Inserting data with Thrift and Cassandra 0.7

A lot has changed from Cassandra 0.6 to 0.7, and sometimes it is hard to find examples of how things work. I'll be posting how to's on some of the most usual operations you might want to perform when using Cassandra, written in Java.

First of you have to establish a connection to the server:

TFramedTransport transport = new TFramedTransport(new TSocket("localhost", 9160));
Cassandra.Client client = new Cassandra.Client(new TBinaryProtocol(transport));
transport.open();

Here I'm using localhost and the default port for Cassandra, but this can be configured.

One difference to the previous versions of Cassandra is that the connection can be bound to a keyspace, and can be set as so:

client.set_keyspace("Keyspace");

With the connection established you need only the data to insert, now. This data is passed to the server in the form of mutations (org.apache.cassandra.thrift.Mutation).

In this example, I'll be adding a column to a row in a column family in the predefined keyspace.


List<Mutation> insertion_list = new ArrayList<Mutation>();

Column col_to_add = new Column(ByteBuffer.wrap(("name").getBytes("UTF8")), ByteBuffer.wrap(("value").getBytes("UTF8")),System.currentTimeMillis());

Mutation mut = new Mutation();
mut.setColumn_or_supercolumn(new ColumnOrSuperColumn().setColumn(col_to_add));
insertion_list.add(mut);

Map<String,List<Mutation>> columnFamilyValues = new HashMap<String,List<Mutation>>();
columnFamilyValues.put("columnFamily",insertion_list);

Map<ByteBuffer,<String,List<Mutation>>> rowDefinition = new HashMap<ByteBuffer,<String,List<Mutation>>>();
rowDefinition.put(ByteBuffer.wrap(("key").getBytes("UTF8")),columnFamilyValues);

client.batch_mutate(rowDefinition,ConsistencyLevel.ONE);


The code is pretty much self explaining, apart from some values that can be reconfigured at will, as the encoding of the strings (I've used UTF8), and the consistency level of the insertion (I've used ONE).

In the case of the consistency levels you should check out Cassandra's wiki, to better understand it's usage.

To close the connection to the server it as easy as,

transport.close();

Hope you find this useful. Next I'll give an example of how to get data from the server, as soon as I have some time. ;)