org.springframework.data.cassandra

Interface ReactiveSession

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

DefaultBridgedReactiveSession

public interface ReactiveSession
extends Closeable

A session holds connections to a Cassandra cluster, allowing it to be queried. ReactiveSession executes queries and prepares statements in a reactive style returning results wrapped in Mono and Flux.

Each session maintains multiple connections to the cluster nodes, provides policies to choose which node to use for each query (round-robin on all nodes of the cluster by default), and handles retries for failed queries (when it makes sense).

Session instances are thread-safe and usually a single instance is enough per application. As a given session can only be "logged" into one keyspace at a time (where the "logged" keyspace is the one used by queries that don't explicitly use a fully qualified table name), it can make sense to create one session per keyspace used. This is however not necessary when querying multiple keyspaces since it is always possible to use a single session with fully qualified table names in queries.

Since:

2.0

Author:

Mark Paluch

See Also:

Publisher, Mono, ReactiveResultSet

Method Summary

Modifier and Type	Method and Description
void	close() Initiates a shutdown of this session instance and blocks until that shutdown completes.
reactor.core.publisher.Mono<ReactiveResultSet>	execute(com.datastax.oss.driver.api.core.cql.Statement<?> statement) Executes the provided query.
reactor.core.publisher.Mono<ReactiveResultSet>	execute(String query) Executes the provided query.
reactor.core.publisher.Mono<ReactiveResultSet>	execute(String query, Map<String,Object> values) Executes the provided query using the provided named values.
reactor.core.publisher.Mono<ReactiveResultSet>	execute(String query, Object... values) Executes the provided query using the provided values.
com.datastax.oss.driver.api.core.context.DriverContext	getContext() Returns a context that provides access to all the policies used by this driver instance.
boolean	isClosed() Whether this Session instance has been closed.
reactor.core.publisher.Mono<com.datastax.oss.driver.api.core.cql.PreparedStatement>	prepare(com.datastax.oss.driver.api.core.cql.SimpleStatement statement) Prepares the provided query.
reactor.core.publisher.Mono<com.datastax.oss.driver.api.core.cql.PreparedStatement>	prepare(String query) Prepares the provided query string.

Method Detail

isClosed

boolean isClosed()

Whether this Session instance has been closed.

Note that this method returns true as soon as the closing of this Session has started but it does not guarantee that the closing is done. If you want to guarantee that the closing is done, you can call close() and wait until it returns (or call the get method on closeAsync() with a very short timeout and check this doesn't timeout).

Returns:

true if this Session instance has been closed, false otherwise.

getContext

com.datastax.oss.driver.api.core.context.DriverContext getContext()

Returns a context that provides access to all the policies used by this driver instance.

Returns:

a context that provides access to all the policies used by this driver instance.

execute

reactor.core.publisher.Mono<ReactiveResultSet> execute(String query)

Executes the provided query.

This is a convenience method for execute(new SimpleStatement(query)).

Parameters:

query - the CQL query to execute.

Returns:

the result of the query. That result will never be null but can be empty (and will be for any non SELECT query).

execute

reactor.core.publisher.Mono<ReactiveResultSet> execute(String query,
                                                       Object... values)

Executes the provided query using the provided values.

This is a convenience method for execute(new SimpleStatement(query, values)).

Parameters:

query - the CQL query to execute.

values - values required for the execution of query. See SimpleStatement.newInstance(String, Object...) for more details.

Returns:

the result of the query. That result will never be null but can be empty (and will be for any non SELECT query).

execute

reactor.core.publisher.Mono<ReactiveResultSet> execute(String query,
                                                       Map<String,Object> values)

Executes the provided query using the provided named values.

This is a convenience method for execute(new SimpleStatement(query, values)).

Parameters:

query - the CQL query to execute.

values - values required for the execution of query. See SimpleStatement.newInstance(String, Map) for more details.

Returns:

the result of the query. That result will never be null but can be empty (and will be for any non SELECT query).

execute

reactor.core.publisher.Mono<ReactiveResultSet> execute(com.datastax.oss.driver.api.core.cql.Statement<?> statement)

Executes the provided query.

This method blocks until at least some result has been received from the database. However, for SELECT queries, it does not guarantee that the result has been received in full. But it does guarantee that some response has been received from the database, and in particular guarantees that if the request is invalid, an exception will be thrown by this method.

Parameters:

statement - the CQL query to execute (that can be any Statement).

Returns:

the result of the query. That result will never be null but can be empty (and will be for any non SELECT query).

prepare

reactor.core.publisher.Mono<com.datastax.oss.driver.api.core.cql.PreparedStatement> prepare(String query)

Prepares the provided query string.

Parameters:

query - the CQL query string to prepare

Returns:

the prepared statement corresponding to query.

prepare

reactor.core.publisher.Mono<com.datastax.oss.driver.api.core.cql.PreparedStatement> prepare(com.datastax.oss.driver.api.core.cql.SimpleStatement statement)

Prepares the provided query.

This method behaves like prepare(String), but note that the resulting PreparedStatement will inherit the query properties set on statement. Concretely, this means that in the following code:

 Statement toPrepare = SimpleStatement.newInstance("SELECT * FROM test WHERE k=?")
                .setConsistencyLevel(ConsistencyLevel.QUORUM);
 PreparedStatement prepared = session.prepare(toPrepare);
 session.execute(prepared.bind("someValue"));
 

the final execution will be performed with Quorum consistency.

Please note that if the same CQL statement is prepared more than once, all calls to this method will return the same PreparedStatement object but the method will still apply the properties of the prepared Statement to this object.

Parameters:

statement - the statement to prepare

Returns:

the prepared statement corresponding to statement.

Throws:

IllegalArgumentException - if statement.getValues() != null (values for executing a prepared statement should be provided after preparation though the PreparedStatement.bind(java.lang.Object...) method or through a corresponding BoundStatement).

close

void close()

Initiates a shutdown of this session instance and blocks until that shutdown completes.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable