org.neo4j.kernel.ha.zookeeper.ClusterManager.java Source code

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Here is the source code for org.neo4j.kernel.ha.zookeeper.ClusterManager.java

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/**
 * Copyright (c) 2002-2011 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.kernel.ha.zookeeper;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;

import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.ZooKeeper;

public class ClusterManager extends AbstractZooKeeperManager {
    private final ZooKeeper zooKeeper;
    private String rootPath;
    private KeeperState state = KeeperState.Disconnected;

    public ClusterManager(String zooKeeperServers) {
        super(zooKeeperServers, null);
        this.zooKeeper = instantiateZooKeeper();
    }

    @Override
    protected int getMyMachineId() {
        throw new UnsupportedOperationException("Not implemented ClusterManager.getMyMachineId()");
    }

    public void waitForSyncConnected() {
        long startTime = System.currentTimeMillis();
        while (System.currentTimeMillis() - startTime < SESSION_TIME_OUT) {
            if (state == KeeperState.SyncConnected) {
                // We are connected
                break;
            }
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                Thread.interrupted();
            }
        }
    }

    public void process(WatchedEvent event) {
        // System.out.println( "Got event: " + event );
        String path = event.getPath();
        if (path == null) {
            state = event.getState();
        }
    }

    public Machine getMaster() {
        return getMasterBasedOn(getAllMachines(true).values());
    }

    @Override
    public String getRoot() {
        if (rootPath == null) {
            rootPath = readRootPath();
        }
        return rootPath;
    }

    private String readRootPath() {
        waitForSyncConnected();
        String result = getSingleRootPath(getZooKeeper());
        if (result == null) {
            throw new RuntimeException("No root child found in zoo keeper");
        }
        return result;
    }

    public static String getSingleRootPath(ZooKeeper keeper) {
        try {
            List<String> children = keeper.getChildren("/", false);
            String foundChild = null;
            for (String child : children) {
                if (child.contains("_")) {
                    if (foundChild != null) {
                        throw new RuntimeException("Multiple roots found, " + foundChild + " and " + child);
                    }
                    foundChild = child;
                }
            }

            if (foundChild != null) {
                return "/" + foundChild;
            }
            return null;
        } catch (KeeperException e) {
            throw new RuntimeException(e);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Returns the disconnected slaves in this cluster so that all slaves
     * which are specified in the HA servers configuration, but not in the
     * zoo keeper cluster will be returned.
     * @return the disconnected slaves in this cluster.
     */
    //    public Machine[] getDisconnectedSlaves()
    //    {
    //        Collection<Machine> infos = new ArrayList<Machine>();
    //        for ( Map.Entry<Integer, String> entry : haServers.entrySet() )
    //        {
    //            infos.add( new Machine( entry.getKey(), -1, -1, entry.getValue() ) );
    //        }
    //        infos.removeAll( getAllMachines().values() );
    //        return infos.toArray( new Machine[infos.size()] );
    //    }

    /**
     * Returns the connected slaves in this cluster.
     * @return the connected slaves in this cluster.
     */
    public Machine[] getConnectedSlaves() {
        Map<Integer, Machine> machines = getAllMachines(true);
        Machine master = getMasterBasedOn(machines.values());
        Collection<Machine> result = new ArrayList<Machine>(machines.values());
        result.remove(master);
        return result.toArray(new Machine[result.size()]);
    }

    @Override
    protected ZooKeeper getZooKeeper() {
        return this.zooKeeper;
    }
}