com.aquenos.cassandra.pvarchiver.server.database

Interface CassandraProvider

All Known Implementing Classes:

CassandraProviderBean, ThrottlingCassandraProvider

public interface CassandraProvider

Provides access to a Cassandra cluster through the Cluster and Session objects.

Once initialized, the provider publishes a CassandraProviderInitializedEvent in the application context, which can be used by other beans that need access to the Cassandra cluster in order to get a reference to the provider when it is ready to be used.

Alternatively, the futures provided by the getClusterFuture() and getSessionFuture() methods can be used. These futures complete once the respective object becomes available.

Author:

Sebastian Marsching

Method Summary

Modifier and Type	Method and Description
Cluster	getCluster() Returns a reference to the Cassandra cluster.
ListenableFuture<Cluster>	getClusterFuture() Returns a future reference to the Cassandra cluster.
Session	getSession() Returns a reference to the Cassandra session.
ListenableFuture<Session>	getSessionFuture() Returns a future reference to the Cassandra session.
boolean	isInitialized() Tells whether this provider has been completely initialized.

Method Detail

getCluster

Cluster getCluster()

Returns a reference to the Cassandra cluster.

Returns:

reference to the Cassandra cluster.

Throws:

AuthenticationException - if the connection to the cluster could not be established (yet) because there is an authentication problem.

IllegalStateException - if the provider has not been fully initialized yet or has already been destroyed.

NoHostAvailableException - if the connection to the cluster could not be established (yet) because none of the configured hosts is available at the moment.

See Also:

getClusterFuture()

getClusterFuture

ListenableFuture<Cluster> getClusterFuture()

Returns a future reference to the Cassandra cluster. The returned future completes when the cluster instance become available. The future might not complete for a very long time if a connection to the cluster cannot be established. The returned future will only throw an exception if the Cassandra provider is destroyed before the cluster instance becomes available. In all other cases, the Cassandra provider will wait for a later attempt to create a cluster instance to succeed.

Returns:

future that provides access to the Cassandra cluster instance once it becomes available. The cluster will be the same one as the one returned by getCluster().

See Also:

getCluster()

isInitialized

boolean isInitialized()

Tells whether this provider has been completely initialized. If true, getCluster() and getSession() will return a result and not throw an exception.

Please note that the provider might be destroyed after calling this method. In this case, getCluster() and getSession() might throw, even if this method returned true previously.

Returns:

true if this provider is ready for operation, false otherwise.

getSession

Session getSession()

Returns a reference to the Cassandra session. The session can be used to run queries on the Cassandra cluster. The provider might bind the session to the correct keyspace so that other components can automatically operate on the keyspace without having to know the keyspace name.

Returns:

reference to the Cassandra session.

Throws:

AuthenticationException - if the connection to the cluster could not be established (yet) because there is an authentication problem.

IllegalStateException - if the provider has not been fully initialized yet or has already been destroyed.

InvalidQueryException - if the provider tried to bind the session to a keyspace, but the keyspace did not exist (yet).

NoHostAvailableException - if the connection to the cluster could not be established (yet) because none of the configured hosts is available at the moment.

See Also:

getSessionFuture()

getSessionFuture

ListenableFuture<Session> getSessionFuture()

Returns a future reference to the Cassandra session. The returned future completes when the session instance become available. The future might not complete for a very long time if a connection to the cluster cannot be established or the keyspace cannot be accessed. The returned future will only throw an exception if the Cassandra provider is destroyed before the session instance becomes available. In all other cases, the Cassandra provider will wait for a later attempt to create a session instance to succeed.

Returns:

future that provides access to the Cassandra session instance once it becomes available. The session will be the same one as the one returned by getSession().

See Also:

getSession()