source code for org.apache.hadoop.hbase.client.ZooKeeperRegistry.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.hadoop.hbase.client;

import java.io.IOException;
import java.io.InterruptedIOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.zookeeper.MetaRegionTracker;
import org.apache.hadoop.hbase.zookeeper.ZKClusterId;
import org.apache.hadoop.hbase.zookeeper.ZKTableStateClientSideReader;
import org.apache.hadoop.hbase.zookeeper.ZKUtil;
import org.apache.zookeeper.KeeperException;

/**
 * A cluster registry that stores to zookeeper.
 */
class ZooKeeperRegistry implements Registry {
    static final Log LOG = LogFactory.getLog(ZooKeeperRegistry.class);
    // Needs an instance of hci to function.  Set after construct this instance.
    ConnectionManager.HConnectionImplementation hci;

    @Override
    public void init(HConnection connection) {
        if (!(connection instanceof ConnectionManager.HConnectionImplementation)) {
            throw new RuntimeException("This registry depends on HConnectionImplementation");
        }
        this.hci = (ConnectionManager.HConnectionImplementation) connection;
    }

    @Override
    public HRegionLocation getMetaRegionLocation() throws IOException {
        ZooKeeperKeepAliveConnection zkw = hci.getKeepAliveZooKeeperWatcher();

        try {
            if (LOG.isTraceEnabled()) {
                LOG.trace("Looking up meta region location in ZK," + " connection=" + this);
            }
            ServerName servername = MetaRegionTracker.blockUntilAvailable(zkw, hci.rpcTimeout);
            if (LOG.isTraceEnabled()) {
                LOG.trace("Looked up meta region location, connection=" + this + "; serverName="
                        + ((servername == null) ? "null" : servername));
            }
            if (servername == null)
                return null;
            return new HRegionLocation(HRegionInfo.FIRST_META_REGIONINFO, servername, 0);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            return null;
        } finally {
            zkw.close();
        }
    }

    private String clusterId = null;

    @Override
    public String getClusterId() {
        if (this.clusterId != null)
            return this.clusterId;
        // No synchronized here, worse case we will retrieve it twice, that's
        //  not an issue.
        ZooKeeperKeepAliveConnection zkw = null;
        try {
            zkw = hci.getKeepAliveZooKeeperWatcher();
            this.clusterId = ZKClusterId.readClusterIdZNode(zkw);
            if (this.clusterId == null) {
                LOG.info("ClusterId read in ZooKeeper is null");
            }
        } catch (KeeperException e) {
            LOG.warn("Can't retrieve clusterId from Zookeeper", e);
        } catch (IOException e) {
            LOG.warn("Can't retrieve clusterId from Zookeeper", e);
        } finally {
            if (zkw != null)
                zkw.close();
        }
        return this.clusterId;
    }

    @Override
    public boolean isTableOnlineState(TableName tableName, boolean enabled) throws IOException {
        ZooKeeperKeepAliveConnection zkw = hci.getKeepAliveZooKeeperWatcher();
        try {
            if (enabled) {
                return ZKTableStateClientSideReader.isEnabledTable(zkw, tableName);
            }
            return ZKTableStateClientSideReader.isDisabledTable(zkw, tableName);
        } catch (KeeperException e) {
            throw new IOException("Enable/Disable failed", e);
        } catch (InterruptedException e) {
            throw new InterruptedIOException();
        } finally {
            zkw.close();
        }
    }

    @Override
    public int getCurrentNrHRS() throws IOException {
        ZooKeeperKeepAliveConnection zkw = hci.getKeepAliveZooKeeperWatcher();
        try {
            // We go to zk rather than to master to get count of regions to avoid
            // HTable having a Master dependency.  See HBase-2828
            return ZKUtil.getNumberOfChildren(zkw, zkw.rsZNode);
        } catch (KeeperException ke) {
            throw new IOException("Unexpected ZooKeeper exception", ke);
        } finally {
            zkw.close();
        }
    }
}