Unable to connect to cassandra using Hector - cassandra

Question

I am unable to access Casandra using Hector. Following is the code
import java.util.Arrays;
import java.util.List;
import me.prettyprint.cassandra.service.CassandraHostConfigurator;
import me.prettyprint.cassandra.service.ThriftCluster;
import me.prettyprint.cassandra.service.ThriftKsDef;
import me.prettyprint.hector.api.Cluster;
import me.prettyprint.hector.api.Keyspace;
import me.prettyprint.hector.api.ddl.ColumnFamilyDefinition;
import me.prettyprint.hector.api.ddl.KeyspaceDefinition;
import me.prettyprint.hector.api.factory.HFactory;
import me.prettyprint.hector.api.mutation.Mutator;
public class Hector {
public static void main (String[] args){
boolean cfExists = false;
Cluster cluster = HFactory.getOrCreateCluster("mycluster", new CassandraHostConfigurator("host:9160"));
Keyspace keyspace = HFactory.createKeyspace("Keyspace1", cluster);
// first check if the key space exists
KeyspaceDefinition keyspaceDetail = cluster.describeKeyspace("Keyspace1");
// if not, create one
if (keyspaceDetail == null) {
CassandraHostConfigurator cassandraHostConfigurator = new CassandraHostConfigurator("host:9160");
ThriftCluster cassandraCluster = new ThriftCluster("mycluster", cassandraHostConfigurator);
ColumnFamilyDefinition cfDef = HFactory.createColumnFamilyDefinition("Keyspace1", "base");
cassandraCluster.addKeyspace(new ThriftKsDef("Keyspace1", "org.apache.cassandra.locator.SimpleStrategy", 1,
Arrays.asList(cfDef)));
} else {
// even if the key space exists, we need to check if the column family exists
List<ColumnFamilyDefinition> columnFamilyDefinitions = keyspaceDetail.getCfDefs();
for (ColumnFamilyDefinition def : columnFamilyDefinitions) {
String columnFamilyName = def.getName();
if (columnFamilyName.equals("tcs_im"))
cfExists = true;
}
}
}
}
Encountering following error
log4j:WARN No appenders could be found for logger (me.prettyprint.cassandra.connection.CassandraHostRetryService).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.IllegalAccessError: tried to access class me.prettyprint.cassandra.service.JmxMonitor from class me.prettyprint.cassandra.connection.HConnectionManager
at me.prettyprint.cassandra.connection.HConnectionManager.(HConnectionManager.java:78)
at me.prettyprint.cassandra.service.AbstractCluster.(AbstractCluster.java:69)
at me.prettyprint.cassandra.service.AbstractCluster.(AbstractCluster.java:65)
at me.prettyprint.cassandra.service.ThriftCluster.(ThriftCluster.java:17)
at me.prettyprint.hector.api.factory.HFactory.createCluster(HFactory.java:176)
at me.prettyprint.hector.api.factory.HFactory.getOrCreateCluster(HFactory.java:155)
at com.im.tcs.Hector.main(Hector.java:20)
Please help as to why is it happening.

Answer 1

We use a CassandraConnection class as a convenience-class:
import me.prettyprint.cassandra.connection.DynamicLoadBalancingPolicy;
import me.prettyprint.cassandra.service.CassandraHostConfigurator;
import me.prettyprint.cassandra.service.ExhaustedPolicy;
import me.prettyprint.cassandra.service.OperationType;
import me.prettyprint.hector.api.Cluster;
import me.prettyprint.hector.api.HConsistencyLevel;
import me.prettyprint.hector.api.Keyspace;
import me.prettyprint.hector.api.factory.HFactory;
import java.util.HashMap;
import java.util.Map;
/**
* lazy connect
*/
final class CassandraConnection {
// Constants -----------------------------------------------------
private static final String HOSTS = "localhost";
private static final int PORT = "9160";
private static final String CLUSTER_NAME = "myCluster";
private static final int TIMEOUT = 500);
private static final String KEYSPACE = "Keyspace1";
private static final ConsistencyLevelPolicy CL_POLICY = new ConsistencyLevelPolicy();
// Attributes ----------------------------------------------------
private Cluster cluster;
private volatile Keyspace keyspace;
// Constructors --------------------------------------------------
CassandraConnection() {}
// Methods --------------------------------------------------------
Cluster getCluster() {
if (null == cluster) {
CassandraHostConfigurator config = new CassandraHostConfigurator();
config.setHosts(HOSTS);
config.setPort(PORT);
config.setUseThriftFramedTransport(true);
config.setUseSocketKeepalive(true);
config.setAutoDiscoverHosts(false);
// maxWorkerThreads provides the throttling for us. So hector can be let to grow freely...
config.setExhaustedPolicy(ExhaustedPolicy.WHEN_EXHAUSTED_GROW);
config.setMaxActive(1000); // hack since ExhaustedPolicy doesn't work
// suspend hosts if response is unacceptable for web response
config.setCassandraThriftSocketTimeout(TIMEOUT);
config.setUseHostTimeoutTracker(true);
config.setHostTimeoutCounter(3);
config.setLoadBalancingPolicy(new DynamicLoadBalancingPolicy());
cluster = HFactory.createCluster(CLUSTER_NAME, config);
}
return cluster;
}
Keyspace getKeyspace() {
if (null == keyspace) {
keyspace = HFactory.createKeyspace(KEYSPACE, getCluster(), CL_POLICY);
}
return keyspace;
}
private static class ConsistencyLevelPolicy implements me.prettyprint.hector.api.ConsistencyLevelPolicy {
#Override
public HConsistencyLevel get(final OperationType op) {
return HConsistencyLevel.ONE;
}
#Override
public HConsistencyLevel get(final OperationType op, final String cfName) {
return get(op);
}
}
}
Example of use:
private final CassandraConnection conn = new CassandraConnection();
SliceQuery<String, String, String> sliceQuery = HFactory.createSliceQuery(
conn.getKeyspace(), StringSerializer.get(), StringSerializer.get(), StringSerializer.get());
sliceQuery.setColumnFamily("myColumnFamily");
sliceQuery.setRange("", "", false, Integer.MAX_VALUE);
sliceQuery.setKey("myRowKey");
ColumnSlice<String, String> columnSlice = sliceQuery.execute().get();