ZkState.java

package storm.kafka;

import backtype.storm.Config;
import backtype.storm.utils.Utils;
import com.netflix.curator.framework.CuratorFramework;
import com.netflix.curator.framework.CuratorFrameworkFactory;
import com.netflix.curator.retry.RetryNTimes;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.zookeeper.CreateMode;
import org.json.simple.JSONValue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZkState {
    public static final Logger LOG = LoggerFactory.getLogger(ZkState.class);
    CuratorFramework _curator;

    private CuratorFramework newCurator(Map stateConf) throws Exception {
        Integer port = (Integer)stateConf.get(Config.TRANSACTIONAL_ZOOKEEPER_PORT);
	String serverPorts = "";
        for(String server: (List<String>)stateConf.get(Config.TRANSACTIONAL_ZOOKEEPER_SERVERS)) {
            serverPorts = serverPorts + server + ":" + port + ",";
        }
	return CuratorFrameworkFactory.newClient(serverPorts,
		Utils.getInt(stateConf.get(Config.STORM_ZOOKEEPER_SESSION_TIMEOUT)), 
		15000, 
		new RetryNTimes(Utils.getInt(stateConf.get(Config.STORM_ZOOKEEPER_RETRY_TIMES)),
				Utils.getInt(stateConf.get(Config.STORM_ZOOKEEPER_RETRY_INTERVAL))));
    }

    public CuratorFramework getCurator() {
	assert _curator != null;
        return _curator;
    }

    public ZkState(Map stateConf) {
	stateConf = new HashMap(stateConf);

	try {
	    _curator = newCurator(stateConf);
	    _curator.start();
	} catch(Exception e) {
	    throw new RuntimeException(e);
	}
    }

    public void writeJSON(String path, Map<Object,Object> data) {
	LOG.info("Writing " + path + " the data " + data.toString());
        writeBytes(path, JSONValue.toJSONString(data).getBytes(Charset.forName("UTF-8")));
    }

    public void writeBytes(String path, byte[] bytes) {
        try {
            if(_curator.checkExists().forPath(path)==null) {
                _curator.create()
                        .creatingParentsIfNeeded()
                        .withMode(CreateMode.PERSISTENT)
                        .forPath(path, bytes);
            } else {
		_curator.setData().forPath(path, bytes);
	    }
        } catch(Exception e) {
            throw new RuntimeException(e);
        }
    }

    public Map<Object,Object> readJSON(String path) {
	try {
	    byte[] b = readBytes(path);
	    if(b==null) return null;
	    return (Map<Object,Object>)JSONValue.parse(new String(b, "UTF-8"));
	} catch(Exception e) {
	    throw new RuntimeException(e);
	}
    }

    public byte[] readBytes(String path) {
        try {
            if(_curator.checkExists().forPath(path)!=null) {
		return _curator.getData().forPath(path);
            } else {
                return null;
            }
        } catch(Exception e) {
            throw new RuntimeException(e);
        }
    }

    public void close() {
	_curator.close();
	_curator = null;
    }
}