Could not find implementation class: "cassandra"

I'm trying to connect to Titan backed with Cassandra (installed with the Rexster Titan-Server package) via Titan-Node.

I get the error...

java.lang.IllegalArgumentException: Could not find implementation class: "cassandra"

... when I run the following code....

var Titan = require('titan-node');
var gremlin = new Titan.Gremlin({ loglevel: 'OFF' });

var TitanFactory = gremlin.java.import('com.thinkaurelius.titan.core.TitanFactory');
var graph = TitanFactory.openSync('titan.config');

Config:

storage.directory = "/tmp/titan"
storage.backend = "cassandra"
storage.hostname = "127.0.0.1"
storage.port = 9160

Any ideas?

I seem to have the required .jar within my Titan installation folder and also in the target/dependency folder within the Titan-Node package.

Why can't Java find the file? Is there a missing classpath entry? If so would it need to be set for the database or for node? I figure it would be node because that's the app trying to load the class.

EDIT

Dan's suggestion gave me....

'java.lang.IllegalArgumentException: Could not find implementation class: "com.thinkaurelius.titan.diskstorage.cassandra.thrift.CassandraThriftStoreManager"'

...and...

'java.lang.IllegalArgumentException: Could not find implementation class: "com.thinkaurelius.titan.diskstorage.cassandra.astyanax.AstyanaxStoreManager"'

...respectively.

In fact whatever value you set storage.backend to in the config, that's the name of the class it can't find an implementation for that it reports in the exception message.

If you look in the code here...

https://github.com/thinkaurelius/titan/blob/master/titan-core/src/main/java/com/thinkaurelius/titan/diskstorage/Backend.java

...the instantiate method that is throwing the exception uses the method parameter clazzname in the message which is passed in by the call in getImplementationClass. The latter ought to be looking up the class to load via the key set in storage.backend but oddly it doesn't seem to find anything so it uses the value as is. Even so, it still can't find the class even if you set it directly. So there's a second mystery here.

I suppose I will have to go through Rexster until this is fixed.

At this time titan-node supports Titan 0.4.1 java jar files. You can upgrade it by replacing new Titan jar files. Then you can use the code bellow to connect to Titan

var Titan = require('titan-node');
var gremlin = new Titan.Gremlin({ loglevel: 'OFF' });

var BaseConfiguration = gremlin.java.import('org.apache.commons.configuration.BaseConfiguration');
var _confObj={'backend':'cassandra','hostname':'127.0.0.1'};
var TitanFactory = gremlin.java.import('com.thinkaurelius.titan.core.TitanFactory');

conf = new BaseConfiguration();
conf.setPropertySync("storage.backend",_confObj.backend);
conf.setPropertySync("storage.hostname",_confObj.hostname);
var graph = TitanFactory.openSync(conf);
var g = gremlin.wrap(graph);

g.addVertex(null, function (err, saturn) {
    console.log('added');
    g.commit(function() {
        console.log('commited');
    });
});